Skip to content

Conversation

@njpillitteri
Copy link
Contributor

When you try to remove the admc_adc module from the kernel, it segfaults.

The reason is that the probe function calls "axiadc_configure_ring_stream" and the remove function currently calls "axiadc_unconfigure_ring". The bug is fixed by modifying the remove function to call "axiadc_unconfigure_ring_stream" instead.

mhennerich added a commit that referenced this pull request May 18, 2015
iio: admc_adc: use axiadc_unconfigure_ring_stream() in remove function
@mhennerich mhennerich merged commit ec80f57 into analogdevicesinc:xcomm_zynq May 18, 2015
andreamerello pushed a commit to andreamerello/linux-analogdevices that referenced this pull request Nov 19, 2015
commit 3f1f9b8 upstream.

This fixes the following lockdep complaint:

[ INFO: possible circular locking dependency detected ]
3.16.0-rc2-mm1+ analogdevicesinc#7 Tainted: G           O
-------------------------------------------------------
kworker/u24:0/4356 is trying to acquire lock:
 (&(&sbi->s_es_lru_lock)->rlock){+.+.-.}, at: [<ffffffff81285fff>] __ext4_es_shrink+0x4f/0x2e0

but task is already holding lock:
 (&ei->i_es_lock){++++-.}, at: [<ffffffff81286961>] ext4_es_insert_extent+0x71/0x180

which lock already depends on the new lock.

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ei->i_es_lock);
                               lock(&(&sbi->s_es_lru_lock)->rlock);
                               lock(&ei->i_es_lock);
  lock(&(&sbi->s_es_lru_lock)->rlock);

 *** DEADLOCK ***

6 locks held by kworker/u24:0/4356:
 #0:  ("writeback"){.+.+.+}, at: [<ffffffff81071d00>] process_one_work+0x180/0x560
 analogdevicesinc#1:  ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff81071d00>] process_one_work+0x180/0x560
 analogdevicesinc#2:  (&type->s_umount_key#22){++++++}, at: [<ffffffff811a9c74>] grab_super_passive+0x44/0x90
 analogdevicesinc#3:  (jbd2_handle){+.+...}, at: [<ffffffff812979f9>] start_this_handle+0x189/0x5f0
 analogdevicesinc#4:  (&ei->i_data_sem){++++..}, at: [<ffffffff81247062>] ext4_map_blocks+0x132/0x550
 analogdevicesinc#5:  (&ei->i_es_lock){++++-.}, at: [<ffffffff81286961>] ext4_es_insert_extent+0x71/0x180

stack backtrace:
CPU: 0 PID: 4356 Comm: kworker/u24:0 Tainted: G           O   3.16.0-rc2-mm1+ analogdevicesinc#7
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Workqueue: writeback bdi_writeback_workfn (flush-253:0)
 ffffffff8213dce0 ffff880014b07538 ffffffff815df0bb 0000000000000007
 ffffffff8213e040 ffff880014b07588 ffffffff815db3dd ffff880014b07568
 ffff880014b07610 ffff88003b868930 ffff88003b868908 ffff88003b868930
Call Trace:
 [<ffffffff815df0bb>] dump_stack+0x4e/0x68
 [<ffffffff815db3dd>] print_circular_bug+0x1fb/0x20c
 [<ffffffff810a7a3e>] __lock_acquire+0x163e/0x1d00
 [<ffffffff815e89dc>] ? retint_restore_args+0xe/0xe
 [<ffffffff815ddc7b>] ? __slab_alloc+0x4a8/0x4ce
 [<ffffffff81285fff>] ? __ext4_es_shrink+0x4f/0x2e0
 [<ffffffff810a8707>] lock_acquire+0x87/0x120
 [<ffffffff81285fff>] ? __ext4_es_shrink+0x4f/0x2e0
 [<ffffffff8128592d>] ? ext4_es_free_extent+0x5d/0x70
 [<ffffffff815e6f09>] _raw_spin_lock+0x39/0x50
 [<ffffffff81285fff>] ? __ext4_es_shrink+0x4f/0x2e0
 [<ffffffff8119760b>] ? kmem_cache_alloc+0x18b/0x1a0
 [<ffffffff81285fff>] __ext4_es_shrink+0x4f/0x2e0
 [<ffffffff812869b8>] ext4_es_insert_extent+0xc8/0x180
 [<ffffffff812470f4>] ext4_map_blocks+0x1c4/0x550
 [<ffffffff8124c4c4>] ext4_writepages+0x6d4/0xd00
	...

Reported-by: Minchan Kim <[email protected]>
Signed-off-by: Theodore Ts'o <[email protected]>
Reported-by: Minchan Kim <[email protected]>
Cc: Zheng Liu <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
lclausen-adi pushed a commit that referenced this pull request Feb 15, 2016
When a43eec3 ("bpf: introduce bpf_perf_event_output() helper") added
PERF_COUNT_SW_BPF_OUTPUT we ended up with a new entry in the event_symbols_sw
array that wasn't initialized, thus set to NULL, fix print_symbol_events()
to check for that case so that we don't crash if this happens again.

  (gdb) bt
  #0  __match_glob (ignore_space=false, pat=<optimized out>, str=<optimized out>) at util/string.c:198
  #1  strglobmatch (str=<optimized out>, pat=pat@entry=0x7fffffffe61d "stall") at util/string.c:252
  #2  0x00000000004993a5 in print_symbol_events (type=1, syms=0x872880 <event_symbols_sw+160>, max=11, name_only=false, event_glob=0x7fffffffe61d "stall")
      at util/parse-events.c:1615
  #3  print_events (event_glob=event_glob@entry=0x7fffffffe61d "stall", name_only=false) at util/parse-events.c:1675
  #4  0x000000000042c79e in cmd_list (argc=1, argv=0x7fffffffe390, prefix=<optimized out>) at builtin-list.c:68
  #5  0x00000000004788a5 in run_builtin (p=p@entry=0x871758 <commands+120>, argc=argc@entry=2, argv=argv@entry=0x7fffffffe390) at perf.c:370
  #6  0x0000000000420ab0 in handle_internal_command (argv=0x7fffffffe390, argc=2) at perf.c:429
  #7  run_argv (argv=0x7fffffffe110, argcp=0x7fffffffe11c) at perf.c:473
  #8  main (argc=2, argv=0x7fffffffe390) at perf.c:588
  (gdb) p event_symbols_sw[PERF_COUNT_SW_BPF_OUTPUT]
  $4 = {symbol = 0x0, alias = 0x0}
  (gdb)

A patch to robustify perf to not segfault when the next counter gets added in
the kernel will follow this one.

Reported-by: Ingo Molnar <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
mhennerich pushed a commit that referenced this pull request Apr 5, 2016
Fixes segmentation fault using, for instance:

  (gdb) run record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls
  Starting program: /home/acme/bin/perf record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls
  Missing separate debuginfos, use: dnf debuginfo-install glibc-2.22-7.fc23.x86_64
  [Thread debugging using libthread_db enabled]
  Using host libthread_db library "/lib64/libthread_db.so.1".

 Program received signal SIGSEGV, Segmentation fault.
  0 x00000000004b9ea5 in tracepoint_error (e=0x0, err=13, sys=0x19b1370 "sched", name=0x19a5d00 "sched_switch") at util/parse-events.c:410
  (gdb) bt
  #0  0x00000000004b9ea5 in tracepoint_error (e=0x0, err=13, sys=0x19b1370 "sched", name=0x19a5d00 "sched_switch") at util/parse-events.c:410
  #1  0x00000000004b9fc5 in add_tracepoint (list=0x19a5d20, idx=0x7fffffffb8c0, sys_name=0x19b1370 "sched", evt_name=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:433
  #2  0x00000000004ba334 in add_tracepoint_event (list=0x19a5d20, idx=0x7fffffffb8c0, sys_name=0x19b1370 "sched", evt_name=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:498
  #3  0x00000000004bb699 in parse_events_add_tracepoint (list=0x19a5d20, idx=0x7fffffffb8c0, sys=0x19b1370 "sched", event=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:936
  #4  0x00000000004f6eda in parse_events_parse (_data=0x7fffffffb8b0, scanner=0x19a49d0) at util/parse-events.y:391
  #5  0x00000000004bc8e5 in parse_events__scanner (str=0x663ff2 "sched:sched_switch", data=0x7fffffffb8b0, start_token=258) at util/parse-events.c:1361
  #6  0x00000000004bca57 in parse_events (evlist=0x19a5220, str=0x663ff2 "sched:sched_switch", err=0x0) at util/parse-events.c:1401
  #7  0x0000000000518d5f in perf_evlist__can_select_event (evlist=0x19a3b90, str=0x663ff2 "sched:sched_switch") at util/record.c:253
  #8  0x0000000000553c42 in intel_pt_track_switches (evlist=0x19a3b90) at arch/x86/util/intel-pt.c:364
  #9  0x00000000005549d1 in intel_pt_recording_options (itr=0x19a2c40, evlist=0x19a3b90, opts=0x8edf68 <record+232>) at arch/x86/util/intel-pt.c:664
  #10 0x000000000051e076 in auxtrace_record__options (itr=0x19a2c40, evlist=0x19a3b90, opts=0x8edf68 <record+232>) at util/auxtrace.c:539
  #11 0x0000000000433368 in cmd_record (argc=1, argv=0x7fffffffde60, prefix=0x0) at builtin-record.c:1264
  #12 0x000000000049bec2 in run_builtin (p=0x8fa2a8 <commands+168>, argc=5, argv=0x7fffffffde60) at perf.c:390
  #13 0x000000000049c12a in handle_internal_command (argc=5, argv=0x7fffffffde60) at perf.c:451
  #14 0x000000000049c278 in run_argv (argcp=0x7fffffffdcbc, argv=0x7fffffffdcb0) at perf.c:495
  #15 0x000000000049c60a in main (argc=5, argv=0x7fffffffde60) at perf.c:618
(gdb)

Intel PT attempts to find the sched:sched_switch tracepoint but that seg
faults if tracefs is not readable, because the error reporting structure
is null, as errors are not reported when automatically adding
tracepoints.  Fix by checking before using.

Committer note:

This doesn't take place in a kernel that supports
perf_event_attr.context_switch, that is the default way that will be
used for tracking context switches, only in older kernels, like 4.2, in
a machine with Intel PT (e.g. Broadwell) for non-priviledged users.

Further info from a similar patch by Wang:

The error is in tracepoint_error: it assumes the 'e' parameter is valid.

However, there are many situation a parse_event() can be called without
parse_events_error. See result of

  $ grep 'parse_events(.*NULL)' ./tools/perf/ -r'

Signed-off-by: Adrian Hunter <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Tong Zhang <[email protected]>
Cc: Wang Nan <[email protected]>
Cc: [email protected] # v4.4+
Fixes: 1965817 ("perf tools: Enhance parsing events tracepoint error output")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
lclausen-adi pushed a commit that referenced this pull request Jul 11, 2016
The incorrect GPIO mask cause kernel warning, when AR9462 access GPIO11.
Also fix the mask for AR9565.

WARNING: CPU: 1 PID: 199 at ../drivers/net/wireless/ath/ath9k/hw.c:2778 ath9k_hw_gpio_get+0x1a9/0x1b0 [ath9k_hw]
CPU: 1 PID: 199 Comm: kworker/u16:9 Not tainted 4.7.0-rc1-next-20160530+ #5
Hardware name: Acer TravelMate P243/BA40_HC, BIOS V1.01 04/20/2012
Workqueue: events_power_efficient rfkill_poll
 0000000000000000 ffff88002cf73d28 ffffffff813b8ddc 0000000000000000
 0000000000000000 ffff88002cf73d68 ffffffff8107a331 00000ada00000086
 ffff880148d9c018 000000000000000b ffff880147e68720 0000000000000200
Call Trace:
 [<ffffffff813b8ddc>] dump_stack+0x63/0x87
 [<ffffffff8107a331>] __warn+0xd1/0xf0
 [<ffffffff8107a41d>] warn_slowpath_null+0x1d/0x20
 [<ffffffffc0775b19>] ath9k_hw_gpio_get+0x1a9/0x1b0 [ath9k_hw]
 [<ffffffffc047f3e4>] ath9k_rfkill_poll_state+0x34/0x60 [ath9k]
 [<ffffffffc06dbb53>] ieee80211_rfkill_poll+0x33/0x40 [mac80211]
 [<ffffffffc03ad65a>] cfg80211_rfkill_poll+0x2a/0xc0 [cfg80211]
 [<ffffffff817c5514>] rfkill_poll+0x24/0x50
 [<ffffffff81093183>] process_one_work+0x153/0x3f0
 [<ffffffff8109393b>] worker_thread+0x12b/0x4b0
 [<ffffffff81093810>] ? rescuer_thread+0x340/0x340
 [<ffffffff81099129>] kthread+0xc9/0xe0
 [<ffffffff817d8f1f>] ret_from_fork+0x1f/0x40
 [<ffffffff81099060>] ? kthread_park+0x60/0x60

Fixes: a01ab81 ("ath9k: define correct GPIO numbers and bits mask")
Reported-by: Sudip Mukherjee <[email protected]>
Tested-by: Sudip Mukherjee <[email protected]>
Signed-off-by: Miaoqing Pan <[email protected]>
Signed-off-by: Kalle Valo <[email protected]>
lclausen-adi pushed a commit that referenced this pull request Aug 2, 2016
This commit bd0b9ac ("genirq: Remove irq argument from irq flow handlers")
Modified the number of arguments of the irq flow handlers.

With the current driver we are seeing a kernel crash
because of the above commit.

Crash log:
Unable to handle kernel NULL pointer dereference at virtual address 0000002
pgd = c0004000
[0000002] *pgd=00000000
Internal error: Oops - BUG: 17 [#1] PREEMPT SMP ARM
Modules linked in: axi_timer
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-xilinx #5
Hardware name: Xilinx Zynq Platform
task: c0923870 ti: c091e000 task.ti: c091e000
PC is at intc_handler+0x18/0x8c
LR is at 0x1
pc : [<c01e91cc>]    lr : [<00000001>]    psr: 6001019
sp : c091fee0  ip : 00000002  fp : 00000001
r10: 00000000  r9 : 00000008  r8 : 00000001
r7 : ef002600  r6 : c091a464  r5 : 00000010  r4 : 00000000
r3 : 00000000  r2 : 00000000  r1 : ef003c40  r0 : 00000000
Flags: nZCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 18c5387d  Table: 2f16c04a  DAC: 00000051
Process swapper/0 (pid: 0, stack limit = 0xc091e210)
Stack: (0xc091fee0 to 0xc0920000)
fee0: 00000000 00000000 c091a464 ef002600 00000001 c00576ec 00000000 c00579a8
ff00: f8f00100 c0920f7c c091ff30 c092ec00 f8f01100 c00093ac c0383918 60010013
ff20: ffffffff c091ff64 638ff226 c0013014 00000000 00000008 c091d000 ef7d7000
ff40: ef7d6618 00000001 7725eac9 00000008 638ff226 00000008 00000000 00000001
ff60: 00000008 c091ff80 c03838f4 c0383918 60010013 ffffffff 00000051 c03838e8
ff80: 3b993807 00000000 7725eac9 00000008 c091e000 ef7d6618 c091e000 c094d0e0
ffa0: c0919364 c091ffb8 c06aba30 00000000 00000000 c0050538 c0920400 c067ebdc
ffc0: ffffffff ffffffff 00000000 c067e66c 00000000 c06aba30 00000000 c0954b94
ffe0: c0920480 c06aba2c c0924984 0000406a 413fc090 0000807c 00000000 00000000
[<c01e91cc>] (intc_handler) from [<c00576ec>] (generic_handle_irq+0x18/0x28)
[<c00576ec>] (generic_handle_irq) from [<c00579a8>] (__handle_domain_irq+0x88/0xb0)
[<c00579a8>] (__handle_domain_irq) from [<c00093ac>] (gic_handle_irq+0x50/0x90)
[<c00093ac>] (gic_handle_irq) from [<c0013014>] (__irq_svc+0x54/0x90)
Exception stack(0xc091ff30 to 0xc091ff78)
ff20:                                     00000000 00000008 c091d000 ef7d7000
ff40: ef7d6618 00000001 7725eac9 00000008 638ff226 00000008 00000000 00000001
ff60: 00000008 c091ff80 c03838f4 c0383918 60010013 ffffffff
[<c0013014>] (__irq_svc) from [<c0383918>] (cpuidle_enter_state+0xe8/0x1bc)
[<c0383918>] (cpuidle_enter_state) from [<c0050538>] (cpu_startup_entry+0x19c/0x1ec)
[<c0050538>] (cpu_startup_entry) from [<c067ebdc>] (start_kernel+0x328/0x388)
Code: ebf9c52b e3500000 15904010 01a04000 (e595301c)
---[ end trace 1b82d42394b8ee22 ]---
Kernel panic - not syncing: Fatal exception in interrupt
CPU1: stopping
CPU: 1 PID: 0 Comm: swapper/1 Tainted: G      D         4.4.0-xilinx #5
Hardware name: Xilinx Zynq Platform
[<c00163b8>] (unwind_backtrace) from [<c0012620>] (show_stack+0x10/0x14)
[<c0012620>] (show_stack) from [<c01c824c>] (dump_stack+0x80/0xcc)
[<c01c824c>] (dump_stack) from [<c0014c2c>] (ipi_cpu_stop+0x3c/0x6c)
[<c0014c2c>] (ipi_cpu_stop) from [<c0015344>] (handle_IPI+0x64/0x84)
[<c0015344>] (handle_IPI) from [<c00093d0>] (gic_handle_irq+0x74/0x90)
[<c00093d0>] (gic_handle_irq) from [<c0013014>] (__irq_svc+0x54/0x90)
Exception stack(0xef06bf68 to 0xef06bfb0)
bf60:                   00000000 00000008 c091d000 ef7e3000 ef7e2618 00000001
bf80: 845530d3 00000008 668ca7c3 00000008 00000000 00000001 00000008 ef06bfb8
bfa0: c03838f4 c0383918 600d0013 ffffffff
[<c0013014>] (__irq_svc) from [<c0383918>] (cpuidle_enter_state+0xe8/0x1bc)
[<c0383918>] (cpuidle_enter_state) from [<c0050538>] (cpu_startup_entry+0x19c/0x1ec)
[<c0050538>] (cpu_startup_entry) from [<0000948c>] (0x948c)
---[ end Kernel panic - not syncing: Fatal exception in interrupt

This patch fixes this issue in the driver
--> By updating the number of arguments in the flow handler to one.
--> Use irq_desc_get_chip instead of irq_get_chip

Signed-off-by: Kedareswara rao Appana <[email protected]>
Signed-off-by: Michal Simek <[email protected]>
commodo pushed a commit that referenced this pull request Apr 26, 2018
[ Upstream commit d754941 ]

If, for any reason, userland shuts down iscsi transport interfaces
before proper logouts - like when logging in to LUNs manually, without
logging out on server shutdown, or when automated scripts can't
umount/logout from logged LUNs - kernel will hang forever on its
sd_sync_cache() logic, after issuing the SYNCHRONIZE_CACHE cmd to all
still existent paths.

PID: 1 TASK: ffff8801a69b8000 CPU: 1 COMMAND: "systemd-shutdow"
 #0 [ffff8801a69c3a30] __schedule at ffffffff8183e9ee
 #1 [ffff8801a69c3a80] schedule at ffffffff8183f0d5
 #2 [ffff8801a69c3a98] schedule_timeout at ffffffff81842199
 #3 [ffff8801a69c3b40] io_schedule_timeout at ffffffff8183e604
 #4 [ffff8801a69c3b70] wait_for_completion_io_timeout at ffffffff8183fc6c
 #5 [ffff8801a69c3bd0] blk_execute_rq at ffffffff813cfe10
 #6 [ffff8801a69c3c88] scsi_execute at ffffffff815c3fc7
 #7 [ffff8801a69c3cc8] scsi_execute_req_flags at ffffffff815c60fe
 #8 [ffff8801a69c3d30] sd_sync_cache at ffffffff815d37d7
 #9 [ffff8801a69c3da8] sd_shutdown at ffffffff815d3c3c

This happens because iscsi_eh_cmd_timed_out(), the transport layer
timeout helper, would tell the queue timeout function (scsi_times_out)
to reset the request timer over and over, until the session state is
back to logged in state. Unfortunately, during server shutdown, this
might never happen again.

Other option would be "not to handle" the issue in the transport
layer. That would trigger the error handler logic, which would also need
the session state to be logged in again.

Best option, for such case, is to tell upper layers that the command was
handled during the transport layer error handler helper, marking it as
DID_NO_CONNECT, which will allow completion and inform about the
problem.

After the session was marked as ISCSI_STATE_FAILED, due to the first
timeout during the server shutdown phase, all subsequent cmds will fail
to be queued, allowing upper logic to fail faster.

Signed-off-by: Rafael David Tinoco <[email protected]>
Reviewed-by: Lee Duncan <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
commodo pushed a commit that referenced this pull request Apr 26, 2018
[ Upstream commit 2c0aa08 ]

Scenario:
1. Port down and do fail over
2. Ap do rds_bind syscall

PID: 47039  TASK: ffff89887e2fe640  CPU: 47  COMMAND: "kworker/u:6"
 #0 [ffff898e35f159f0] machine_kexec at ffffffff8103abf9
 #1 [ffff898e35f15a60] crash_kexec at ffffffff810b96e3
 #2 [ffff898e35f15b30] oops_end at ffffffff8150f518
 #3 [ffff898e35f15b60] no_context at ffffffff8104854c
 #4 [ffff898e35f15ba0] __bad_area_nosemaphore at ffffffff81048675
 #5 [ffff898e35f15bf0] bad_area_nosemaphore at ffffffff810487d3
 #6 [ffff898e35f15c00] do_page_fault at ffffffff815120b8
 #7 [ffff898e35f15d10] page_fault at ffffffff8150ea95
    [exception RIP: unknown or invalid address]
    RIP: 0000000000000000  RSP: ffff898e35f15dc8  RFLAGS: 00010282
    RAX: 00000000fffffffe  RBX: ffff889b77f6fc00  RCX:ffffffff81c99d88
    RDX: 0000000000000000  RSI: ffff896019ee08e8  RDI:ffff889b77f6fc00
    RBP: ffff898e35f15df0   R8: ffff896019ee08c8  R9:0000000000000000
    R10: 0000000000000400  R11: 0000000000000000  R12:ffff896019ee08c0
    R13: ffff889b77f6fe68  R14: ffffffff81c99d80  R15: ffffffffa022a1e0
    ORIG_RAX: ffffffffffffffff  CS: 0010 SS: 0018
 #8 [ffff898e35f15dc8] cma_ndev_work_handler at ffffffffa022a228 [rdma_cm]
 #9 [ffff898e35f15df8] process_one_work at ffffffff8108a7c6
 #10 [ffff898e35f15e58] worker_thread at ffffffff8108bda0
 #11 [ffff898e35f15ee8] kthread at ffffffff81090fe6

PID: 45659  TASK: ffff880d313d2500  CPU: 31  COMMAND: "oracle_45659_ap"
 #0 [ffff881024ccfc98] __schedule at ffffffff8150bac4
 #1 [ffff881024ccfd40] schedule at ffffffff8150c2cf
 #2 [ffff881024ccfd50] __mutex_lock_slowpath at ffffffff8150cee7
 #3 [ffff881024ccfdc0] mutex_lock at ffffffff8150cdeb
 #4 [ffff881024ccfde0] rdma_destroy_id at ffffffffa022a027 [rdma_cm]
 #5 [ffff881024ccfe10] rds_ib_laddr_check at ffffffffa0357857 [rds_rdma]
 #6 [ffff881024ccfe50] rds_trans_get_preferred at ffffffffa0324c2a [rds]
 #7 [ffff881024ccfe80] rds_bind at ffffffffa031d690 [rds]
 #8 [ffff881024ccfeb0] sys_bind at ffffffff8142a670

PID: 45659                          PID: 47039
rds_ib_laddr_check
  /* create id_priv with a null event_handler */
  rdma_create_id
  rdma_bind_addr
    cma_acquire_dev
      /* add id_priv to cma_dev->id_list */
      cma_attach_to_dev
                                    cma_ndev_work_handler
                                      /* event_hanlder is null */
                                      id_priv->id.event_handler

Signed-off-by: Guanglei Li <[email protected]>
Signed-off-by: Honglei Wang <[email protected]>
Reviewed-by: Junxiao Bi <[email protected]>
Reviewed-by: Yanjun Zhu <[email protected]>
Reviewed-by: Leon Romanovsky <[email protected]>
Acked-by: Santosh Shilimkar <[email protected]>
Acked-by: Doug Ledford <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
commodo pushed a commit that referenced this pull request Jul 16, 2018
Three attributes are currently not verified, thus can trigger KMSAN
warnings such as :

BUG: KMSAN: uninit-value in __arch_swab32 arch/x86/include/uapi/asm/swab.h:10 [inline]
BUG: KMSAN: uninit-value in __fswab32 include/uapi/linux/swab.h:59 [inline]
BUG: KMSAN: uninit-value in nfqnl_recv_config+0x939/0x17d0 net/netfilter/nfnetlink_queue.c:1268
CPU: 1 PID: 4521 Comm: syz-executor120 Not tainted 4.17.0+ #5
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x188/0x2a0 mm/kmsan/kmsan.c:1117
 __msan_warning_32+0x70/0xc0 mm/kmsan/kmsan_instr.c:620
 __arch_swab32 arch/x86/include/uapi/asm/swab.h:10 [inline]
 __fswab32 include/uapi/linux/swab.h:59 [inline]
 nfqnl_recv_config+0x939/0x17d0 net/netfilter/nfnetlink_queue.c:1268
 nfnetlink_rcv_msg+0xb2e/0xc80 net/netfilter/nfnetlink.c:212
 netlink_rcv_skb+0x37e/0x600 net/netlink/af_netlink.c:2448
 nfnetlink_rcv+0x2fe/0x680 net/netfilter/nfnetlink.c:513
 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
 netlink_unicast+0x1680/0x1750 net/netlink/af_netlink.c:1336
 netlink_sendmsg+0x104f/0x1350 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg net/socket.c:639 [inline]
 ___sys_sendmsg+0xec8/0x1320 net/socket.c:2117
 __sys_sendmsg net/socket.c:2155 [inline]
 __do_sys_sendmsg net/socket.c:2164 [inline]
 __se_sys_sendmsg net/socket.c:2162 [inline]
 __x64_sys_sendmsg+0x331/0x460 net/socket.c:2162
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x43fd59
RSP: 002b:00007ffde0e30d28 EFLAGS: 00000213 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fd59
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000004002c8 R11: 0000000000000213 R12: 0000000000401680
R13: 0000000000401710 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:279 [inline]
 kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:189
 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:315
 kmsan_slab_alloc+0x10/0x20 mm/kmsan/kmsan.c:322
 slab_post_alloc_hook mm/slab.h:446 [inline]
 slab_alloc_node mm/slub.c:2753 [inline]
 __kmalloc_node_track_caller+0xb35/0x11b0 mm/slub.c:4395
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x2cb/0x9e0 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:988 [inline]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1182 [inline]
 netlink_sendmsg+0x76e/0x1350 net/netlink/af_netlink.c:1876
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg net/socket.c:639 [inline]
 ___sys_sendmsg+0xec8/0x1320 net/socket.c:2117
 __sys_sendmsg net/socket.c:2155 [inline]
 __do_sys_sendmsg net/socket.c:2164 [inline]
 __se_sys_sendmsg net/socket.c:2162 [inline]
 __x64_sys_sendmsg+0x331/0x460 net/socket.c:2162
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: fdb694a ("netfilter: Add fail-open support")
Fixes: 829e17a ("[NETFILTER]: nfnetlink_queue: allow changing queue length through netlink")
Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: syzbot <[email protected]>
Signed-off-by: Pablo Neira Ayuso <[email protected]>
commodo pushed a commit that referenced this pull request Aug 7, 2018
Crash dump shows following instructions

crash> bt
PID: 0      TASK: ffffffffbe412480  CPU: 0   COMMAND: "swapper/0"
 #0 [ffff891ee0003868] machine_kexec at ffffffffbd063ef1
 #1 [ffff891ee00038c8] __crash_kexec at ffffffffbd12b6f2
 #2 [ffff891ee0003998] crash_kexec at ffffffffbd12c84c
 #3 [ffff891ee00039b8] oops_end at ffffffffbd030f0a
 #4 [ffff891ee00039e0] no_context at ffffffffbd074643
 #5 [ffff891ee0003a40] __bad_area_nosemaphore at ffffffffbd07496e
 #6 [ffff891ee0003a90] bad_area_nosemaphore at ffffffffbd074a64
 #7 [ffff891ee0003aa0] __do_page_fault at ffffffffbd074b0a
 #8 [ffff891ee0003b18] do_page_fault at ffffffffbd074fc8
 #9 [ffff891ee0003b50] page_fault at ffffffffbda01925
    [exception RIP: qlt_schedule_sess_for_deletion+15]
    RIP: ffffffffc02e526f  RSP: ffff891ee0003c08  RFLAGS: 00010046
    RAX: 0000000000000000  RBX: 0000000000000000  RCX: ffffffffc0307847
    RDX: 00000000000020e6  RSI: ffff891edbc377c8  RDI: 0000000000000000
    RBP: ffff891ee0003c18   R8: ffffffffc02f0b20   R9: 0000000000000250
    R10: 0000000000000258  R11: 000000000000b780  R12: ffff891ed9b43000
    R13: 00000000000000f0  R14: 0000000000000006  R15: ffff891edbc377c8
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #10 [ffff891ee0003c20] qla2x00_fcport_event_handler at ffffffffc02853d3 [qla2xxx]
 #11 [ffff891ee0003cf0] __dta_qla24xx_async_gnl_sp_done_333 at ffffffffc0285a1d [qla2xxx]
 #12 [ffff891ee0003de8] qla24xx_process_response_queue at ffffffffc02a2eb5 [qla2xxx]
 #13 [ffff891ee0003e88] qla24xx_msix_rsp_q at ffffffffc02a5403 [qla2xxx]
 #14 [ffff891ee0003ec0] __handle_irq_event_percpu at ffffffffbd0f4c59
 #15 [ffff891ee0003f10] handle_irq_event_percpu at ffffffffbd0f4e02
 #16 [ffff891ee0003f40] handle_irq_event at ffffffffbd0f4e90
 #17 [ffff891ee0003f68] handle_edge_irq at ffffffffbd0f8984
 #18 [ffff891ee0003f88] handle_irq at ffffffffbd0305d5
 #19 [ffff891ee0003fb8] do_IRQ at ffffffffbda02a18
 --- <IRQ stack> ---
 #20 [ffffffffbe403d30] ret_from_intr at ffffffffbda0094e
    [exception RIP: unknown or invalid address]
    RIP: 000000000000001f  RSP: 0000000000000000  RFLAGS: fff3b8c2091ebb3f
    RAX: ffffbba5a0000200  RBX: 0000be8cdfa8f9fa  RCX: 0000000000000018
    RDX: 0000000000000101  RSI: 000000000000015d  RDI: 0000000000000193
    RBP: 0000000000000083   R8: ffffffffbe403e38   R9: 0000000000000002
    R10: 0000000000000000  R11: ffffffffbe56b820  R12: ffff891ee001cf00
    R13: ffffffffbd11c0a4  R14: ffffffffbe403d60  R15: 0000000000000001
    ORIG_RAX: ffff891ee0022ac0  CS: 0000  SS: ffffffffffffffb9
 bt: WARNING: possibly bogus exception frame
 #21 [ffffffffbe403dd8] cpuidle_enter_state at ffffffffbd67c6fd
 #22 [ffffffffbe403e40] cpuidle_enter at ffffffffbd67c907
 #23 [ffffffffbe403e50] call_cpuidle at ffffffffbd0d98f3
 #24 [ffffffffbe403e60] do_idle at ffffffffbd0d9b42
 #25 [ffffffffbe403e98] cpu_startup_entry at ffffffffbd0d9da3
 #26 [ffffffffbe403ec0] rest_init at ffffffffbd81d4aa
 #27 [ffffffffbe403ed0] start_kernel at ffffffffbe67d2ca
 #28 [ffffffffbe403f28] x86_64_start_reservations at ffffffffbe67c675
 #29 [ffffffffbe403f38] x86_64_start_kernel at ffffffffbe67c6eb
 #30 [ffffffffbe403f50] secondary_startup_64 at ffffffffbd0000d5

Fixes: 040036b ("scsi: qla2xxx: Delay loop id allocation at login")
Cc: <[email protected]> # v4.17+
Signed-off-by: Chuck Anderson <[email protected]>
Signed-off-by: Himanshu Madhani <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
commodo pushed a commit that referenced this pull request Oct 2, 2019
This reverts commit 3342ce3, as there is no need for this separate
property and it breaks compatibility with existing devicetree files
(arch/arm64/boot/dts/freescale/imx8mq.dtsi).

CC: [email protected] #5.2
Fixes: 3342ce3 ("usb: usb251xb: Add US lanes inversion dts-bindings")
Signed-off-by: Lucas Stach <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
commodo pushed a commit that referenced this pull request Oct 2, 2019
This property isn't needed and not yet used anywhere. The swap-dx-lanes
property is perfectly fine for doing the swap on the upstream port
lanes.

CC: [email protected] #5.2
Signed-off-by: Lucas Stach <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
commodo pushed a commit that referenced this pull request Oct 2, 2019
This is a partial revert of 73d31de "usb: usb251xb: Create a ports
field collector method", which broke a existing devicetree
(arch/arm64/boot/dts/freescale/imx8mq.dtsi).

There is no reason why the swap-dx-lanes property should not apply to
the upstream port. The reason given in the breaking commit was that it's
inconsitent with respect to other port properties, but in fact it is not.
All other properties which only apply to the downstream ports explicitly
reject port 0, so there is pretty strong precedence that the driver
referred to the upstream port as port 0. So there is no inconsistency in
this property at all, other than the swapping being also applicable to
the upstream port.

CC: [email protected] #5.2
Signed-off-by: Lucas Stach <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
commodo pushed a commit that referenced this pull request Oct 2, 2019
A deadlock with this stacktrace was observed.

The loop thread does a GFP_KERNEL allocation, it calls into dm-bufio
shrinker and the shrinker depends on I/O completion in the dm-bufio
subsystem.

In order to fix the deadlock (and other similar ones), we set the flag
PF_MEMALLOC_NOIO at loop thread entry.

PID: 474    TASK: ffff8813e11f4600  CPU: 10  COMMAND: "kswapd0"
   #0 [ffff8813dedfb938] __schedule at ffffffff8173f405
   #1 [ffff8813dedfb990] schedule at ffffffff8173fa27
   #2 [ffff8813dedfb9b0] schedule_timeout at ffffffff81742fec
   #3 [ffff8813dedfba60] io_schedule_timeout at ffffffff8173f186
   #4 [ffff8813dedfbaa0] bit_wait_io at ffffffff8174034f
   #5 [ffff8813dedfbac0] __wait_on_bit at ffffffff8173fec8
   #6 [ffff8813dedfbb10] out_of_line_wait_on_bit at ffffffff8173ff81
   #7 [ffff8813dedfbb90] __make_buffer_clean at ffffffffa038736f [dm_bufio]
   #8 [ffff8813dedfbbb0] __try_evict_buffer at ffffffffa0387bb8 [dm_bufio]
   #9 [ffff8813dedfbbd0] dm_bufio_shrink_scan at ffffffffa0387cc3 [dm_bufio]
  #10 [ffff8813dedfbc40] shrink_slab at ffffffff811a87ce
  #11 [ffff8813dedfbd30] shrink_zone at ffffffff811ad778
  #12 [ffff8813dedfbdc0] kswapd at ffffffff811ae92f
  #13 [ffff8813dedfbec0] kthread at ffffffff810a8428
  #14 [ffff8813dedfbf50] ret_from_fork at ffffffff81745242

  PID: 14127  TASK: ffff881455749c00  CPU: 11  COMMAND: "loop1"
   #0 [ffff88272f5af228] __schedule at ffffffff8173f405
   #1 [ffff88272f5af280] schedule at ffffffff8173fa27
   #2 [ffff88272f5af2a0] schedule_preempt_disabled at ffffffff8173fd5e
   #3 [ffff88272f5af2b0] __mutex_lock_slowpath at ffffffff81741fb5
   #4 [ffff88272f5af330] mutex_lock at ffffffff81742133
   #5 [ffff88272f5af350] dm_bufio_shrink_count at ffffffffa03865f9 [dm_bufio]
   #6 [ffff88272f5af380] shrink_slab at ffffffff811a86bd
   #7 [ffff88272f5af470] shrink_zone at ffffffff811ad778
   #8 [ffff88272f5af500] do_try_to_free_pages at ffffffff811adb34
   #9 [ffff88272f5af590] try_to_free_pages at ffffffff811adef8
  #10 [ffff88272f5af610] __alloc_pages_nodemask at ffffffff811a09c3
  #11 [ffff88272f5af710] alloc_pages_current at ffffffff811e8b71
  #12 [ffff88272f5af760] new_slab at ffffffff811f4523
  #13 [ffff88272f5af7b0] __slab_alloc at ffffffff8173a1b5
  #14 [ffff88272f5af880] kmem_cache_alloc at ffffffff811f484b
  #15 [ffff88272f5af8d0] do_blockdev_direct_IO at ffffffff812535b3
  #16 [ffff88272f5afb00] __blockdev_direct_IO at ffffffff81255dc3
  #17 [ffff88272f5afb30] xfs_vm_direct_IO at ffffffffa01fe3fc [xfs]
  #18 [ffff88272f5afb90] generic_file_read_iter at ffffffff81198994
  #19 [ffff88272f5afc50] __dta_xfs_file_read_iter_2398 at ffffffffa020c970 [xfs]
  #20 [ffff88272f5afcc0] lo_rw_aio at ffffffffa0377042 [loop]
  #21 [ffff88272f5afd70] loop_queue_work at ffffffffa0377c3b [loop]
  #22 [ffff88272f5afe60] kthread_worker_fn at ffffffff810a8a0c
  #23 [ffff88272f5afec0] kthread at ffffffff810a8428
  #24 [ffff88272f5aff50] ret_from_fork at ffffffff81745242

Signed-off-by: Mikulas Patocka <[email protected]>
Cc: [email protected]
Signed-off-by: Jens Axboe <[email protected]>
commodo pushed a commit that referenced this pull request Nov 21, 2019
When the function name for an inline frame is invalid, we must not try
to demangle this symbol, otherwise we crash with:

  #0  0x0000555555895c01 in bfd_demangle ()
  #1  0x0000555555823262 in demangle_sym (dso=0x555555d92b90, elf_name=0x0, kmodule=0) at util/symbol-elf.c:215
  #2  dso__demangle_sym (dso=dso@entry=0x555555d92b90, kmodule=<optimized out>, kmodule@entry=0, elf_name=elf_name@entry=0x0) at util/symbol-elf.c:400
  #3  0x00005555557fef4b in new_inline_sym (funcname=0x0, base_sym=0x555555d92b90, dso=0x555555d92b90) at util/srcline.c:89
  #4  inline_list__append_dso_a2l (dso=dso@entry=0x555555c7bb00, node=node@entry=0x555555e31810, sym=sym@entry=0x555555d92b90) at util/srcline.c:264
  #5  0x00005555557ff27f in addr2line (dso_name=dso_name@entry=0x555555d92430 "/home/milian/.debug/.build-id/f7/186d14bb94f3c6161c010926da66033d24fce5/elf", addr=addr@entry=2888, file=file@entry=0x0,
      line=line@entry=0x0, dso=dso@entry=0x555555c7bb00, unwind_inlines=unwind_inlines@entry=true, node=0x555555e31810, sym=0x555555d92b90) at util/srcline.c:313
  #6  0x00005555557ffe7c in addr2inlines (sym=0x555555d92b90, dso=0x555555c7bb00, addr=2888, dso_name=0x555555d92430 "/home/milian/.debug/.build-id/f7/186d14bb94f3c6161c010926da66033d24fce5/elf")
      at util/srcline.c:358

So instead handle the case where we get invalid function names for
inlined frames and use a fallback '??' function name instead.

While this crash was originally reported by Hadrien for rust code, I can
now also reproduce it with trivial C++ code. Indeed, it seems like
libbfd fails to interpret the debug information for the inline frame
symbol name:

  $ addr2line -e /home/milian/.debug/.build-id/f7/186d14bb94f3c6161c010926da66033d24fce5/elf -if b48
  main
  /usr/include/c++/8.2.1/complex:610
  ??
  /usr/include/c++/8.2.1/complex:618
  ??
  /usr/include/c++/8.2.1/complex:675
  ??
  /usr/include/c++/8.2.1/complex:685
  main
  /home/milian/projects/kdab/rnd/hotspot/tests/test-clients/cpp-inlining/main.cpp:39

I've reported this bug upstream and also attached a patch there which
should fix this issue:

https://sourceware.org/bugzilla/show_bug.cgi?id=23715

Reported-by: Hadrien Grasland <[email protected]>
Signed-off-by: Milian Wolff <[email protected]>
Cc: Jin Yao <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Fixes: a64489c ("perf report: Find the inline stack for a given address")
[ The above 'Fixes:' cset is where originally the problem was
  introduced, i.e.  using a2l->funcname without checking if it is NULL,
  but this current patch fixes the current codebase, i.e. multiple csets
  were applied after a64489c before the problem was reported by Hadrien ]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
commodo pushed a commit that referenced this pull request Nov 25, 2019
The baseboard of the Logic PD i.MX6 development kit has a power
button routed which can both power down and power up the board.
It can also wake the board from sleep.  This functionality was
marked as disabled by default in imx6qdl.dtsi, so it needs to
be explicitly enabled for each board.

This patch enables the snvs power key again.

Signed-off-by: Adam Ford <[email protected]>
Fixes: 770856f ("ARM: dts: imx6qdl: Enable SNVS power key according to board design")
Cc: stable <[email protected]> #5.3+
Signed-off-by: Shawn Guo <[email protected]>
commodo pushed a commit that referenced this pull request Aug 27, 2020
mm->tlb_flush_batched could be accessed concurrently as noticed by
KCSAN,

 BUG: KCSAN: data-race in flush_tlb_batched_pending / try_to_unmap_one

 write to 0xffff93f754880bd0 of 1 bytes by task 822 on cpu 6:
  try_to_unmap_one+0x59a/0x1ab0
  set_tlb_ubc_flush_pending at mm/rmap.c:635
  (inlined by) try_to_unmap_one at mm/rmap.c:1538
  rmap_walk_anon+0x296/0x650
  rmap_walk+0xdf/0x100
  try_to_unmap+0x18a/0x2f0
  shrink_page_list+0xef6/0x2870
  shrink_inactive_list+0x316/0x880
  shrink_lruvec+0x8dc/0x1380
  shrink_node+0x317/0xd80
  balance_pgdat+0x652/0xd90
  kswapd+0x396/0x8d0
  kthread+0x1e0/0x200
  ret_from_fork+0x27/0x50

 read to 0xffff93f754880bd0 of 1 bytes by task 6364 on cpu 4:
  flush_tlb_batched_pending+0x29/0x90
  flush_tlb_batched_pending at mm/rmap.c:682
  change_p4d_range+0x5dd/0x1030
  change_pte_range at mm/mprotect.c:44
  (inlined by) change_pmd_range at mm/mprotect.c:212
  (inlined by) change_pud_range at mm/mprotect.c:240
  (inlined by) change_p4d_range at mm/mprotect.c:260
  change_protection+0x222/0x310
  change_prot_numa+0x3e/0x60
  task_numa_work+0x219/0x350
  task_work_run+0xed/0x140
  prepare_exit_to_usermode+0x2cc/0x2e0
  ret_from_intr+0x32/0x42

 Reported by Kernel Concurrency Sanitizer on:
 CPU: 4 PID: 6364 Comm: mtest01 Tainted: G        W    L 5.5.0-next-20200210+ #5
 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019

flush_tlb_batched_pending() is under PTL but the write is not, but
mm->tlb_flush_batched is only a bool type, so the value is unlikely to be
shattered.  Thus, mark it as an intentional data race by using the data
race macro.

Signed-off-by: Qian Cai <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Marco Elver <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
commodo pushed a commit that referenced this pull request Sep 10, 2020
I got the following lockdep splat while testing:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.8.0-rc7-00172-g021118712e59 #932 Not tainted
  ------------------------------------------------------
  btrfs/229626 is trying to acquire lock:
  ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450

  but task is already holding lock:
  ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 btrfs_scrub_dev+0x11c/0x630
	 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4
	 btrfs_ioctl+0x2799/0x30a0
	 ksys_ioctl+0x83/0xc0
	 __x64_sys_ioctl+0x16/0x20
	 do_syscall_64+0x50/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 btrfs_run_dev_stats+0x49/0x480
	 commit_cowonly_roots+0xb5/0x2a0
	 btrfs_commit_transaction+0x516/0xa60
	 sync_filesystem+0x6b/0x90
	 generic_shutdown_super+0x22/0x100
	 kill_anon_super+0xe/0x30
	 btrfs_kill_super+0x12/0x20
	 deactivate_locked_super+0x29/0x60
	 cleanup_mnt+0xb8/0x140
	 task_work_run+0x6d/0xb0
	 __prepare_exit_to_usermode+0x1cc/0x1e0
	 do_syscall_64+0x5c/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 btrfs_commit_transaction+0x4bb/0xa60
	 sync_filesystem+0x6b/0x90
	 generic_shutdown_super+0x22/0x100
	 kill_anon_super+0xe/0x30
	 btrfs_kill_super+0x12/0x20
	 deactivate_locked_super+0x29/0x60
	 cleanup_mnt+0xb8/0x140
	 task_work_run+0x6d/0xb0
	 __prepare_exit_to_usermode+0x1cc/0x1e0
	 do_syscall_64+0x5c/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 btrfs_record_root_in_trans+0x43/0x70
	 start_transaction+0xd1/0x5d0
	 btrfs_dirty_inode+0x42/0xd0
	 touch_atime+0xa1/0xd0
	 btrfs_file_mmap+0x3f/0x60
	 mmap_region+0x3a4/0x640
	 do_mmap+0x376/0x580
	 vm_mmap_pgoff+0xd5/0x120
	 ksys_mmap_pgoff+0x193/0x230
	 do_syscall_64+0x50/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #3 (&mm->mmap_lock#2){++++}-{3:3}:
	 __might_fault+0x68/0x90
	 _copy_to_user+0x1e/0x80
	 perf_read+0x141/0x2c0
	 vfs_read+0xad/0x1b0
	 ksys_read+0x5f/0xe0
	 do_syscall_64+0x50/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #2 (&cpuctx_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 perf_event_init_cpu+0x88/0x150
	 perf_event_init+0x1db/0x20b
	 start_kernel+0x3ae/0x53c
	 secondary_startup_64+0xa4/0xb0

  -> #1 (pmus_lock){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 perf_event_init_cpu+0x4f/0x150
	 cpuhp_invoke_callback+0xb1/0x900
	 _cpu_up.constprop.26+0x9f/0x130
	 cpu_up+0x7b/0xc0
	 bringup_nonboot_cpus+0x4f/0x60
	 smp_init+0x26/0x71
	 kernel_init_freeable+0x110/0x258
	 kernel_init+0xa/0x103
	 ret_from_fork+0x1f/0x30

  -> #0 (cpu_hotplug_lock){++++}-{0:0}:
	 __lock_acquire+0x1272/0x2310
	 lock_acquire+0x9e/0x360
	 cpus_read_lock+0x39/0xb0
	 alloc_workqueue+0x378/0x450
	 __btrfs_alloc_workqueue+0x15d/0x200
	 btrfs_alloc_workqueue+0x51/0x160
	 scrub_workers_get+0x5a/0x170
	 btrfs_scrub_dev+0x18c/0x630
	 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4
	 btrfs_ioctl+0x2799/0x30a0
	 ksys_ioctl+0x83/0xc0
	 __x64_sys_ioctl+0x16/0x20
	 do_syscall_64+0x50/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  other info that might help us debug this:

  Chain exists of:
    cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(&fs_info->scrub_lock);
				 lock(&fs_devs->device_list_mutex);
				 lock(&fs_info->scrub_lock);
    lock(cpu_hotplug_lock);

   *** DEADLOCK ***

  2 locks held by btrfs/229626:
   #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630
   #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630

  stack backtrace:
  CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932
  Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018
  Call Trace:
   dump_stack+0x78/0xa0
   check_noncircular+0x165/0x180
   __lock_acquire+0x1272/0x2310
   lock_acquire+0x9e/0x360
   ? alloc_workqueue+0x378/0x450
   cpus_read_lock+0x39/0xb0
   ? alloc_workqueue+0x378/0x450
   alloc_workqueue+0x378/0x450
   ? rcu_read_lock_sched_held+0x52/0x80
   __btrfs_alloc_workqueue+0x15d/0x200
   btrfs_alloc_workqueue+0x51/0x160
   scrub_workers_get+0x5a/0x170
   btrfs_scrub_dev+0x18c/0x630
   ? start_transaction+0xd1/0x5d0
   btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4
   btrfs_ioctl+0x2799/0x30a0
   ? do_sigaction+0x102/0x250
   ? lockdep_hardirqs_on_prepare+0xca/0x160
   ? _raw_spin_unlock_irq+0x24/0x30
   ? trace_hardirqs_on+0x1c/0xe0
   ? _raw_spin_unlock_irq+0x24/0x30
   ? do_sigaction+0x102/0x250
   ? ksys_ioctl+0x83/0xc0
   ksys_ioctl+0x83/0xc0
   __x64_sys_ioctl+0x16/0x20
   do_syscall_64+0x50/0x90
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

This happens because we're allocating the scrub workqueues under the
scrub and device list mutex, which brings in a whole host of other
dependencies.

Because the work queue allocation is done with GFP_KERNEL, it can
trigger reclaim, which can lead to a transaction commit, which in turns
needs the device_list_mutex, it can lead to a deadlock. A different
problem for which this fix is a solution.

Fix this by moving the actual allocation outside of the
scrub lock, and then only take the lock once we're ready to actually
assign them to the fs_info.  We'll now have to cleanup the workqueues in
a few more places, so I've added a helper to do the refcount dance to
safely free the workqueues.

CC: [email protected] # 5.4+
Reviewed-by: Filipe Manana <[email protected]>
Signed-off-by: Josef Bacik <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>
commodo pushed a commit that referenced this pull request Sep 10, 2020
…s metrics" test

Linux 5.9 introduced perf test case "Parse and process metrics" and
on s390 this test case always dumps core:

  [root@t35lp67 perf]# ./perf test -vvvv -F 67
  67: Parse and process metrics                             :
  --- start ---
  metric expr inst_retired.any / cpu_clk_unhalted.thread for IPC
  parsing metric: inst_retired.any / cpu_clk_unhalted.thread
  Segmentation fault (core dumped)
  [root@t35lp67 perf]#

I debugged this core dump and gdb shows this call chain:

  (gdb) where
   #0  0x000003ffabc3192a in __strnlen_c_1 () from /lib64/libc.so.6
   #1  0x000003ffabc293de in strcasestr () from /lib64/libc.so.6
   #2  0x0000000001102ba2 in match_metric(list=0x1e6ea20 "inst_retired.any",
            n=<optimized out>)
       at util/metricgroup.c:368
   #3  find_metric (map=<optimized out>, map=<optimized out>,
           metric=0x1e6ea20 "inst_retired.any")
      at util/metricgroup.c:765
   #4  __resolve_metric (ids=0x0, map=<optimized out>, metric_list=0x0,
           metric_no_group=<optimized out>, m=<optimized out>)
      at util/metricgroup.c:844
   #5  resolve_metric (ids=0x0, map=0x0, metric_list=0x0,
          metric_no_group=<optimized out>)
      at util/metricgroup.c:881
   #6  metricgroup__add_metric (metric=<optimized out>,
        metric_no_group=metric_no_group@entry=false, events=<optimized out>,
        events@entry=0x3ffd84fb878, metric_list=0x0,
        metric_list@entry=0x3ffd84fb868, map=0x0)
      at util/metricgroup.c:943
   #7  0x00000000011034ae in metricgroup__add_metric_list (map=0x13f9828 <map>,
        metric_list=0x3ffd84fb868, events=0x3ffd84fb878,
        metric_no_group=<optimized out>, list=<optimized out>)
      at util/metricgroup.c:988
   #8  parse_groups (perf_evlist=perf_evlist@entry=0x1e70260,
          str=str@entry=0x12f34b2 "IPC", metric_no_group=<optimized out>,
          metric_no_merge=<optimized out>,
          fake_pmu=fake_pmu@entry=0x1462f18 <perf_pmu.fake>,
          metric_events=0x3ffd84fba58, map=0x1)
      at util/metricgroup.c:1040
   #9  0x0000000001103eb2 in metricgroup__parse_groups_test(
  	evlist=evlist@entry=0x1e70260, map=map@entry=0x13f9828 <map>,
  	str=str@entry=0x12f34b2 "IPC",
  	metric_no_group=metric_no_group@entry=false,
  	metric_no_merge=metric_no_merge@entry=false,
  	metric_events=0x3ffd84fba58)
      at util/metricgroup.c:1082
   #10 0x00000000010c84d8 in __compute_metric (ratio2=0x0, name2=0x0,
          ratio1=<synthetic pointer>, name1=0x12f34b2 "IPC",
  	vals=0x3ffd84fbad8, name=0x12f34b2 "IPC")
      at tests/parse-metric.c:159
   #11 compute_metric (ratio=<synthetic pointer>, vals=0x3ffd84fbad8,
  	name=0x12f34b2 "IPC")
      at tests/parse-metric.c:189
   #12 test_ipc () at tests/parse-metric.c:208
.....
..... omitted many more lines

This test case was added with
commit 218ca91 ("perf tests: Add parse metric test for frontend metric").

When I compile with make DEBUG=y it works fine and I do not get a core dump.

It turned out that the above listed function call chain worked on a struct
pmu_event array which requires a trailing element with zeroes which was
missing. The marco map_for_each_event() loops over that array tests for members
metric_expr/metric_name/metric_group being non-NULL. Adding this element fixes
the issue.

Output after:

  [root@t35lp46 perf]# ./perf test 67
  67: Parse and process metrics                             : Ok
  [root@t35lp46 perf]#

Committer notes:

As Ian remarks, this is not s390 specific:

<quote Ian>
  This also shows up with address sanitizer on all architectures
  (perhaps change the patch title) and perhaps add a "Fixes: <commit>"
  tag.

  =================================================================
  ==4718==ERROR: AddressSanitizer: global-buffer-overflow on address
  0x55c93b4d59e8 at pc 0x55c93a1541e2 bp 0x7ffd24327c60 sp
  0x7ffd24327c58
  READ of size 8 at 0x55c93b4d59e8 thread T0
      #0 0x55c93a1541e1 in find_metric tools/perf/util/metricgroup.c:764:2
      #1 0x55c93a153e6c in __resolve_metric tools/perf/util/metricgroup.c:844:9
      #2 0x55c93a152f18 in resolve_metric tools/perf/util/metricgroup.c:881:9
      #3 0x55c93a1528db in metricgroup__add_metric
  tools/perf/util/metricgroup.c:943:9
      #4 0x55c93a151996 in metricgroup__add_metric_list
  tools/perf/util/metricgroup.c:988:9
      #5 0x55c93a1511b9 in parse_groups tools/perf/util/metricgroup.c:1040:8
      #6 0x55c93a1513e1 in metricgroup__parse_groups_test
  tools/perf/util/metricgroup.c:1082:9
      #7 0x55c93a0108ae in __compute_metric tools/perf/tests/parse-metric.c:159:8
      #8 0x55c93a010744 in compute_metric tools/perf/tests/parse-metric.c:189:9
      #9 0x55c93a00f5ee in test_ipc tools/perf/tests/parse-metric.c:208:2
      #10 0x55c93a00f1e8 in test__parse_metric
  tools/perf/tests/parse-metric.c:345:2
      #11 0x55c939fd7202 in run_test tools/perf/tests/builtin-test.c:410:9
      #12 0x55c939fd6736 in test_and_print tools/perf/tests/builtin-test.c:440:9
      #13 0x55c939fd58c3 in __cmd_test tools/perf/tests/builtin-test.c:661:4
      #14 0x55c939fd4e02 in cmd_test tools/perf/tests/builtin-test.c:807:9
      #15 0x55c939e4763d in run_builtin tools/perf/perf.c:313:11
      #16 0x55c939e46475 in handle_internal_command tools/perf/perf.c:365:8
      #17 0x55c939e4737e in run_argv tools/perf/perf.c:409:2
      #18 0x55c939e45f7e in main tools/perf/perf.c:539:3

  0x55c93b4d59e8 is located 0 bytes to the right of global variable
  'pme_test' defined in 'tools/perf/tests/parse-metric.c:17:25'
  (0x55c93b4d54a0) of size 1352
  SUMMARY: AddressSanitizer: global-buffer-overflow
  tools/perf/util/metricgroup.c:764:2 in find_metric
  Shadow bytes around the buggy address:
    0x0ab9a7692ae0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    0x0ab9a7692af0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    0x0ab9a7692b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    0x0ab9a7692b10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    0x0ab9a7692b20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  =>0x0ab9a7692b30: 00 00 00 00 00 00 00 00 00 00 00 00 00[f9]f9 f9
    0x0ab9a7692b40: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
    0x0ab9a7692b50: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
    0x0ab9a7692b60: f9 f9 f9 f9 f9 f9 f9 f9 00 00 00 00 00 00 00 00
    0x0ab9a7692b70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    0x0ab9a7692b80: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
  Shadow byte legend (one shadow byte represents 8 application bytes):
    Addressable:           00
    Partially addressable: 01 02 03 04 05 06 07
    Heap left redzone:	   fa
    Freed heap region:	   fd
    Stack left redzone:	   f1
    Stack mid redzone:	   f2
    Stack right redzone:     f3
    Stack after return:	   f5
    Stack use after scope:   f8
    Global redzone:          f9
    Global init order:	   f6
    Poisoned by user:        f7
    Container overflow:	   fc
    Array cookie:            ac
    Intra object redzone:    bb
    ASan internal:           fe
    Left alloca redzone:     ca
    Right alloca redzone:    cb
    Shadow gap:              cc
</quote>

I'm also adding the missing "Fixes" tag and setting just .name to NULL,
as doing it that way is more compact (the compiler will zero out
everything else) and the table iterators look for .name being NULL as
the sentinel marking the end of the table.

Fixes: 0a507af ("perf tests: Add parse metric test for ipc metric")
Signed-off-by: Thomas Richter <[email protected]>
Reviewed-by: Sumanth Korikkar <[email protected]>
Acked-by: Ian Rogers <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
commodo pushed a commit that referenced this pull request Feb 19, 2021
Like other tunneling interfaces, the bareudp doesn't need TXLOCK.
So, It is good to set the NETIF_F_LLTX flag to improve performance and
to avoid lockdep's false-positive warning.

Test commands:
    ip netns add A
    ip netns add B
    ip link add veth0 netns A type veth peer name veth1 netns B
    ip netns exec A ip link set veth0 up
    ip netns exec A ip a a 10.0.0.1/24 dev veth0
    ip netns exec B ip link set veth1 up
    ip netns exec B ip a a 10.0.0.2/24 dev veth1

    for i in {2..1}
    do
            let A=$i-1
            ip netns exec A ip link add bareudp$i type bareudp \
		    dstport $i ethertype ip
            ip netns exec A ip link set bareudp$i up
            ip netns exec A ip a a 10.0.$i.1/24 dev bareudp$i
            ip netns exec A ip r a 10.0.$i.2 encap ip src 10.0.$A.1 \
		    dst 10.0.$A.2 via 10.0.$i.2 dev bareudp$i

            ip netns exec B ip link add bareudp$i type bareudp \
		    dstport $i ethertype ip
            ip netns exec B ip link set bareudp$i up
            ip netns exec B ip a a 10.0.$i.2/24 dev bareudp$i
            ip netns exec B ip r a 10.0.$i.1 encap ip src 10.0.$A.2 \
		    dst 10.0.$A.1 via 10.0.$i.1 dev bareudp$i
    done
    ip netns exec A ping 10.0.2.2

Splat looks like:
[   96.992803][  T822] ============================================
[   96.993954][  T822] WARNING: possible recursive locking detected
[   96.995102][  T822] 5.10.0+ #819 Not tainted
[   96.995927][  T822] --------------------------------------------
[   96.997091][  T822] ping/822 is trying to acquire lock:
[   96.998083][  T822] ffff88810f753898 (_xmit_NONE#2){+.-.}-{2:2}, at: __dev_queue_xmit+0x1f52/0x2960
[   96.999813][  T822]
[   96.999813][  T822] but task is already holding lock:
[   97.001192][  T822] ffff88810c385498 (_xmit_NONE#2){+.-.}-{2:2}, at: __dev_queue_xmit+0x1f52/0x2960
[   97.002908][  T822]
[   97.002908][  T822] other info that might help us debug this:
[   97.004401][  T822]  Possible unsafe locking scenario:
[   97.004401][  T822]
[   97.005784][  T822]        CPU0
[   97.006407][  T822]        ----
[   97.007010][  T822]   lock(_xmit_NONE#2);
[   97.007779][  T822]   lock(_xmit_NONE#2);
[   97.008550][  T822]
[   97.008550][  T822]  *** DEADLOCK ***
[   97.008550][  T822]
[   97.010057][  T822]  May be due to missing lock nesting notation
[   97.010057][  T822]
[   97.011594][  T822] 7 locks held by ping/822:
[   97.012426][  T822]  #0: ffff888109a144f0 (sk_lock-AF_INET){+.+.}-{0:0}, at: raw_sendmsg+0x12f7/0x2b00
[   97.014191][  T822]  #1: ffffffffbce2f5a0 (rcu_read_lock_bh){....}-{1:2}, at: ip_finish_output2+0x249/0x2020
[   97.016045][  T822]  #2: ffffffffbce2f5a0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1fd/0x2960
[   97.017897][  T822]  #3: ffff88810c385498 (_xmit_NONE#2){+.-.}-{2:2}, at: __dev_queue_xmit+0x1f52/0x2960
[   97.019684][  T822]  #4: ffffffffbce2f600 (rcu_read_lock){....}-{1:2}, at: bareudp_xmit+0x31b/0x3690 [bareudp]
[   97.021573][  T822]  #5: ffffffffbce2f5a0 (rcu_read_lock_bh){....}-{1:2}, at: ip_finish_output2+0x249/0x2020
[   97.023424][  T822]  #6: ffffffffbce2f5a0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1fd/0x2960
[   97.025259][  T822]
[   97.025259][  T822] stack backtrace:
[   97.026349][  T822] CPU: 3 PID: 822 Comm: ping Not tainted 5.10.0+ #819
[   97.027609][  T822] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
[   97.029407][  T822] Call Trace:
[   97.030015][  T822]  dump_stack+0x99/0xcb
[   97.030783][  T822]  __lock_acquire.cold.77+0x149/0x3a9
[   97.031773][  T822]  ? stack_trace_save+0x81/0xa0
[   97.032661][  T822]  ? register_lock_class+0x1910/0x1910
[   97.033673][  T822]  ? register_lock_class+0x1910/0x1910
[   97.034679][  T822]  ? rcu_read_lock_sched_held+0x91/0xc0
[   97.035697][  T822]  ? rcu_read_lock_bh_held+0xa0/0xa0
[   97.036690][  T822]  lock_acquire+0x1b2/0x730
[   97.037515][  T822]  ? __dev_queue_xmit+0x1f52/0x2960
[   97.038466][  T822]  ? check_flags+0x50/0x50
[   97.039277][  T822]  ? netif_skb_features+0x296/0x9c0
[   97.040226][  T822]  ? validate_xmit_skb+0x29/0xb10
[   97.041151][  T822]  _raw_spin_lock+0x30/0x70
[   97.041977][  T822]  ? __dev_queue_xmit+0x1f52/0x2960
[   97.042927][  T822]  __dev_queue_xmit+0x1f52/0x2960
[   97.043852][  T822]  ? netdev_core_pick_tx+0x290/0x290
[   97.044824][  T822]  ? mark_held_locks+0xb7/0x120
[   97.045712][  T822]  ? lockdep_hardirqs_on_prepare+0x12c/0x3e0
[   97.046824][  T822]  ? __local_bh_enable_ip+0xa5/0xf0
[   97.047771][  T822]  ? ___neigh_create+0x12a8/0x1eb0
[   97.048710][  T822]  ? trace_hardirqs_on+0x41/0x120
[   97.049626][  T822]  ? ___neigh_create+0x12a8/0x1eb0
[   97.050556][  T822]  ? __local_bh_enable_ip+0xa5/0xf0
[   97.051509][  T822]  ? ___neigh_create+0x12a8/0x1eb0
[   97.052443][  T822]  ? check_chain_key+0x244/0x5f0
[   97.053352][  T822]  ? rcu_read_lock_bh_held+0x56/0xa0
[   97.054317][  T822]  ? ip_finish_output2+0x6ea/0x2020
[   97.055263][  T822]  ? pneigh_lookup+0x410/0x410
[   97.056135][  T822]  ip_finish_output2+0x6ea/0x2020
[ ... ]

Acked-by: Guillaume Nault <[email protected]>
Fixes: 571912c ("net: UDP tunnel encapsulation module for tunnelling different protocols like MPLS, IP, NSH etc.")
Signed-off-by: Taehee Yoo <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
commodo pushed a commit that referenced this pull request Feb 19, 2021
KASAN detect following BUG:
[  778.215311] ==================================================================
[  778.216696] BUG: KASAN: use-after-free in rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[  778.219037] Read of size 8 at addr ffff88b1d6516c28 by task tee/8842

[  778.220500] CPU: 37 PID: 8842 Comm: tee Kdump: loaded Not tainted 5.10.0-pserver #5.10.0-1+feature+linux+next+20201214.1025+0910d71
[  778.220529] Hardware name: Supermicro Super Server/X11DDW-L, BIOS 3.3 02/21/2020
[  778.220555] Call Trace:
[  778.220609]  dump_stack+0x99/0xcb
[  778.220667]  ? rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[  778.220715]  print_address_description.constprop.7+0x1e/0x230
[  778.220750]  ? freeze_kernel_threads+0x73/0x73
[  778.220896]  ? rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[  778.220932]  ? rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[  778.220994]  kasan_report.cold.9+0x37/0x7c
[  778.221066]  ? kobject_put+0x80/0x270
[  778.221102]  ? rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[  778.221184]  rnbd_srv_sess_dev_force_close+0x38/0x60 [rnbd_server]
[  778.221240]  rnbd_srv_dev_session_force_close_store+0x6a/0xc0 [rnbd_server]
[  778.221304]  ? sysfs_file_ops+0x90/0x90
[  778.221353]  kernfs_fop_write+0x141/0x240
[  778.221451]  vfs_write+0x142/0x4d0
[  778.221553]  ksys_write+0xc0/0x160
[  778.221602]  ? __ia32_sys_read+0x50/0x50
[  778.221684]  ? lockdep_hardirqs_on_prepare+0x13d/0x210
[  778.221718]  ? syscall_enter_from_user_mode+0x1c/0x50
[  778.221821]  do_syscall_64+0x33/0x40
[  778.221862]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  778.221896] RIP: 0033:0x7f4affdd9504
[  778.221928] Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 48 8d 05 f9 61 0d 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 41 54 49 89 d4 55 48 89 f5 53
[  778.221956] RSP: 002b:00007fffebb36b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[  778.222011] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f4affdd9504
[  778.222038] RDX: 0000000000000002 RSI: 00007fffebb36c50 RDI: 0000000000000003
[  778.222066] RBP: 00007fffebb36c50 R08: 0000556a151aa600 R09: 00007f4affeb1540
[  778.222094] R10: fffffffffffffc19 R11: 0000000000000246 R12: 0000556a151aa520
[  778.222121] R13: 0000000000000002 R14: 00007f4affea6760 R15: 0000000000000002

[  778.222764] Allocated by task 3212:
[  778.223285]  kasan_save_stack+0x19/0x40
[  778.223316]  __kasan_kmalloc.constprop.7+0xc1/0xd0
[  778.223347]  kmem_cache_alloc_trace+0x186/0x350
[  778.223382]  rnbd_srv_rdma_ev+0xf16/0x1690 [rnbd_server]
[  778.223422]  process_io_req+0x4d1/0x670 [rtrs_server]
[  778.223573]  __ib_process_cq+0x10a/0x350 [ib_core]
[  778.223709]  ib_cq_poll_work+0x31/0xb0 [ib_core]
[  778.223743]  process_one_work+0x521/0xa90
[  778.223773]  worker_thread+0x65/0x5b0
[  778.223802]  kthread+0x1f2/0x210
[  778.223833]  ret_from_fork+0x22/0x30

[  778.224296] Freed by task 8842:
[  778.224800]  kasan_save_stack+0x19/0x40
[  778.224829]  kasan_set_track+0x1c/0x30
[  778.224860]  kasan_set_free_info+0x1b/0x30
[  778.224889]  __kasan_slab_free+0x108/0x150
[  778.224919]  slab_free_freelist_hook+0x64/0x190
[  778.224947]  kfree+0xe2/0x650
[  778.224982]  rnbd_destroy_sess_dev+0x2fa/0x3b0 [rnbd_server]
[  778.225011]  kobject_put+0xda/0x270
[  778.225046]  rnbd_srv_sess_dev_force_close+0x30/0x60 [rnbd_server]
[  778.225081]  rnbd_srv_dev_session_force_close_store+0x6a/0xc0 [rnbd_server]
[  778.225111]  kernfs_fop_write+0x141/0x240
[  778.225140]  vfs_write+0x142/0x4d0
[  778.225169]  ksys_write+0xc0/0x160
[  778.225198]  do_syscall_64+0x33/0x40
[  778.225227]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

[  778.226506] The buggy address belongs to the object at ffff88b1d6516c00
                which belongs to the cache kmalloc-512 of size 512
[  778.227464] The buggy address is located 40 bytes inside of
                512-byte region [ffff88b1d6516c00, ffff88b1d6516e00)

The problem is in the sess_dev release function we call
rnbd_destroy_sess_dev, and could free the sess_dev already, but we still
set the keep_id in rnbd_srv_sess_dev_force_close, which lead to use
after free.

To fix it, move the keep_id before the sysfs removal, and cache the
rnbd_srv_session for lock accessing,

Fixes: 7869980 ("block/rnbd-srv: close a mapped device from server side.")
Signed-off-by: Jack Wang <[email protected]>
Reviewed-by: Guoqing Jiang <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
commodo pushed a commit that referenced this pull request Feb 19, 2021
Since dynamically allocate sglist is used for rnbd_iu, we can't free sg
table after send_usr_msg since the callback function (cqe.done) could
still access the sglist.

Otherwise KASAN reports UAF issue:

[ 4856.600257] BUG: KASAN: use-after-free in dma_direct_unmap_sg+0x53/0x290
[ 4856.600772] Read of size 4 at addr ffff888206af3a98 by task swapper/1/0

[ 4856.601729] CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: G        W         5.10.0-pserver #5.10.0-1+feature+linux+next+20201214.1025+0910d71
[ 4856.601748] Hardware name: Supermicro Super Server/X11DDW-L, BIOS 3.3 02/21/2020
[ 4856.601766] Call Trace:
[ 4856.601785]  <IRQ>
[ 4856.601822]  dump_stack+0x99/0xcb
[ 4856.601856]  ? dma_direct_unmap_sg+0x53/0x290
[ 4856.601888]  print_address_description.constprop.7+0x1e/0x230
[ 4856.601913]  ? freeze_kernel_threads+0x73/0x73
[ 4856.601965]  ? mark_held_locks+0x29/0xa0
[ 4856.602019]  ? dma_direct_unmap_sg+0x53/0x290
[ 4856.602039]  ? dma_direct_unmap_sg+0x53/0x290
[ 4856.602079]  kasan_report.cold.9+0x37/0x7c
[ 4856.602188]  ? mlx5_ib_post_recv+0x430/0x520 [mlx5_ib]
[ 4856.602209]  ? dma_direct_unmap_sg+0x53/0x290
[ 4856.602256]  dma_direct_unmap_sg+0x53/0x290
[ 4856.602366]  complete_rdma_req+0x188/0x4b0 [rtrs_client]
[ 4856.602451]  ? rtrs_clt_close+0x80/0x80 [rtrs_client]
[ 4856.602535]  ? mlx5_ib_poll_cq+0x48b/0x16e0 [mlx5_ib]
[ 4856.602589]  ? radix_tree_insert+0x3a0/0x3a0
[ 4856.602610]  ? do_raw_spin_lock+0x119/0x1d0
[ 4856.602647]  ? rwlock_bug.part.1+0x60/0x60
[ 4856.602740]  rtrs_clt_rdma_done+0x3f7/0x670 [rtrs_client]
[ 4856.602804]  ? rtrs_clt_rdma_cm_handler+0xda0/0xda0 [rtrs_client]
[ 4856.602857]  ? check_flags.part.31+0x6c/0x1f0
[ 4856.602927]  ? rcu_read_lock_sched_held+0xaf/0xe0
[ 4856.602963]  ? rcu_read_lock_bh_held+0xc0/0xc0
[ 4856.603137]  __ib_process_cq+0x10a/0x350 [ib_core]
[ 4856.603309]  ib_poll_handler+0x41/0x1c0 [ib_core]
[ 4856.603358]  irq_poll_softirq+0xe6/0x280
[ 4856.603392]  ? lockdep_hardirqs_on_prepare+0x111/0x210
[ 4856.603446]  __do_softirq+0x10d/0x646
[ 4856.603540]  asm_call_irq_on_stack+0x12/0x20
[ 4856.603563]  </IRQ>

[ 4856.605096] Allocated by task 8914:
[ 4856.605510]  kasan_save_stack+0x19/0x40
[ 4856.605532]  __kasan_kmalloc.constprop.7+0xc1/0xd0
[ 4856.605552]  __kmalloc+0x155/0x320
[ 4856.605574]  __sg_alloc_table+0x155/0x1c0
[ 4856.605594]  sg_alloc_table+0x1f/0x50
[ 4856.605620]  send_msg_sess_info+0x119/0x2e0 [rnbd_client]
[ 4856.605646]  remap_devs+0x71/0x210 [rnbd_client]
[ 4856.605676]  init_sess+0xad8/0xe10 [rtrs_client]
[ 4856.605706]  rtrs_clt_reconnect_work+0xd6/0x170 [rtrs_client]
[ 4856.605728]  process_one_work+0x521/0xa90
[ 4856.605748]  worker_thread+0x65/0x5b0
[ 4856.605769]  kthread+0x1f2/0x210
[ 4856.605789]  ret_from_fork+0x22/0x30

[ 4856.606159] Freed by task 8914:
[ 4856.606559]  kasan_save_stack+0x19/0x40
[ 4856.606580]  kasan_set_track+0x1c/0x30
[ 4856.606601]  kasan_set_free_info+0x1b/0x30
[ 4856.606622]  __kasan_slab_free+0x108/0x150
[ 4856.606642]  slab_free_freelist_hook+0x64/0x190
[ 4856.606661]  kfree+0xe2/0x650
[ 4856.606681]  __sg_free_table+0xa4/0x100
[ 4856.606707]  send_msg_sess_info+0x1d6/0x2e0 [rnbd_client]
[ 4856.606733]  remap_devs+0x71/0x210 [rnbd_client]
[ 4856.606763]  init_sess+0xad8/0xe10 [rtrs_client]
[ 4856.606792]  rtrs_clt_reconnect_work+0xd6/0x170 [rtrs_client]
[ 4856.606813]  process_one_work+0x521/0xa90
[ 4856.606833]  worker_thread+0x65/0x5b0
[ 4856.606853]  kthread+0x1f2/0x210
[ 4856.606872]  ret_from_fork+0x22/0x30

The solution is to free iu's sgtable after the iu is not used anymore.
And also move sg_alloc_table into rnbd_get_iu accordingly.

Fixes: 5a1328d ("block/rnbd-clt: Dynamically allocate sglist for rnbd_iu")
Signed-off-by: Guoqing Jiang <[email protected]>
Signed-off-by: Jack Wang <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
commodo pushed a commit that referenced this pull request Feb 19, 2021
We had kernel panic, it is caused by unload module and last
close confirmation.

call trace:
[1196029.743127]  free_sess+0x15/0x50 [rtrs_client]
[1196029.743128]  rtrs_clt_close+0x4c/0x70 [rtrs_client]
[1196029.743129]  ? rnbd_clt_unmap_device+0x1b0/0x1b0 [rnbd_client]
[1196029.743130]  close_rtrs+0x25/0x50 [rnbd_client]
[1196029.743131]  rnbd_client_exit+0x93/0xb99 [rnbd_client]
[1196029.743132]  __x64_sys_delete_module+0x190/0x260

And in the crashdump confirmation kworker is also running.
PID: 6943   TASK: ffff9e2ac8098000  CPU: 4   COMMAND: "kworker/4:2"
 #0 [ffffb206cf337c30] __schedule at ffffffff9f93f891
 #1 [ffffb206cf337cc8] schedule at ffffffff9f93fe98
 #2 [ffffb206cf337cd0] schedule_timeout at ffffffff9f943938
 #3 [ffffb206cf337d50] wait_for_completion at ffffffff9f9410a7
 #4 [ffffb206cf337da0] __flush_work at ffffffff9f08ce0e
 #5 [ffffb206cf337e20] rtrs_clt_close_conns at ffffffffc0d5f668 [rtrs_client]
 #6 [ffffb206cf337e48] rtrs_clt_close at ffffffffc0d5f801 [rtrs_client]
 #7 [ffffb206cf337e68] close_rtrs at ffffffffc0d26255 [rnbd_client]
 #8 [ffffb206cf337e78] free_sess at ffffffffc0d262ad [rnbd_client]
 #9 [ffffb206cf337e88] rnbd_clt_put_dev at ffffffffc0d266a7 [rnbd_client]

The problem is both code path try to close same session, which lead to
panic.

To fix it, just skip the sess if the refcount already drop to 0.

Fixes: f7a7a5c ("block/rnbd: client: main functionality")
Signed-off-by: Jack Wang <[email protected]>
Reviewed-by: Gioh Kim <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
nunojsa pushed a commit that referenced this pull request Mar 13, 2023
The Xen interrupt injection for event channels relies on accessing the
guest's vcpu_info structure in __kvm_xen_has_interrupt(), through a
gfn_to_hva_cache.

This requires the srcu lock to be held, which is mostly the case except
for this code path:

[   11.822877] WARNING: suspicious RCU usage
[   11.822965] -----------------------------
[   11.823013] include/linux/kvm_host.h:664 suspicious rcu_dereference_check() usage!
[   11.823131]
[   11.823131] other info that might help us debug this:
[   11.823131]
[   11.823196]
[   11.823196] rcu_scheduler_active = 2, debug_locks = 1
[   11.823253] 1 lock held by dom:0/90:
[   11.823292]  #0: ffff998956ec8118 (&vcpu->mutex){+.+.}, at: kvm_vcpu_ioctl+0x85/0x680
[   11.823379]
[   11.823379] stack backtrace:
[   11.823428] CPU: 2 PID: 90 Comm: dom:0 Kdump: loaded Not tainted 5.4.34+ #5
[   11.823496] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
[   11.823612] Call Trace:
[   11.823645]  dump_stack+0x7a/0xa5
[   11.823681]  lockdep_rcu_suspicious+0xc5/0x100
[   11.823726]  __kvm_xen_has_interrupt+0x179/0x190
[   11.823773]  kvm_cpu_has_extint+0x6d/0x90
[   11.823813]  kvm_cpu_accept_dm_intr+0xd/0x40
[   11.823853]  kvm_vcpu_ready_for_interrupt_injection+0x20/0x30
              < post_kvm_run_save() inlined here >
[   11.823906]  kvm_arch_vcpu_ioctl_run+0x135/0x6a0
[   11.823947]  kvm_vcpu_ioctl+0x263/0x680

Fixes: 40da8cc ("KVM: x86/xen: Add event channel interrupt vector upcall")
Signed-off-by: David Woodhouse <[email protected]>
Cc: [email protected]
Message-Id: <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
btogorean pushed a commit that referenced this pull request Aug 25, 2023
[ Upstream commit 93c660c ]

ASAN reports an use-after-free in btf_dump_name_dups:

ERROR: AddressSanitizer: heap-use-after-free on address 0xffff927006db at pc 0xaaaab5dfb618 bp 0xffffdd89b890 sp 0xffffdd89b928
READ of size 2 at 0xffff927006db thread T0
    #0 0xaaaab5dfb614 in __interceptor_strcmp.part.0 (test_progs+0x21b614)
    #1 0xaaaab635f144 in str_equal_fn tools/lib/bpf/btf_dump.c:127
    #2 0xaaaab635e3e0 in hashmap_find_entry tools/lib/bpf/hashmap.c:143
    #3 0xaaaab635e72c in hashmap__find tools/lib/bpf/hashmap.c:212
    #4 0xaaaab6362258 in btf_dump_name_dups tools/lib/bpf/btf_dump.c:1525
    #5 0xaaaab636240c in btf_dump_resolve_name tools/lib/bpf/btf_dump.c:1552
    #6 0xaaaab6362598 in btf_dump_type_name tools/lib/bpf/btf_dump.c:1567
    #7 0xaaaab6360b48 in btf_dump_emit_struct_def tools/lib/bpf/btf_dump.c:912
    #8 0xaaaab6360630 in btf_dump_emit_type tools/lib/bpf/btf_dump.c:798
    #9 0xaaaab635f720 in btf_dump__dump_type tools/lib/bpf/btf_dump.c:282
    #10 0xaaaab608523c in test_btf_dump_incremental tools/testing/selftests/bpf/prog_tests/btf_dump.c:236
    #11 0xaaaab6097530 in test_btf_dump tools/testing/selftests/bpf/prog_tests/btf_dump.c:875
    #12 0xaaaab6314ed0 in run_one_test tools/testing/selftests/bpf/test_progs.c:1062
    #13 0xaaaab631a0a8 in main tools/testing/selftests/bpf/test_progs.c:1697
    #14 0xffff9676d214 in __libc_start_main ../csu/libc-start.c:308
    #15 0xaaaab5d65990  (test_progs+0x185990)

0xffff927006db is located 11 bytes inside of 16-byte region [0xffff927006d0,0xffff927006e0)
freed by thread T0 here:
    #0 0xaaaab5e2c7c4 in realloc (test_progs+0x24c7c4)
    #1 0xaaaab634f4a0 in libbpf_reallocarray tools/lib/bpf/libbpf_internal.h:191
    #2 0xaaaab634f840 in libbpf_add_mem tools/lib/bpf/btf.c:163
    #3 0xaaaab636643c in strset_add_str_mem tools/lib/bpf/strset.c:106
    #4 0xaaaab6366560 in strset__add_str tools/lib/bpf/strset.c:157
    #5 0xaaaab6352d70 in btf__add_str tools/lib/bpf/btf.c:1519
    #6 0xaaaab6353e10 in btf__add_field tools/lib/bpf/btf.c:2032
    #7 0xaaaab6084fcc in test_btf_dump_incremental tools/testing/selftests/bpf/prog_tests/btf_dump.c:232
    #8 0xaaaab6097530 in test_btf_dump tools/testing/selftests/bpf/prog_tests/btf_dump.c:875
    #9 0xaaaab6314ed0 in run_one_test tools/testing/selftests/bpf/test_progs.c:1062
    #10 0xaaaab631a0a8 in main tools/testing/selftests/bpf/test_progs.c:1697
    #11 0xffff9676d214 in __libc_start_main ../csu/libc-start.c:308
    #12 0xaaaab5d65990  (test_progs+0x185990)

previously allocated by thread T0 here:
    #0 0xaaaab5e2c7c4 in realloc (test_progs+0x24c7c4)
    #1 0xaaaab634f4a0 in libbpf_reallocarray tools/lib/bpf/libbpf_internal.h:191
    #2 0xaaaab634f840 in libbpf_add_mem tools/lib/bpf/btf.c:163
    #3 0xaaaab636643c in strset_add_str_mem tools/lib/bpf/strset.c:106
    #4 0xaaaab6366560 in strset__add_str tools/lib/bpf/strset.c:157
    #5 0xaaaab6352d70 in btf__add_str tools/lib/bpf/btf.c:1519
    #6 0xaaaab6353ff0 in btf_add_enum_common tools/lib/bpf/btf.c:2070
    #7 0xaaaab6354080 in btf__add_enum tools/lib/bpf/btf.c:2102
    #8 0xaaaab6082f50 in test_btf_dump_incremental tools/testing/selftests/bpf/prog_tests/btf_dump.c:162
    #9 0xaaaab6097530 in test_btf_dump tools/testing/selftests/bpf/prog_tests/btf_dump.c:875
    #10 0xaaaab6314ed0 in run_one_test tools/testing/selftests/bpf/test_progs.c:1062
    #11 0xaaaab631a0a8 in main tools/testing/selftests/bpf/test_progs.c:1697
    #12 0xffff9676d214 in __libc_start_main ../csu/libc-start.c:308
    #13 0xaaaab5d65990  (test_progs+0x185990)

The reason is that the key stored in hash table name_map is a string
address, and the string memory is allocated by realloc() function, when
the memory is resized by realloc() later, the old memory may be freed,
so the address stored in name_map references to a freed memory, causing
use-after-free.

Fix it by storing duplicated string address in name_map.

Fixes: 919d2b1 ("libbpf: Allow modification of BTF and add btf__add_str API")
Signed-off-by: Xu Kuohai <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Acked-by: Martin KaFai Lau <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
btogorean pushed a commit that referenced this pull request Aug 25, 2023
[ Upstream commit 0473cba ]

We see kernel crashes and lockups and KASAN errors related to ax210
firmware crashes.  One of the KASAN dumps pointed at the tx path,
and it appears there is indeed a way to double-free an skb.

If iwl_mvm_tx_skb_sta returns non-zero, then the 'skb' sent into the
method will be freed.  But, in case where we build TSO skb buffer,
the skb may also be freed in error case.  So, return 0 in that particular
error case and do cleanup manually.

BUG: KASAN: use-after-free in __list_del_entry_valid+0x12/0x90
iwlwifi 0000:06:00.0: 0x00000000 | tsf hi
Read of size 8 at addr ffff88813cfa4ba0 by task btserver/9650

CPU: 4 PID: 9650 Comm: btserver Tainted: G        W         5.19.8+ #5
iwlwifi 0000:06:00.0: 0x00000000 | time gp1
Hardware name: Default string Default string/SKYBAY, BIOS 5.12 02/19/2019
Call Trace:
 <TASK>
 dump_stack_lvl+0x55/0x6d
 print_report.cold.12+0xf2/0x684
iwlwifi 0000:06:00.0: 0x1D0915A8 | time gp2
 ? __list_del_entry_valid+0x12/0x90
 kasan_report+0x8b/0x180
iwlwifi 0000:06:00.0: 0x00000001 | uCode revision type
 ? __list_del_entry_valid+0x12/0x90
 __list_del_entry_valid+0x12/0x90
iwlwifi 0000:06:00.0: 0x00000048 | uCode version major
 tcp_update_skb_after_send+0x5d/0x170
 __tcp_transmit_skb+0xb61/0x15c0
iwlwifi 0000:06:00.0: 0xDAA05125 | uCode version minor
 ? __tcp_select_window+0x490/0x490
iwlwifi 0000:06:00.0: 0x00000420 | hw version
 ? trace_kmalloc_node+0x29/0xd0
 ? __kmalloc_node_track_caller+0x12a/0x260
 ? memset+0x1f/0x40
 ? __build_skb_around+0x125/0x150
 ? __alloc_skb+0x1d4/0x220
 ? skb_zerocopy_clone+0x55/0x230
iwlwifi 0000:06:00.0: 0x00489002 | board version
 ? kmalloc_reserve+0x80/0x80
 ? rcu_read_lock_bh_held+0x60/0xb0
 tcp_write_xmit+0x3f1/0x24d0
iwlwifi 0000:06:00.0: 0x034E001C | hcmd
 ? __check_object_size+0x180/0x350
iwlwifi 0000:06:00.0: 0x24020000 | isr0
 tcp_sendmsg_locked+0x8a9/0x1520
iwlwifi 0000:06:00.0: 0x01400000 | isr1
 ? tcp_sendpage+0x50/0x50
iwlwifi 0000:06:00.0: 0x48F0000A | isr2
 ? lock_release+0xb9/0x400
 ? tcp_sendmsg+0x14/0x40
iwlwifi 0000:06:00.0: 0x00C3080C | isr3
 ? lock_downgrade+0x390/0x390
 ? do_raw_spin_lock+0x114/0x1d0
iwlwifi 0000:06:00.0: 0x00200000 | isr4
 ? rwlock_bug.part.2+0x50/0x50
iwlwifi 0000:06:00.0: 0x034A001C | last cmd Id
 ? rwlock_bug.part.2+0x50/0x50
 ? lockdep_hardirqs_on_prepare+0xe/0x200
iwlwifi 0000:06:00.0: 0x0000C2F0 | wait_event
 ? __local_bh_enable_ip+0x87/0xe0
 ? inet_send_prepare+0x220/0x220
iwlwifi 0000:06:00.0: 0x000000C4 | l2p_control
 tcp_sendmsg+0x22/0x40
 sock_sendmsg+0x5f/0x70
iwlwifi 0000:06:00.0: 0x00010034 | l2p_duration
 __sys_sendto+0x19d/0x250
iwlwifi 0000:06:00.0: 0x00000007 | l2p_mhvalid
 ? __ia32_sys_getpeername+0x40/0x40
iwlwifi 0000:06:00.0: 0x00000000 | l2p_addr_match
 ? rcu_read_lock_held_common+0x12/0x50
 ? rcu_read_lock_sched_held+0x5a/0xd0
 ? rcu_read_lock_bh_held+0xb0/0xb0
 ? rcu_read_lock_sched_held+0x5a/0xd0
 ? rcu_read_lock_sched_held+0x5a/0xd0
 ? lock_release+0xb9/0x400
 ? lock_downgrade+0x390/0x390
 ? ktime_get+0x64/0x130
 ? ktime_get+0x8d/0x130
 ? rcu_read_lock_held_common+0x12/0x50
 ? rcu_read_lock_sched_held+0x5a/0xd0
 ? rcu_read_lock_held_common+0x12/0x50
 ? rcu_read_lock_sched_held+0x5a/0xd0
 ? rcu_read_lock_bh_held+0xb0/0xb0
 ? rcu_read_lock_bh_held+0xb0/0xb0
 __x64_sys_sendto+0x6f/0x80
 do_syscall_64+0x34/0xb0
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f1d126e4531
Code: 00 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 48 8d 05 35 80 0c 00 41 89 ca 8b 00 85 c0 75 1c 45 31 c9 45 31 c0 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 67 c3 66 0f 1f 44 00 00 55 48 83 ec 20 48 89
RSP: 002b:00007ffe21a679d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000000000000ffdc RCX: 00007f1d126e4531
RDX: 0000000000010000 RSI: 000000000374acf0 RDI: 0000000000000014
RBP: 00007ffe21a67ac0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000010
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000
 </TASK>

Allocated by task 9650:
 kasan_save_stack+0x1c/0x40
 __kasan_slab_alloc+0x6d/0x90
 kmem_cache_alloc_node+0xf3/0x2b0
 __alloc_skb+0x191/0x220
 tcp_stream_alloc_skb+0x3f/0x330
 tcp_sendmsg_locked+0x67c/0x1520
 tcp_sendmsg+0x22/0x40
 sock_sendmsg+0x5f/0x70
 __sys_sendto+0x19d/0x250
 __x64_sys_sendto+0x6f/0x80
 do_syscall_64+0x34/0xb0
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

Freed by task 9650:
 kasan_save_stack+0x1c/0x40
 kasan_set_track+0x21/0x30
 kasan_set_free_info+0x20/0x30
 __kasan_slab_free+0x102/0x170
 kmem_cache_free+0xc8/0x3e0
 iwl_mvm_mac_itxq_xmit+0x124/0x270 [iwlmvm]
 ieee80211_queue_skb+0x874/0xd10 [mac80211]
 ieee80211_xmit_fast+0xf80/0x1180 [mac80211]
 __ieee80211_subif_start_xmit+0x287/0x680 [mac80211]
 ieee80211_subif_start_xmit+0xcd/0x730 [mac80211]
 dev_hard_start_xmit+0xf6/0x420
 __dev_queue_xmit+0x165b/0x1b50
 ip_finish_output2+0x66e/0xfb0
 __ip_finish_output+0x487/0x6d0
 ip_output+0x11c/0x350
 __ip_queue_xmit+0x36b/0x9d0
 __tcp_transmit_skb+0xb35/0x15c0
 tcp_write_xmit+0x3f1/0x24d0
 tcp_sendmsg_locked+0x8a9/0x1520
 tcp_sendmsg+0x22/0x40
 sock_sendmsg+0x5f/0x70
 __sys_sendto+0x19d/0x250
 __x64_sys_sendto+0x6f/0x80
 do_syscall_64+0x34/0xb0
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

The buggy address belongs to the object at ffff88813cfa4b40
 which belongs to the cache skbuff_fclone_cache of size 472
The buggy address is located 96 bytes inside of
 472-byte region [ffff88813cfa4b40, ffff88813cfa4d18)

The buggy address belongs to the physical page:
page:ffffea0004f3e900 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88813cfa6c40 pfn:0x13cfa4
head:ffffea0004f3e900 order:2 compound_mapcount:0 compound_pincount:0
flags: 0x5fff8000010200(slab|head|node=0|zone=2|lastcpupid=0x3fff)
raw: 005fff8000010200 ffffea0004656b08 ffffea0008e8cf08 ffff8881081a5240
raw: ffff88813cfa6c40 0000000000170015 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88813cfa4a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88813cfa4b00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
>ffff88813cfa4b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff88813cfa4c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88813cfa4c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Fixes: 08f7d8b ("iwlwifi: mvm: bring back mvm GSO code")
Link: https://lore.kernel.org/linux-wireless/[email protected]/
Tested-by: Amol Jawale <[email protected]>
Signed-off-by: Ben Greear <[email protected]>
Link: https://lore.kernel.org/r/20221123225313.21b1ee31d666.I3b3ba184433dd2a544d91eeeda29b467021824ae@changeid
Signed-off-by: Gregory Greenman <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
btogorean pushed a commit that referenced this pull request Aug 25, 2023
…g the sock

[ Upstream commit 3cf7203 ]

There is a race condition in vxlan that when deleting a vxlan device
during receiving packets, there is a possibility that the sock is
released after getting vxlan_sock vs from sk_user_data. Then in
later vxlan_ecn_decapsulate(), vxlan_get_sk_family() we will got
NULL pointer dereference. e.g.

   #0 [ffffa25ec6978a38] machine_kexec at ffffffff8c669757
   #1 [ffffa25ec6978a90] __crash_kexec at ffffffff8c7c0a4d
   #2 [ffffa25ec6978b58] crash_kexec at ffffffff8c7c1c48
   #3 [ffffa25ec6978b60] oops_end at ffffffff8c627f2b
   #4 [ffffa25ec6978b80] page_fault_oops at ffffffff8c678fcb
   #5 [ffffa25ec6978bd8] exc_page_fault at ffffffff8d109542
   #6 [ffffa25ec6978c00] asm_exc_page_fault at ffffffff8d200b62
      [exception RIP: vxlan_ecn_decapsulate+0x3b]
      RIP: ffffffffc1014e7b  RSP: ffffa25ec6978cb0  RFLAGS: 00010246
      RAX: 0000000000000008  RBX: ffff8aa000888000  RCX: 0000000000000000
      RDX: 000000000000000e  RSI: ffff8a9fc7ab803e  RDI: ffff8a9fd1168700
      RBP: ffff8a9fc7ab803e   R8: 0000000000700000   R9: 00000000000010ae
      R10: ffff8a9fcb748980  R11: 0000000000000000  R12: ffff8a9fd1168700
      R13: ffff8aa000888000  R14: 00000000002a0000  R15: 00000000000010ae
      ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
   #7 [ffffa25ec6978ce8] vxlan_rcv at ffffffffc10189cd [vxlan]
   #8 [ffffa25ec6978d90] udp_queue_rcv_one_skb at ffffffff8cfb6507
   #9 [ffffa25ec6978dc0] udp_unicast_rcv_skb at ffffffff8cfb6e45
  #10 [ffffa25ec6978dc8] __udp4_lib_rcv at ffffffff8cfb8807
  #11 [ffffa25ec6978e20] ip_protocol_deliver_rcu at ffffffff8cf76951
  #12 [ffffa25ec6978e48] ip_local_deliver at ffffffff8cf76bde
  #13 [ffffa25ec6978ea0] __netif_receive_skb_one_core at ffffffff8cecde9b
  #14 [ffffa25ec6978ec8] process_backlog at ffffffff8cece139
  #15 [ffffa25ec6978f00] __napi_poll at ffffffff8ceced1a
  #16 [ffffa25ec6978f28] net_rx_action at ffffffff8cecf1f3
  #17 [ffffa25ec6978fa0] __softirqentry_text_start at ffffffff8d4000ca
  #18 [ffffa25ec6978ff0] do_softirq at ffffffff8c6fbdc3

Reproducer: https://github.com/Mellanox/ovs-tests/blob/master/test-ovs-vxlan-remove-tunnel-during-traffic.sh

Fix this by waiting for all sk_user_data reader to finish before
releasing the sock.

Reported-by: Jianlin Shi <[email protected]>
Suggested-by: Jakub Sitnicki <[email protected]>
Fixes: 6a93cc9 ("udp-tunnel: Add a few more UDP tunnel APIs")
Signed-off-by: Hangbin Liu <[email protected]>
Reviewed-by: Jiri Pirko <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
btogorean pushed a commit that referenced this pull request Aug 25, 2023
[ Upstream commit 0b66046 ]

When the NTFS BOOT record_size field < 0, it represents a
shift value. However, there is no sanity check on the shift result
and the sbi->record_bits calculation through blksize_bits() assumes
the size always > 256, which could lead to NPD while mounting a
malformed NTFS image.

[  318.675159] BUG: kernel NULL pointer dereference, address: 0000000000000158
[  318.675682] #PF: supervisor read access in kernel mode
[  318.675869] #PF: error_code(0x0000) - not-present page
[  318.676246] PGD 0 P4D 0
[  318.676502] Oops: 0000 [#1] PREEMPT SMP NOPTI
[  318.676934] CPU: 0 PID: 259 Comm: mount Not tainted 5.19.0 #5
[  318.677289] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[  318.678136] RIP: 0010:ni_find_attr+0x2d/0x1c0
[  318.678656] Code: 89 ca 4d 89 c7 41 56 41 55 41 54 41 89 cc 55 48 89 fd 53 48 89 d3 48 83 ec 20 65 48 8b 04 25 28 00 00 00 48 89 44 24 180
[  318.679848] RSP: 0018:ffffa6c8c0297bd8 EFLAGS: 00000246
[  318.680104] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000080
[  318.680790] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[  318.681679] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[  318.682577] R10: 0000000000000000 R11: 0000000000000005 R12: 0000000000000080
[  318.683015] R13: ffff8d5582e68400 R14: 0000000000000100 R15: 0000000000000000
[  318.683618] FS:  00007fd9e1c81e40(0000) GS:ffff8d55fdc00000(0000) knlGS:0000000000000000
[  318.684280] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  318.684651] CR2: 0000000000000158 CR3: 0000000002e1a000 CR4: 00000000000006f0
[  318.685623] Call Trace:
[  318.686607]  <TASK>
[  318.686872]  ? ntfs_alloc_inode+0x1a/0x60
[  318.687235]  attr_load_runs_vcn+0x2b/0xa0
[  318.687468]  mi_read+0xbb/0x250
[  318.687576]  ntfs_iget5+0x114/0xd90
[  318.687750]  ntfs_fill_super+0x588/0x11b0
[  318.687953]  ? put_ntfs+0x130/0x130
[  318.688065]  ? snprintf+0x49/0x70
[  318.688164]  ? put_ntfs+0x130/0x130
[  318.688256]  get_tree_bdev+0x16a/0x260
[  318.688407]  vfs_get_tree+0x20/0xb0
[  318.688519]  path_mount+0x2dc/0x9b0
[  318.688877]  do_mount+0x74/0x90
[  318.689142]  __x64_sys_mount+0x89/0xd0
[  318.689636]  do_syscall_64+0x3b/0x90
[  318.689998]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
[  318.690318] RIP: 0033:0x7fd9e133c48a
[  318.690687] Code: 48 8b 0d 11 fa 2a 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 008
[  318.691357] RSP: 002b:00007ffd374406c8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
[  318.691632] RAX: ffffffffffffffda RBX: 0000564d0b051080 RCX: 00007fd9e133c48a
[  318.691920] RDX: 0000564d0b051280 RSI: 0000564d0b051300 RDI: 0000564d0b0596a0
[  318.692123] RBP: 0000000000000000 R08: 0000564d0b0512a0 R09: 0000000000000020
[  318.692349] R10: 00000000c0ed0000 R11: 0000000000000202 R12: 0000564d0b0596a0
[  318.692673] R13: 0000564d0b051280 R14: 0000000000000000 R15: 00000000ffffffff
[  318.693007]  </TASK>
[  318.693271] Modules linked in:
[  318.693614] CR2: 0000000000000158
[  318.694446] ---[ end trace 0000000000000000 ]---
[  318.694779] RIP: 0010:ni_find_attr+0x2d/0x1c0
[  318.694952] Code: 89 ca 4d 89 c7 41 56 41 55 41 54 41 89 cc 55 48 89 fd 53 48 89 d3 48 83 ec 20 65 48 8b 04 25 28 00 00 00 48 89 44 24 180
[  318.696042] RSP: 0018:ffffa6c8c0297bd8 EFLAGS: 00000246
[  318.696531] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000080
[  318.698114] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[  318.699286] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[  318.699795] R10: 0000000000000000 R11: 0000000000000005 R12: 0000000000000080
[  318.700236] R13: ffff8d5582e68400 R14: 0000000000000100 R15: 0000000000000000
[  318.700973] FS:  00007fd9e1c81e40(0000) GS:ffff8d55fdc00000(0000) knlGS:0000000000000000
[  318.701688] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  318.702190] CR2: 0000000000000158 CR3: 0000000002e1a000 CR4: 00000000000006f0
[  318.726510] mount (259) used greatest stack depth: 13320 bytes left

This patch adds a sanity check.

Signed-off-by: edward lo <[email protected]>
Signed-off-by: Konstantin Komarov <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 9, 2025
…ockup

Since we use 16-bit precision, the raw data will undergo integer division,
which may sometimes result in data loss.  This can lead to slightly
inaccurate CPU utilization calculations.  Under normal circumstances, this
isn't an issue.  However, when CPU utilization reaches 100%, the
calculated result might exceed 100%.  For example, with raw data like the
following:

sample_period 400000134 new_stat 83648414036 old_stat 83247417494

sample_period=400000134/2^24=23
new_stat=83648414036/2^24=4985
old_stat=83247417494/2^24=4961
util=105%

Below log will output:

CPU#3 Utilization every 0s during lockup:
    #1:   0% system,          0% softirq,   105% hardirq,     0% idle
    #2:   0% system,          0% softirq,   105% hardirq,     0% idle
    #3:   0% system,          0% softirq,   100% hardirq,     0% idle
    #4:   0% system,          0% softirq,   105% hardirq,     0% idle
    #5:   0% system,          0% softirq,   105% hardirq,     0% idle

To avoid confusion, we enforce a 100% display cap when calculations exceed
this threshold.

We also round to the nearest multiple of 16.8 milliseconds to improve the
accuracy.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: ZhenguoYao <[email protected]>
Cc: Bitao Hu <[email protected]>
Cc: Li Huafei <[email protected]>
Cc: Max Kellermann <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 11, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 11, 2025
…ockup

Since we use 16-bit precision, the raw data will undergo integer division,
which may sometimes result in data loss.  This can lead to slightly
inaccurate CPU utilization calculations.  Under normal circumstances, this
isn't an issue.  However, when CPU utilization reaches 100%, the
calculated result might exceed 100%.  For example, with raw data like the
following:

sample_period 400000134 new_stat 83648414036 old_stat 83247417494

sample_period=400000134/2^24=23
new_stat=83648414036/2^24=4985
old_stat=83247417494/2^24=4961
util=105%

Below log will output:

CPU#3 Utilization every 0s during lockup:
    #1:   0% system,          0% softirq,   105% hardirq,     0% idle
    #2:   0% system,          0% softirq,   105% hardirq,     0% idle
    #3:   0% system,          0% softirq,   100% hardirq,     0% idle
    #4:   0% system,          0% softirq,   105% hardirq,     0% idle
    #5:   0% system,          0% softirq,   105% hardirq,     0% idle

To avoid confusion, we enforce a 100% display cap when calculations exceed
this threshold.

We also round to the nearest multiple of 16.8 milliseconds to improve the
accuracy.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: ZhenguoYao <[email protected]>
Cc: Bitao Hu <[email protected]>
Cc: Li Huafei <[email protected]>
Cc: Max Kellermann <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 12, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 12, 2025
…ockup

Since we use 16-bit precision, the raw data will undergo integer division,
which may sometimes result in data loss.  This can lead to slightly
inaccurate CPU utilization calculations.  Under normal circumstances, this
isn't an issue.  However, when CPU utilization reaches 100%, the
calculated result might exceed 100%.  For example, with raw data like the
following:

sample_period 400000134 new_stat 83648414036 old_stat 83247417494

sample_period=400000134/2^24=23
new_stat=83648414036/2^24=4985
old_stat=83247417494/2^24=4961
util=105%

Below log will output:

CPU#3 Utilization every 0s during lockup:
    #1:   0% system,          0% softirq,   105% hardirq,     0% idle
    #2:   0% system,          0% softirq,   105% hardirq,     0% idle
    #3:   0% system,          0% softirq,   100% hardirq,     0% idle
    #4:   0% system,          0% softirq,   105% hardirq,     0% idle
    #5:   0% system,          0% softirq,   105% hardirq,     0% idle

To avoid confusion, we enforce a 100% display cap when calculations exceed
this threshold.

We also round to the nearest multiple of 16.8 milliseconds to improve the
accuracy.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: ZhenguoYao <[email protected]>
Cc: Bitao Hu <[email protected]>
Cc: Li Huafei <[email protected]>
Cc: Max Kellermann <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 13, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 13, 2025
…ockup

Since we use 16-bit precision, the raw data will undergo integer division,
which may sometimes result in data loss.  This can lead to slightly
inaccurate CPU utilization calculations.  Under normal circumstances, this
isn't an issue.  However, when CPU utilization reaches 100%, the
calculated result might exceed 100%.  For example, with raw data like the
following:

sample_period 400000134 new_stat 83648414036 old_stat 83247417494

sample_period=400000134/2^24=23
new_stat=83648414036/2^24=4985
old_stat=83247417494/2^24=4961
util=105%

Below log will output:

CPU#3 Utilization every 0s during lockup:
    #1:   0% system,          0% softirq,   105% hardirq,     0% idle
    #2:   0% system,          0% softirq,   105% hardirq,     0% idle
    #3:   0% system,          0% softirq,   100% hardirq,     0% idle
    #4:   0% system,          0% softirq,   105% hardirq,     0% idle
    #5:   0% system,          0% softirq,   105% hardirq,     0% idle

To avoid confusion, we enforce a 100% display cap when calculations exceed
this threshold.

We also round to the nearest multiple of 16.8 milliseconds to improve the
accuracy.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: ZhenguoYao <[email protected]>
Cc: Bitao Hu <[email protected]>
Cc: Li Huafei <[email protected]>
Cc: Max Kellermann <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 16, 2025
…lockup

Since we use 16-bit precision, the raw data will undergo integer division,
which may sometimes result in data loss.  This can lead to slightly
inaccurate CPU utilization calculations.  Under normal circumstances, this
isn't an issue.  However, when CPU utilization reaches 100%, the
calculated result might exceed 100%.  For example, with raw data like the
following:

sample_period 400000134 new_stat 83648414036 old_stat 83247417494

sample_period=400000134/2^24=23
new_stat=83648414036/2^24=4985
old_stat=83247417494/2^24=4961
util=105%

Below log will output:

CPU#3 Utilization every 0s during lockup:
    #1:   0% system,          0% softirq,   105% hardirq,     0% idle
    #2:   0% system,          0% softirq,   105% hardirq,     0% idle
    #3:   0% system,          0% softirq,   100% hardirq,     0% idle
    #4:   0% system,          0% softirq,   105% hardirq,     0% idle
    #5:   0% system,          0% softirq,   105% hardirq,     0% idle

To avoid confusion, we enforce a 100% display cap when calculations exceed
this threshold.

We also round to the nearest multiple of 16.8 milliseconds to improve the
accuracy.

[[email protected]: make get_16bit_precision() more accurate, fix comment layout]
  Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: ZhenguoYao <[email protected]>
Cc: Bitao Hu <[email protected]>
Cc: Li Huafei <[email protected]>
Cc: Max Kellermann <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 16, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 16, 2025
Petr Machata says:

====================
bridge: Allow keeping local FDB entries only on VLAN 0

The bridge FDB contains one local entry per port per VLAN, for the MAC of
the port in question, and likewise for the bridge itself. This allows
bridge to locally receive and punt "up" any packets whose destination MAC
address matches that of one of the bridge interfaces or of the bridge
itself.

The number of these local "service" FDB entries grows linearly with number
of bridge-global VLAN memberships, but that in turn will tend to grow
quadratically with number of ports and per-port VLAN memberships. While
that does not cause issues during forwarding lookups, it does make dumps
impractically slow.

As an example, with 100 interfaces, each on 4K VLANs, a full dump of FDB
that just contains these 400K local entries, takes 6.5s. That's _without_
considering iproute2 formatting overhead, this is just how long it takes to
walk the FDB (repeatedly), serialize it into netlink messages, and parse
the messages back in userspace.

This is to illustrate that with growing number of ports and VLANs, the time
required to dump this repetitive information blows up. Arguably 4K VLANs
per interface is not a very realistic configuration, but then modern
switches can instead have several hundred interfaces, and we have fielded
requests for >1K VLAN memberships per port among customers.

FDB entries are currently all kept on a single linked list, and then
dumping uses this linked list to walk all entries and dump them in order.
When the message buffer is full, the iteration is cut short, and later
restarted. Of course, to restart the iteration, it's first necessary to
walk the already-dumped front part of the list before starting dumping
again. So one possibility is to organize the FDB entries in different
structure more amenable to walk restarts.

One option is to walk directly the hash table. The advantage is that no
auxiliary structure needs to be introduced. With a rough sketch of this
approach, the above scenario gets dumped in not quite 3 s, saving over 50 %
of time. However hash table iteration requires maintaining an active cursor
that must be collected when the dump is aborted. It looks like that would
require changes in the NDO protocol to allow to run this cleanup. Moreover,
on hash table resize the iteration is simply restarted. FDB dumps are
currently not guaranteed to correspond to any one particular state: entries
can be missed, or be duplicated. But with hash table iteration we would get
that plus the much less graceful resize behavior, where swaths of FDB are
duplicated.

Another option is to maintain the FDB entries in a red-black tree. We have
a PoC of this approach on hand, and the above scenario is dumped in about
2.5 s. Still not as snappy as we'd like it, but better than the hash table.
However the savings come at the expense of a more expensive insertion, and
require locking during dumps, which blocks insertion.

The upside of these approaches is that they provide benefits whatever the
FDB contents. But it does not seem like either of these is workable.
However we intend to clean up the RB tree PoC and present it for
consideration later on in case the trade-offs are considered acceptable.

Yet another option might be to use in-kernel FDB filtering, and to filter
the local entries when dumping. Unfortunately, this does not help all that
much either, because the linked-list walk still needs to happen. Also, with
the obvious filtering interface built around ndm_flags / ndm_state
filtering, one can't just exclude pure local entries in one query. One
needs to dump all non-local entries first, and then to get permanent
entries in another run filter local & added_by_user. I.e. one needs to pay
the iteration overhead twice, and then integrate the result in userspace.
To get significant savings, one would need a very specific knob like "dump,
but skip/only include local entries". But if we are adding a local-specific
knobs, maybe let's have an option to just not duplicate them in the first
place.

All this FDB duplication is there merely to make things snappy during
forwarding. But high-radix switches with thousands of VLANs typically do
not process much traffic in the SW datapath at all, but rather offload vast
majority of it. So we could exchange some of the runtime performance for a
neater FDB.

To that end, in this patchset, introduce a new bridge option,
BR_BOOLOPT_FDB_LOCAL_VLAN_0, which when enabled, has local FDB entries
installed only on VLAN 0, instead of duplicating them across all VLANs.
Then to maintain the local termination behavior, on FDB miss, the bridge
does a second lookup on VLAN 0.

Enabling this option changes the bridge behavior in expected ways. Since
the entries are only kept on VLAN 0, FDB get, flush and dump will not
perceive them on non-0 VLANs. And deleting the VLAN 0 entry affects
forwarding on all VLANs.

This patchset is loosely based on a privately circulated patch by Nikolay
Aleksandrov.

The patchset progresses as follows:

- Patch #1 introduces a bridge option to enable the above feature. Then
  patches #2 to #5 gradually patch the bridge to do the right thing when
  the option is enabled. Finally patch #6 adds the UAPI knob and the code
  for when the feature is enabled or disabled.
- Patches #7, #8 and #9 contain fixes and improvements to selftest
  libraries
- Patch #10 contains a new selftest
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 17, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 18, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
dlech pushed a commit that referenced this pull request Sep 23, 2025
…rnal()

A crash was observed with the following output:

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 2899 Comm: syz.2.399 Not tainted 6.17.0-rc5+ #5 PREEMPT(none)
RIP: 0010:trace_kprobe_create_internal+0x3fc/0x1440 kernel/trace/trace_kprobe.c:911
Call Trace:
 <TASK>
 trace_kprobe_create_cb+0xa2/0xf0 kernel/trace/trace_kprobe.c:1089
 trace_probe_create+0xf1/0x110 kernel/trace/trace_probe.c:2246
 dyn_event_create+0x45/0x70 kernel/trace/trace_dynevent.c:128
 create_or_delete_trace_kprobe+0x5e/0xc0 kernel/trace/trace_kprobe.c:1107
 trace_parse_run_command+0x1a5/0x330 kernel/trace/trace.c:10785
 vfs_write+0x2b6/0xd00 fs/read_write.c:684
 ksys_write+0x129/0x240 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x5d/0x2d0 arch/x86/entry/syscall_64.c:94
 </TASK>

Function kmemdup() may return NULL in trace_kprobe_create_internal(), add
check for it's return value.

Link: https://lore.kernel.org/all/[email protected]/

Fixes: 33b4e38 ("tracing: kprobe-event: Allocate string buffers from heap")
Signed-off-by: Wang Liang <[email protected]>
Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
dlech pushed a commit that referenced this pull request Sep 23, 2025
Patch series "mm: remove nth_page()", v2.

As discussed recently with Linus, nth_page() is just nasty and we would
like to remove it.

To recap, the reason we currently need nth_page() within a folio is
because on some kernel configs (SPARSEMEM without SPARSEMEM_VMEMMAP), the
memmap is allocated per memory section.

While buddy allocations cannot cross memory section boundaries, hugetlb
and dax folios can.

So crossing a memory section means that "page++" could do the wrong thing.
Instead, nth_page() on these problematic configs always goes from
page->pfn, to the go from (++pfn)->page, which is rather nasty.

Likely, many people have no idea when nth_page() is required and when it
might be dropped.

We refer to such problematic PFN ranges and "non-contiguous pages".  If we
only deal with "contiguous pages", there is not need for nth_page().

Besides that "obvious" folio case, we might end up using nth_page() within
CMA allocations (again, could span memory sections), and in one corner
case (kfence) when processing memblock allocations (again, could span
memory sections).

So let's handle all that, add sanity checks, and remove nth_page().

Patch #1 -> #5   : stop making SPARSEMEM_VMEMMAP user-selectable + cleanups
Patch #6 -> #13  : disallow folios to have non-contiguous pages
Patch #14 -> #20 : remove nth_page() usage within folios
Patch #22        : disallow CMA allocations of non-contiguous pages
Patch #23 -> #33 : sanity+check + remove nth_page() usage within SG entry
Patch #34        : sanity-check + remove nth_page() usage in
                   unpin_user_page_range_dirty_lock()
Patch #35        : remove nth_page() in kfence
Patch #36        : adjust stale comment regarding nth_page
Patch #37        : mm: remove nth_page()

A lot of this is inspired from the discussion at [1] between Linus, Jason
and me, so cudos to them.


This patch (of 37):

In an ideal world, we wouldn't have to deal with SPARSEMEM without
SPARSEMEM_VMEMMAP, but in particular for 32bit SPARSEMEM_VMEMMAP is
considered too costly and consequently not supported.

However, if an architecture does support SPARSEMEM with SPARSEMEM_VMEMMAP,
let's forbid the user to disable VMEMMAP: just like we already do for
arm64, s390 and x86.

So if SPARSEMEM_VMEMMAP is supported, don't allow to use SPARSEMEM without
SPARSEMEM_VMEMMAP.

This implies that the option to not use SPARSEMEM_VMEMMAP will now be gone
for loongarch, powerpc, riscv and sparc.  All architectures only enable
SPARSEMEM_VMEMMAP with 64bit support, so there should not really be a big
downside to using the VMEMMAP (quite the contrary).

This is a preparation for not supporting

(1) folio sizes that exceed a single memory section

(2) CMA allocations of non-contiguous page ranges

in SPARSEMEM without SPARSEMEM_VMEMMAP configs, whereby we want to limit
possible impact as much as possible (e.g., gigantic hugetlb page
allocations suddenly fails).

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lore.kernel.org/all/CAHk-=wiCYfNp4AJLBORU-c7ZyRBUp66W2-Et6cdQ4REx-GyQ_A@mail.gmail.com/T/#u [1]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Zi Yan <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Acked-by: SeongJae Park <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexandru Elisei <[email protected]>
Cc: Alex Dubov <[email protected]>
Cc: Alex Willamson <[email protected]>
Cc: Bart van Assche <[email protected]>
Cc: Borislav Betkov <[email protected]>
Cc: Brendan Jackman <[email protected]>
Cc: Brett Creeley <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christoph Lameter (Ampere) <[email protected]>
Cc: Damien Le Maol <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Doug Gilbert <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Inki Dae <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Jason A. Donenfeld <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Jesper Nilsson <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jonas Lahtinen <[email protected]>
Cc: Kevin Tian <[email protected]>
Cc: Lars Persson <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Maxim Levitky <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Niklas Cassel <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pavel Begunkov <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Robin Murohy <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Shameerali Kolothum Thodi <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleinxer <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yishai Hadas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Sep 30, 2025
Before disabling SR-IOV via config space accesses to the parent PF,
sriov_disable() first removes the PCI devices representing the VFs.

Since commit 9d16947 ("PCI: Add global pci_lock_rescan_remove()")
such removal operations are serialized against concurrent remove and
rescan using the pci_rescan_remove_lock. No such locking was ever added
in sriov_disable() however. In particular when commit 18f9e9d
("PCI/IOV: Factor out sriov_add_vfs()") factored out the PCI device
removal into sriov_del_vfs() there was still no locking around the
pci_iov_remove_virtfn() calls.

On s390 the lack of serialization in sriov_disable() may cause double
remove and list corruption with the below (amended) trace being observed:

  PSW:  0704c00180000000 0000000c914e4b38 (klist_put+56)
  GPRS: 000003800313fb48 0000000000000000 0000000100000001 0000000000000001
	00000000f9b520a8 0000000000000000 0000000000002fbd 00000000f4cc9480
	0000000000000001 0000000000000000 0000000000000000 0000000180692828
	00000000818e8000 000003800313fe2c 000003800313fb20 000003800313fad8
  #0 [3800313fb20] device_del at c9158ad5c
  #1 [3800313fb88] pci_remove_bus_device at c915105ba
  #2 [3800313fbd0] pci_iov_remove_virtfn at c9152f198
  #3 [3800313fc28] zpci_iov_remove_virtfn at c90fb67c0
  #4 [3800313fc60] zpci_bus_remove_device at c90fb6104
  #5 [3800313fca0] __zpci_event_availability at c90fb3dca
  #6 [3800313fd08] chsc_process_sei_nt0 at c918fe4a2
  #7 [3800313fd60] crw_collect_info at c91905822
  #8 [3800313fe10] kthread at c90feb390
  #9 [3800313fe68] __ret_from_fork at c90f6aa64
  #10 [3800313fe98] ret_from_fork at c9194f3f2.

This is because in addition to sriov_disable() removing the VFs, the
platform also generates hot-unplug events for the VFs. This being the
reverse operation to the hotplug events generated by sriov_enable() and
handled via pdev->no_vf_scan. And while the event processing takes
pci_rescan_remove_lock and checks whether the struct pci_dev still exists,
the lack of synchronization makes this checking racy.

Other races may also be possible of course though given that this lack of
locking persisted so long observable races seem very rare. Even on s390 the
list corruption was only observed with certain devices since the platform
events are only triggered by config accesses after the removal, so as long
as the removal finished synchronously they would not race. Either way the
locking is missing so fix this by adding it to the sriov_del_vfs() helper.

Just like PCI rescan-remove, locking is also missing in sriov_add_vfs()
including for the error case where pci_stop_and_remove_bus_device() is
called without the PCI rescan-remove lock being held. Even in the non-error
case, adding new PCI devices and buses should be serialized via the PCI
rescan-remove lock. Add the necessary locking.

Fixes: 18f9e9d ("PCI/IOV: Factor out sriov_add_vfs()")
Signed-off-by: Niklas Schnelle <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Benjamin Block <[email protected]>
Reviewed-by: Farhan Ali <[email protected]>
Reviewed-by: Julian Ruess <[email protected]>
Cc: [email protected]
Link: https://patch.msgid.link/[email protected]
github-actions bot pushed a commit that referenced this pull request Oct 10, 2025
The syzbot reported issue in __hfsplus_ext_cache_extent():

[   70.194323][ T9350] BUG: KMSAN: uninit-value in __hfsplus_ext_cache_extent+0x7d0/0x990
[   70.195022][ T9350]  __hfsplus_ext_cache_extent+0x7d0/0x990
[   70.195530][ T9350]  hfsplus_file_extend+0x74f/0x1cf0
[   70.195998][ T9350]  hfsplus_get_block+0xe16/0x17b0
[   70.196458][ T9350]  __block_write_begin_int+0x962/0x2ce0
[   70.196959][ T9350]  cont_write_begin+0x1000/0x1950
[   70.197416][ T9350]  hfsplus_write_begin+0x85/0x130
[   70.197873][ T9350]  generic_perform_write+0x3e8/0x1060
[   70.198374][ T9350]  __generic_file_write_iter+0x215/0x460
[   70.198892][ T9350]  generic_file_write_iter+0x109/0x5e0
[   70.199393][ T9350]  vfs_write+0xb0f/0x14e0
[   70.199771][ T9350]  ksys_write+0x23e/0x490
[   70.200149][ T9350]  __x64_sys_write+0x97/0xf0
[   70.200570][ T9350]  x64_sys_call+0x3015/0x3cf0
[   70.201065][ T9350]  do_syscall_64+0xd9/0x1d0
[   70.201506][ T9350]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[   70.202054][ T9350]
[   70.202279][ T9350] Uninit was created at:
[   70.202693][ T9350]  __kmalloc_noprof+0x621/0xf80
[   70.203149][ T9350]  hfsplus_find_init+0x8d/0x1d0
[   70.203602][ T9350]  hfsplus_file_extend+0x6ca/0x1cf0
[   70.204087][ T9350]  hfsplus_get_block+0xe16/0x17b0
[   70.204561][ T9350]  __block_write_begin_int+0x962/0x2ce0
[   70.205074][ T9350]  cont_write_begin+0x1000/0x1950
[   70.205547][ T9350]  hfsplus_write_begin+0x85/0x130
[   70.206017][ T9350]  generic_perform_write+0x3e8/0x1060
[   70.206519][ T9350]  __generic_file_write_iter+0x215/0x460
[   70.207042][ T9350]  generic_file_write_iter+0x109/0x5e0
[   70.207552][ T9350]  vfs_write+0xb0f/0x14e0
[   70.207961][ T9350]  ksys_write+0x23e/0x490
[   70.208375][ T9350]  __x64_sys_write+0x97/0xf0
[   70.208810][ T9350]  x64_sys_call+0x3015/0x3cf0
[   70.209255][ T9350]  do_syscall_64+0xd9/0x1d0
[   70.209680][ T9350]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[   70.210230][ T9350]
[   70.210454][ T9350] CPU: 2 UID: 0 PID: 9350 Comm: repro Not tainted 6.12.0-rc5 #5
[   70.211174][ T9350] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   70.212115][ T9350] =====================================================
[   70.212734][ T9350] Disabling lock debugging due to kernel taint
[   70.213284][ T9350] Kernel panic - not syncing: kmsan.panic set ...
[   70.213858][ T9350] CPU: 2 UID: 0 PID: 9350 Comm: repro Tainted: G    B              6.12.0-rc5 #5
[   70.214679][ T9350] Tainted: [B]=BAD_PAGE
[   70.215057][ T9350] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   70.215999][ T9350] Call Trace:
[   70.216309][ T9350]  <TASK>
[   70.216585][ T9350]  dump_stack_lvl+0x1fd/0x2b0
[   70.217025][ T9350]  dump_stack+0x1e/0x30
[   70.217421][ T9350]  panic+0x502/0xca0
[   70.217803][ T9350]  ? kmsan_get_metadata+0x13e/0x1c0

[   70.218294][ Message fromT sy9350]  kmsan_report+0x296/slogd@syzkaller 0x2aat Aug 18 22:11:058 ...
 kernel
:[   70.213284][ T9350] Kernel panic - not syncing: kmsan.panic [   70.220179][ T9350]  ? kmsan_get_metadata+0x13e/0x1c0
set ...
[   70.221254][ T9350]  ? __msan_warning+0x96/0x120
[   70.222066][ T9350]  ? __hfsplus_ext_cache_extent+0x7d0/0x990
[   70.223023][ T9350]  ? hfsplus_file_extend+0x74f/0x1cf0
[   70.224120][ T9350]  ? hfsplus_get_block+0xe16/0x17b0
[   70.224946][ T9350]  ? __block_write_begin_int+0x962/0x2ce0
[   70.225756][ T9350]  ? cont_write_begin+0x1000/0x1950
[   70.226337][ T9350]  ? hfsplus_write_begin+0x85/0x130
[   70.226852][ T9350]  ? generic_perform_write+0x3e8/0x1060
[   70.227405][ T9350]  ? __generic_file_write_iter+0x215/0x460
[   70.227979][ T9350]  ? generic_file_write_iter+0x109/0x5e0
[   70.228540][ T9350]  ? vfs_write+0xb0f/0x14e0
[   70.228997][ T9350]  ? ksys_write+0x23e/0x490
[   70.229458][ T9350]  ? __x64_sys_write+0x97/0xf0
[   70.229939][ T9350]  ? x64_sys_call+0x3015/0x3cf0
[   70.230432][ T9350]  ? do_syscall_64+0xd9/0x1d0
[   70.230941][ T9350]  ? entry_SYSCALL_64_after_hwframe+0x77/0x7f
[   70.231926][ T9350]  ? kmsan_get_metadata+0x13e/0x1c0
[   70.232738][ T9350]  ? kmsan_internal_set_shadow_origin+0x77/0x110
[   70.233711][ T9350]  ? kmsan_get_metadata+0x13e/0x1c0
[   70.234516][ T9350]  ? kmsan_get_shadow_origin_ptr+0x4a/0xb0
[   70.235398][ T9350]  ? __msan_metadata_ptr_for_load_4+0x24/0x40
[   70.236323][ T9350]  ? hfsplus_brec_find+0x218/0x9f0
[   70.237090][ T9350]  ? __pfx_hfs_find_rec_by_key+0x10/0x10
[   70.237938][ T9350]  ? __msan_instrument_asm_store+0xbf/0xf0
[   70.238827][ T9350]  ? __msan_metadata_ptr_for_store_4+0x27/0x40
[   70.239772][ T9350]  ? __hfsplus_ext_write_extent+0x536/0x620
[   70.240666][ T9350]  ? kmsan_get_metadata+0x13e/0x1c0
[   70.241175][ T9350]  __msan_warning+0x96/0x120
[   70.241645][ T9350]  __hfsplus_ext_cache_extent+0x7d0/0x990
[   70.242223][ T9350]  hfsplus_file_extend+0x74f/0x1cf0
[   70.242748][ T9350]  hfsplus_get_block+0xe16/0x17b0
[   70.243255][ T9350]  ? kmsan_internal_set_shadow_origin+0x77/0x110
[   70.243878][ T9350]  ? kmsan_get_metadata+0x13e/0x1c0
[   70.244400][ T9350]  ? kmsan_get_shadow_origin_ptr+0x4a/0xb0
[   70.244967][ T9350]  __block_write_begin_int+0x962/0x2ce0
[   70.245531][ T9350]  ? __pfx_hfsplus_get_block+0x10/0x10
[   70.246079][ T9350]  cont_write_begin+0x1000/0x1950
[   70.246598][ T9350]  hfsplus_write_begin+0x85/0x130
[   70.247105][ T9350]  ? __pfx_hfsplus_get_block+0x10/0x10
[   70.247650][ T9350]  ? __pfx_hfsplus_write_begin+0x10/0x10
[   70.248211][ T9350]  generic_perform_write+0x3e8/0x1060
[   70.248752][ T9350]  __generic_file_write_iter+0x215/0x460
[   70.249314][ T9350]  generic_file_write_iter+0x109/0x5e0
[   70.249856][ T9350]  ? kmsan_internal_set_shadow_origin+0x77/0x110
[   70.250487][ T9350]  vfs_write+0xb0f/0x14e0
[   70.250930][ T9350]  ? __pfx_generic_file_write_iter+0x10/0x10
[   70.251530][ T9350]  ksys_write+0x23e/0x490
[   70.251974][ T9350]  __x64_sys_write+0x97/0xf0
[   70.252450][ T9350]  x64_sys_call+0x3015/0x3cf0
[   70.252924][ T9350]  do_syscall_64+0xd9/0x1d0
[   70.253384][ T9350]  ? irqentry_exit+0x16/0x60
[   70.253844][ T9350]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[   70.254430][ T9350] RIP: 0033:0x7f7a92adffc9
[   70.254873][ T9350] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 48
[   70.256674][ T9350] RSP: 002b:00007fff0bca3188 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
[   70.257485][ T9350] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7a92adffc9
[   70.258246][ T9350] RDX: 000000000208e24b RSI: 0000000020000100 RDI: 0000000000000004
[   70.258998][ T9350] RBP: 00007fff0bca31a0 R08: 00007fff0bca31a0 R09: 00007fff0bca31a0
[   70.259769][ T9350] R10: 0000000000000000 R11: 0000000000000202 R12: 000055e0d75f8250
[   70.260520][ T9350] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[   70.261286][ T9350]  </TASK>
[   70.262026][ T9350] Kernel Offset: disabled

(gdb) l *__hfsplus_ext_cache_extent+0x7d0
0xffffffff8318aef0 is in __hfsplus_ext_cache_extent (fs/hfsplus/extents.c:168).
163		fd->key->ext.cnid = 0;
164		res = hfs_brec_find(fd, hfs_find_rec_by_key);
165		if (res && res != -ENOENT)
166			return res;
167		if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
168		    fd->key->ext.fork_type != fd->search_key->ext.fork_type)
169			return -ENOENT;
170		if (fd->entrylength != sizeof(hfsplus_extent_rec))
171			return -EIO;
172		hfs_bnode_read(fd->bnode, extent, fd->entryoffset,

The __hfsplus_ext_cache_extent() calls __hfsplus_ext_read_extent():

res = __hfsplus_ext_read_extent(fd, hip->cached_extents, inode->i_ino,
				block, HFSPLUS_IS_RSRC(inode) ?
					HFSPLUS_TYPE_RSRC :
					HFSPLUS_TYPE_DATA);

And if inode->i_ino could be equal to zero or any non-available CNID,
then hfs_brec_find() could not find the record in the tree. As a result,
fd->key could be compared with fd->search_key. But hfsplus_find_init()
uses kmalloc() for fd->key and fd->search_key allocation:

int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)
{
<skipped>
        ptr = kmalloc(tree->max_key_len * 2 + 4, GFP_KERNEL);
        if (!ptr)
                return -ENOMEM;
        fd->search_key = ptr;
        fd->key = ptr + tree->max_key_len + 2;
<skipped>
}

Finally, fd->key is still not initialized if hfs_brec_find()
has found nothing.

This patch changes kmalloc() on kzalloc() in hfs_find_init()
and intializes fd->record, fd->keyoffset, fd->keylength,
fd->entryoffset, fd->entrylength for the case if hfs_brec_find()
has been found nothing in the b-tree node.

Reported-by: syzbot <[email protected]>
Closes: https://syzkaller.appspot.com/bug?extid=55ad87f38795d6787521
Signed-off-by: Viacheslav Dubeyko <[email protected]>
cc: John Paul Adrian Glaubitz <[email protected]>
cc: Yangtao Li <[email protected]>
cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Viacheslav Dubeyko <[email protected]>
github-actions bot pushed a commit that referenced this pull request Oct 10, 2025
The test starts a workload and then opens events. If the events fail
to open, for example because of perf_event_paranoid, the gopipe of the
workload is leaked and the file descriptor leak check fails when the
test exits. To avoid this cancel the workload when opening the events
fails.

Before:
```
$ perf test -vv 7
  7: PERF_RECORD_* events & perf_sample fields:
 --- start ---
test child forked, pid 1189568
Using CPUID GenuineIntel-6-B7-1
 ------------------------------------------------------------
perf_event_attr:
  type                    	   0 (PERF_TYPE_HARDWARE)
  config                  	   0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                	   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
  exclude_kernel                   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 3
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
  exclude_kernel                   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 3
Attempt to add: software/cpu-clock/
..after resolving event: software/config=0/
cpu-clock -> software/cpu-clock/
 ------------------------------------------------------------
perf_event_attr:
  type                             1 (PERF_TYPE_SOFTWARE)
  size                             136
  config                           0x9 (PERF_COUNT_SW_DUMMY)
  sample_type                      IP|TID|TIME|CPU
  read_format                      ID|LOST
  disabled                         1
  inherit                          1
  mmap                             1
  comm                             1
  enable_on_exec                   1
  task                             1
  sample_id_all                    1
  mmap2                            1
  comm_exec                        1
  ksymbol                          1
  bpf_event                        1
  { wakeup_events, wakeup_watermark } 1
 ------------------------------------------------------------
sys_perf_event_open: pid 1189569  cpu 0  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
perf_evlist__open: Permission denied
 ---- end(-2) ----
Leak of file descriptor 6 that opened: 'pipe:[14200347]'
 ---- unexpected signal (6) ----
iFailed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
    #0 0x565358f6666e in child_test_sig_handler builtin-test.c:311
    #1 0x7f29ce849df0 in __restore_rt libc_sigaction.c:0
    #2 0x7f29ce89e95c in __pthread_kill_implementation pthread_kill.c:44
    #3 0x7f29ce849cc2 in raise raise.c:27
    #4 0x7f29ce8324ac in abort abort.c:81
    #5 0x565358f662d4 in check_leaks builtin-test.c:226
    #6 0x565358f6682e in run_test_child builtin-test.c:344
    #7 0x565358ef7121 in start_command run-command.c:128
    #8 0x565358f67273 in start_test builtin-test.c:545
    #9 0x565358f6771d in __cmd_test builtin-test.c:647
    #10 0x565358f682bd in cmd_test builtin-test.c:849
    #11 0x565358ee5ded in run_builtin perf.c:349
    #12 0x565358ee6085 in handle_internal_command perf.c:401
    #13 0x565358ee61de in run_argv perf.c:448
    #14 0x565358ee6527 in main perf.c:555
    #15 0x7f29ce833ca8 in __libc_start_call_main libc_start_call_main.h:74
    #16 0x7f29ce833d65 in __libc_start_main@@GLIBC_2.34 libc-start.c:128
    #17 0x565358e391c1 in _start perf[851c1]
  7: PERF_RECORD_* events & perf_sample fields                       : FAILED!
```

After:
```
$ perf test 7
  7: PERF_RECORD_* events & perf_sample fields                       : Skip (permissions)
```

Fixes: 16d00fe ("perf tests: Move test__PERF_RECORD into separate object")
Signed-off-by: Ian Rogers <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Athira Rajeev <[email protected]>
Cc: Chun-Tse Shao <[email protected]>
Cc: Howard Chu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
github-actions bot pushed a commit that referenced this pull request Oct 14, 2025
Phil reported a boot failure once sheaves become used in commits
59faa4d ("maple_tree: use percpu sheaves for maple_node_cache") and
3accabd ("mm, vma: use percpu sheaves for vm_area_struct cache"):

 BUG: kernel NULL pointer dereference, address: 0000000000000040
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: Oops: 0000 [#1] SMP NOPTI
 CPU: 21 UID: 0 PID: 818 Comm: kworker/u398:0 Not tainted 6.17.0-rc3.slab+ #5 PREEMPT(voluntary)
 Hardware name: Dell Inc. PowerEdge R7425/02MJ3T, BIOS 1.26.0 07/30/2025
 RIP: 0010:__pcs_replace_empty_main+0x44/0x1d0
 Code: ec 08 48 8b 46 10 48 8b 76 08 48 85 c0 74 0b 8b 48 18 85 c9 0f 85 e5 00 00 00 65 48 63 05 e4 ee 50 02 49 8b 84 c6 e0 00 00 00 <4c> 8b 68 40 4c 89 ef e8 b0 81 ff ff 48 89 c5 48 85 c0 74 1d 48 89
 RSP: 0018:ffffd2d10950bdb0 EFLAGS: 00010246
 RAX: 0000000000000000 RBX: ffff8a775dab74b0 RCX: 00000000ffffffff
 RDX: 0000000000000cc0 RSI: ffff8a6800804000 RDI: ffff8a680004e300
 RBP: ffffd2d10950be40 R08: 0000000000000060 R09: ffffffffb9367388
 R10: 00000000000149e8 R11: ffff8a6f87a38000 R12: 0000000000000cc0
 R13: 0000000000000cc0 R14: ffff8a680004e300 R15: 00000000000000c0
 FS:  0000000000000000(0000) GS:ffff8a77a3541000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000040 CR3: 0000000e1aa24000 CR4: 00000000003506f0
 Call Trace:
  <TASK>
  ? srso_return_thunk+0x5/0x5f
  ? vm_area_alloc+0x1e/0x60
  kmem_cache_alloc_noprof+0x4ec/0x5b0
  vm_area_alloc+0x1e/0x60
  create_init_stack_vma+0x26/0x210
  alloc_bprm+0x139/0x200
  kernel_execve+0x4a/0x140
  call_usermodehelper_exec_async+0xd0/0x190
  ? __pfx_call_usermodehelper_exec_async+0x10/0x10
  ret_from_fork+0xf0/0x110
  ? __pfx_call_usermodehelper_exec_async+0x10/0x10
  ret_from_fork_asm+0x1a/0x30
  </TASK>
 Modules linked in:
 CR2: 0000000000000040
 ---[ end trace 0000000000000000 ]---
 RIP: 0010:__pcs_replace_empty_main+0x44/0x1d0
 Code: ec 08 48 8b 46 10 48 8b 76 08 48 85 c0 74 0b 8b 48 18 85 c9 0f 85 e5 00 00 00 65 48 63 05 e4 ee 50 02 49 8b 84 c6 e0 00 00 00 <4c> 8b 68 40 4c 89 ef e8 b0 81 ff ff 48 89 c5 48 85 c0 74 1d 48 89
 RSP: 0018:ffffd2d10950bdb0 EFLAGS: 00010246
 RAX: 0000000000000000 RBX: ffff8a775dab74b0 RCX: 00000000ffffffff
 RDX: 0000000000000cc0 RSI: ffff8a6800804000 RDI: ffff8a680004e300
 RBP: ffffd2d10950be40 R08: 0000000000000060 R09: ffffffffb9367388
 R10: 00000000000149e8 R11: ffff8a6f87a38000 R12: 0000000000000cc0
 R13: 0000000000000cc0 R14: ffff8a680004e300 R15: 00000000000000c0
 FS:  0000000000000000(0000) GS:ffff8a77a3541000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000040 CR3: 0000000e1aa24000 CR4: 00000000003506f0
 Kernel panic - not syncing: Fatal exception
 Kernel Offset: 0x36a00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
 ---[ end Kernel panic - not syncing: Fatal exception ]---

And noted "this is an AMD EPYC 7401 with 8 NUMA nodes configured such
that memory is only on 2 of them."

 # numactl --hardware
 available: 8 nodes (0-7)
 node 0 cpus: 0 8 16 24 32 40 48 56 64 72 80 88
 node 0 size: 0 MB
 node 0 free: 0 MB
 node 1 cpus: 2 10 18 26 34 42 50 58 66 74 82 90
 node 1 size: 31584 MB
 node 1 free: 30397 MB
 node 2 cpus: 4 12 20 28 36 44 52 60 68 76 84 92
 node 2 size: 0 MB
 node 2 free: 0 MB
 node 3 cpus: 6 14 22 30 38 46 54 62 70 78 86 94
 node 3 size: 0 MB
 node 3 free: 0 MB
 node 4 cpus: 1 9 17 25 33 41 49 57 65 73 81 89
 node 4 size: 0 MB
 node 4 free: 0 MB
 node 5 cpus: 3 11 19 27 35 43 51 59 67 75 83 91
 node 5 size: 32214 MB
 node 5 free: 31625 MB
 node 6 cpus: 5 13 21 29 37 45 53 61 69 77 85 93
 node 6 size: 0 MB
 node 6 free: 0 MB
 node 7 cpus: 7 15 23 31 39 47 55 63 71 79 87 95
 node 7 size: 0 MB
 node 7 free: 0 MB

Linus decoded the stacktrace to get_barn() and get_node() and determined
that kmem_cache->node[numa_mem_id()] is NULL.

The problem is due to a wrong assumption that memoryless nodes only
exist on systems with CONFIG_HAVE_MEMORYLESS_NODES, where numa_mem_id()
points to the nearest node that has memory. SLUB has been allocating its
kmem_cache_node structures only on nodes with memory and so it does with
struct node_barn.

For kmem_cache_node, get_partial_node() checks if get_node() result is
not NULL, which I assumed was for protection from a bogus node id passed
to kmalloc_node() but apparently it's also for systems where
numa_mem_id() (used when no specific node is given) might return a
memoryless node.

Fix the sheaves code the same way by checking the result of get_node()
and bailing out if it's NULL. Note that cpus on such memoryless nodes
will have degraded sheaves performance, which can be improved later,
preferably by making numa_mem_id() work properly on such systems.

Fixes: 2d517aa ("slab: add opt-in caching layer of percpu sheaves")
Reported-and-tested-by: Phil Auld <[email protected]>
Closes: https://lore.kernel.org/all/[email protected]/
Analyzed-by: Linus Torvalds <[email protected]>
Link: https://lore.kernel.org/all/CAHk-%3Dwg1xK%2BBr%3DFJ5QipVhzCvq7uQVPt5Prze6HDhQQ%[email protected]/
Signed-off-by: Vlastimil Babka <[email protected]>
github-actions bot pushed a commit that referenced this pull request Oct 25, 2025
… 'T'

When perf report with annotation for a symbol, press 's' and 'T', then exit
the annotate browser. Once annotate the same symbol, the annotate browser
will crash.

The browser.arch was required to be correctly updated when data type
feature was enabled by 'T'. Usually it was initialized by symbol__annotate2
function. If a symbol has already been correctly annotated at the first
time, it should not call the symbol__annotate2 function again, thus the
browser.arch will not get initialized. Then at the second time to show the
annotate browser, the data type needs to be displayed but the browser.arch
is empty.

Stack trace as below:

Perf: Segmentation fault
-------- backtrace --------
    #0 0x55d365 in ui__signal_backtrace setup.c:0
    #1 0x7f5ff1a3e930 in __restore_rt libc.so.6[3e930]
    #2 0x570f08 in arch__is perf[570f08]
    #3 0x562186 in annotate_get_insn_location perf[562186]
    #4 0x562626 in __hist_entry__get_data_type annotate.c:0
    #5 0x56476d in annotation_line__write perf[56476d]
    #6 0x54e2db in annotate_browser__write annotate.c:0
    #7 0x54d061 in ui_browser__list_head_refresh perf[54d061]
    #8 0x54dc9e in annotate_browser__refresh annotate.c:0
    #9 0x54c03d in __ui_browser__refresh browser.c:0
    #10 0x54ccf8 in ui_browser__run perf[54ccf8]
    #11 0x54eb92 in __hist_entry__tui_annotate perf[54eb92]
    #12 0x552293 in do_annotate hists.c:0
    #13 0x55941c in evsel__hists_browse hists.c:0
    #14 0x55b00f in evlist__tui_browse_hists perf[55b00f]
    #15 0x42ff02 in cmd_report perf[42ff02]
    #16 0x494008 in run_builtin perf.c:0
    #17 0x494305 in handle_internal_command perf.c:0
    #18 0x410547 in main perf[410547]
    #19 0x7f5ff1a295d0 in __libc_start_call_main libc.so.6[295d0]
    #20 0x7f5ff1a29680 in __libc_start_main@@GLIBC_2.34 libc.so.6[29680]
    #21 0x410b75 in _start perf[410b75]

Fixes: 1d4374a ("perf annotate: Add 'T' hot key to toggle data type display")
Reviewed-by: James Clark <[email protected]>
Tested-by: Namhyung Kim <[email protected]>
Signed-off-by: Tianyou Li <[email protected]>
Signed-off-by: Namhyung Kim <[email protected]>
github-actions bot pushed a commit that referenced this pull request Nov 5, 2025
On completion of i915_vma_pin_ww(), a synchronous variant of
dma_fence_work_commit() is called.  When pinning a VMA to GGTT address
space on a Cherry View family processor, or on a Broxton generation SoC
with VTD enabled, i.e., when stop_machine() is then called from
intel_ggtt_bind_vma(), that can potentially lead to lock inversion among
reservation_ww and cpu_hotplug locks.

[86.861179] ======================================================
[86.861193] WARNING: possible circular locking dependency detected
[86.861209] 6.15.0-rc5-CI_DRM_16515-gca0305cadc2d+ #1 Tainted: G     U
[86.861226] ------------------------------------------------------
[86.861238] i915_module_loa/1432 is trying to acquire lock:
[86.861252] ffffffff83489090 (cpu_hotplug_lock){++++}-{0:0}, at: stop_machine+0x1c/0x50
[86.861290]
but task is already holding lock:
[86.861303] ffffc90002e0b4c8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_vma_pin.constprop.0+0x39/0x1d0 [i915]
[86.862233]
which lock already depends on the new lock.
[86.862251]
the existing dependency chain (in reverse order) is:
[86.862265]
-> #5 (reservation_ww_class_mutex){+.+.}-{3:3}:
[86.862292]        dma_resv_lockdep+0x19a/0x390
[86.862315]        do_one_initcall+0x60/0x3f0
[86.862334]        kernel_init_freeable+0x3cd/0x680
[86.862353]        kernel_init+0x1b/0x200
[86.862369]        ret_from_fork+0x47/0x70
[86.862383]        ret_from_fork_asm+0x1a/0x30
[86.862399]
-> #4 (reservation_ww_class_acquire){+.+.}-{0:0}:
[86.862425]        dma_resv_lockdep+0x178/0x390
[86.862440]        do_one_initcall+0x60/0x3f0
[86.862454]        kernel_init_freeable+0x3cd/0x680
[86.862470]        kernel_init+0x1b/0x200
[86.862482]        ret_from_fork+0x47/0x70
[86.862495]        ret_from_fork_asm+0x1a/0x30
[86.862509]
-> #3 (&mm->mmap_lock){++++}-{3:3}:
[86.862531]        down_read_killable+0x46/0x1e0
[86.862546]        lock_mm_and_find_vma+0xa2/0x280
[86.862561]        do_user_addr_fault+0x266/0x8e0
[86.862578]        exc_page_fault+0x8a/0x2f0
[86.862593]        asm_exc_page_fault+0x27/0x30
[86.862607]        filldir64+0xeb/0x180
[86.862620]        kernfs_fop_readdir+0x118/0x480
[86.862635]        iterate_dir+0xcf/0x2b0
[86.862648]        __x64_sys_getdents64+0x84/0x140
[86.862661]        x64_sys_call+0x1058/0x2660
[86.862675]        do_syscall_64+0x91/0xe90
[86.862689]        entry_SYSCALL_64_after_hwframe+0x76/0x7e
[86.862703]
-> #2 (&root->kernfs_rwsem){++++}-{3:3}:
[86.862725]        down_write+0x3e/0xf0
[86.862738]        kernfs_add_one+0x30/0x3c0
[86.862751]        kernfs_create_dir_ns+0x53/0xb0
[86.862765]        internal_create_group+0x134/0x4c0
[86.862779]        sysfs_create_group+0x13/0x20
[86.862792]        topology_add_dev+0x1d/0x30
[86.862806]        cpuhp_invoke_callback+0x4b5/0x850
[86.862822]        cpuhp_issue_call+0xbf/0x1f0
[86.862836]        __cpuhp_setup_state_cpuslocked+0x111/0x320
[86.862852]        __cpuhp_setup_state+0xb0/0x220
[86.862866]        topology_sysfs_init+0x30/0x50
[86.862879]        do_one_initcall+0x60/0x3f0
[86.862893]        kernel_init_freeable+0x3cd/0x680
[86.862908]        kernel_init+0x1b/0x200
[86.862921]        ret_from_fork+0x47/0x70
[86.862934]        ret_from_fork_asm+0x1a/0x30
[86.862947]
-> #1 (cpuhp_state_mutex){+.+.}-{3:3}:
[86.862969]        __mutex_lock+0xaa/0xed0
[86.862982]        mutex_lock_nested+0x1b/0x30
[86.862995]        __cpuhp_setup_state_cpuslocked+0x67/0x320
[86.863012]        __cpuhp_setup_state+0xb0/0x220
[86.863026]        page_alloc_init_cpuhp+0x2d/0x60
[86.863041]        mm_core_init+0x22/0x2d0
[86.863054]        start_kernel+0x576/0xbd0
[86.863068]        x86_64_start_reservations+0x18/0x30
[86.863084]        x86_64_start_kernel+0xbf/0x110
[86.863098]        common_startup_64+0x13e/0x141
[86.863114]
-> #0 (cpu_hotplug_lock){++++}-{0:0}:
[86.863135]        __lock_acquire+0x1635/0x2810
[86.863152]        lock_acquire+0xc4/0x2f0
[86.863166]        cpus_read_lock+0x41/0x100
[86.863180]        stop_machine+0x1c/0x50
[86.863194]        bxt_vtd_ggtt_insert_entries__BKL+0x3b/0x60 [i915]
[86.863987]        intel_ggtt_bind_vma+0x43/0x70 [i915]
[86.864735]        __vma_bind+0x55/0x70 [i915]
[86.865510]        fence_work+0x26/0xa0 [i915]
[86.866248]        fence_notify+0xa1/0x140 [i915]
[86.866983]        __i915_sw_fence_complete+0x8f/0x270 [i915]
[86.867719]        i915_sw_fence_commit+0x39/0x60 [i915]
[86.868453]        i915_vma_pin_ww+0x462/0x1360 [i915]
[86.869228]        i915_vma_pin.constprop.0+0x133/0x1d0 [i915]
[86.870001]        initial_plane_vma+0x307/0x840 [i915]
[86.870774]        intel_initial_plane_config+0x33f/0x670 [i915]
[86.871546]        intel_display_driver_probe_nogem+0x1c6/0x260 [i915]
[86.872330]        i915_driver_probe+0x7fa/0xe80 [i915]
[86.873057]        i915_pci_probe+0xe6/0x220 [i915]
[86.873782]        local_pci_probe+0x47/0xb0
[86.873802]        pci_device_probe+0xf3/0x260
[86.873817]        really_probe+0xf1/0x3c0
[86.873833]        __driver_probe_device+0x8c/0x180
[86.873848]        driver_probe_device+0x24/0xd0
[86.873862]        __driver_attach+0x10f/0x220
[86.873876]        bus_for_each_dev+0x7f/0xe0
[86.873892]        driver_attach+0x1e/0x30
[86.873904]        bus_add_driver+0x151/0x290
[86.873917]        driver_register+0x5e/0x130
[86.873931]        __pci_register_driver+0x7d/0x90
[86.873945]        i915_pci_register_driver+0x23/0x30 [i915]
[86.874678]        i915_init+0x37/0x120 [i915]
[86.875347]        do_one_initcall+0x60/0x3f0
[86.875369]        do_init_module+0x97/0x2a0
[86.875385]        load_module+0x2c54/0x2d80
[86.875398]        init_module_from_file+0x96/0xe0
[86.875413]        idempotent_init_module+0x117/0x330
[86.875426]        __x64_sys_finit_module+0x77/0x100
[86.875440]        x64_sys_call+0x24de/0x2660
[86.875454]        do_syscall_64+0x91/0xe90
[86.875470]        entry_SYSCALL_64_after_hwframe+0x76/0x7e
[86.875486]
other info that might help us debug this:
[86.875502] Chain exists of:
  cpu_hotplug_lock --> reservation_ww_class_acquire --> reservation_ww_class_mutex
[86.875539]  Possible unsafe locking scenario:
[86.875552]        CPU0                    CPU1
[86.875563]        ----                    ----
[86.875573]   lock(reservation_ww_class_mutex);
[86.875588]                                lock(reservation_ww_class_acquire);
[86.875606]                                lock(reservation_ww_class_mutex);
[86.875624]   rlock(cpu_hotplug_lock);
[86.875637]
 *** DEADLOCK ***
[86.875650] 3 locks held by i915_module_loa/1432:
[86.875663]  #0: ffff888101f5c1b0 (&dev->mutex){....}-{3:3}, at: __driver_attach+0x104/0x220
[86.875699]  #1: ffffc90002e0b4a0 (reservation_ww_class_acquire){+.+.}-{0:0}, at: i915_vma_pin.constprop.0+0x39/0x1d0 [i915]
[86.876512]  #2: ffffc90002e0b4c8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_vma_pin.constprop.0+0x39/0x1d0 [i915]
[86.877305]
stack backtrace:
[86.877326] CPU: 0 UID: 0 PID: 1432 Comm: i915_module_loa Tainted: G     U              6.15.0-rc5-CI_DRM_16515-gca0305cadc2d+ #1 PREEMPT(voluntary)
[86.877334] Tainted: [U]=USER
[86.877336] Hardware name:  /NUC5CPYB, BIOS PYBSWCEL.86A.0079.2020.0420.1316 04/20/2020
[86.877339] Call Trace:
[86.877344]  <TASK>
[86.877353]  dump_stack_lvl+0x91/0xf0
[86.877364]  dump_stack+0x10/0x20
[86.877369]  print_circular_bug+0x285/0x360
[86.877379]  check_noncircular+0x135/0x150
[86.877390]  __lock_acquire+0x1635/0x2810
[86.877403]  lock_acquire+0xc4/0x2f0
[86.877408]  ? stop_machine+0x1c/0x50
[86.877422]  ? __pfx_bxt_vtd_ggtt_insert_entries__cb+0x10/0x10 [i915]
[86.878173]  cpus_read_lock+0x41/0x100
[86.878182]  ? stop_machine+0x1c/0x50
[86.878191]  ? __pfx_bxt_vtd_ggtt_insert_entries__cb+0x10/0x10 [i915]
[86.878916]  stop_machine+0x1c/0x50
[86.878927]  bxt_vtd_ggtt_insert_entries__BKL+0x3b/0x60 [i915]
[86.879652]  intel_ggtt_bind_vma+0x43/0x70 [i915]
[86.880375]  __vma_bind+0x55/0x70 [i915]
[86.881133]  fence_work+0x26/0xa0 [i915]
[86.881851]  fence_notify+0xa1/0x140 [i915]
[86.882566]  __i915_sw_fence_complete+0x8f/0x270 [i915]
[86.883286]  i915_sw_fence_commit+0x39/0x60 [i915]
[86.884003]  i915_vma_pin_ww+0x462/0x1360 [i915]
[86.884756]  ? i915_vma_pin.constprop.0+0x6c/0x1d0 [i915]
[86.885513]  i915_vma_pin.constprop.0+0x133/0x1d0 [i915]
[86.886281]  initial_plane_vma+0x307/0x840 [i915]
[86.887049]  intel_initial_plane_config+0x33f/0x670 [i915]
[86.887819]  intel_display_driver_probe_nogem+0x1c6/0x260 [i915]
[86.888587]  i915_driver_probe+0x7fa/0xe80 [i915]
[86.889293]  ? mutex_unlock+0x12/0x20
[86.889301]  ? drm_privacy_screen_get+0x171/0x190
[86.889308]  ? acpi_dev_found+0x66/0x80
[86.889321]  i915_pci_probe+0xe6/0x220 [i915]
[86.890038]  local_pci_probe+0x47/0xb0
[86.890049]  pci_device_probe+0xf3/0x260
[86.890058]  really_probe+0xf1/0x3c0
[86.890067]  __driver_probe_device+0x8c/0x180
[86.890072]  driver_probe_device+0x24/0xd0
[86.890078]  __driver_attach+0x10f/0x220
[86.890083]  ? __pfx___driver_attach+0x10/0x10
[86.890088]  bus_for_each_dev+0x7f/0xe0
[86.890097]  driver_attach+0x1e/0x30
[86.890101]  bus_add_driver+0x151/0x290
[86.890107]  driver_register+0x5e/0x130
[86.890113]  __pci_register_driver+0x7d/0x90
[86.890119]  i915_pci_register_driver+0x23/0x30 [i915]
[86.890833]  i915_init+0x37/0x120 [i915]
[86.891482]  ? __pfx_i915_init+0x10/0x10 [i915]
[86.892135]  do_one_initcall+0x60/0x3f0
[86.892145]  ? __kmalloc_cache_noprof+0x33f/0x470
[86.892157]  do_init_module+0x97/0x2a0
[86.892164]  load_module+0x2c54/0x2d80
[86.892168]  ? __kernel_read+0x15c/0x300
[86.892185]  ? kernel_read_file+0x2b1/0x320
[86.892195]  init_module_from_file+0x96/0xe0
[86.892199]  ? init_module_from_file+0x96/0xe0
[86.892211]  idempotent_init_module+0x117/0x330
[86.892224]  __x64_sys_finit_module+0x77/0x100
[86.892230]  x64_sys_call+0x24de/0x2660
[86.892236]  do_syscall_64+0x91/0xe90
[86.892243]  ? irqentry_exit+0x77/0xb0
[86.892249]  ? sysvec_apic_timer_interrupt+0x57/0xc0
[86.892256]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[86.892261] RIP: 0033:0x7303e1b2725d
[86.892271] Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 8b bb 0d 00 f7 d8 64 89 01 48
[86.892276] RSP: 002b:00007ffddd1fdb38 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[86.892281] RAX: ffffffffffffffda RBX: 00005d771d88fd90 RCX: 00007303e1b2725d
[86.892285] RDX: 0000000000000000 RSI: 00005d771d893aa0 RDI: 000000000000000c
[86.892287] RBP: 00007ffddd1fdbf0 R08: 0000000000000040 R09: 00007ffddd1fdb80
[86.892289] R10: 00007303e1c03b20 R11: 0000000000000246 R12: 00005d771d893aa0
[86.892292] R13: 0000000000000000 R14: 00005d771d88f0d0 R15: 00005d771d895710
[86.892304]  </TASK>

Call asynchronous variant of dma_fence_work_commit() in that case.

v3: Provide more verbose in-line comment (Andi),
  - mention target environments in commit message.

Fixes: 7d1c261 ("drm/i915: Take reservation lock around i915_vma_pin.")
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14985
Cc: Andi Shyti <[email protected]>
Signed-off-by: Janusz Krzysztofik <[email protected]>
Reviewed-by: Sebastian Brzezinka <[email protected]>
Reviewed-by: Krzysztof Karas <[email protected]>
Acked-by: Andi Shyti <[email protected]>
Signed-off-by: Andi Shyti <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
(cherry picked from commit 648ef13)
Signed-off-by: Rodrigo Vivi <[email protected]>
github-actions bot pushed a commit that referenced this pull request Nov 5, 2025
When using perf record with the `--overwrite` option, a segmentation fault
occurs if an event fails to open. For example:

  perf record -e cycles-ct -F 1000 -a --overwrite
  Error:
  cycles-ct:H: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'
  perf: Segmentation fault
      #0 0x6466b6 in dump_stack debug.c:366
      #1 0x646729 in sighandler_dump_stack debug.c:378
      #2 0x453fd1 in sigsegv_handler builtin-record.c:722
      #3 0x7f8454e65090 in __restore_rt libc-2.32.so[54090]
      #4 0x6c5671 in __perf_event__synthesize_id_index synthetic-events.c:1862
      #5 0x6c5ac0 in perf_event__synthesize_id_index synthetic-events.c:1943
      #6 0x458090 in record__synthesize builtin-record.c:2075
      #7 0x45a85a in __cmd_record builtin-record.c:2888
      #8 0x45deb6 in cmd_record builtin-record.c:4374
      #9 0x4e5e33 in run_builtin perf.c:349
      #10 0x4e60bf in handle_internal_command perf.c:401
      #11 0x4e6215 in run_argv perf.c:448
      #12 0x4e653a in main perf.c:555
      #13 0x7f8454e4fa72 in __libc_start_main libc-2.32.so[3ea72]
      #14 0x43a3ee in _start ??:0

The --overwrite option implies --tail-synthesize, which collects non-sample
events reflecting the system status when recording finishes. However, when
evsel opening fails (e.g., unsupported event 'cycles-ct'), session->evlist
is not initialized and remains NULL. The code unconditionally calls
record__synthesize() in the error path, which iterates through the NULL
evlist pointer and causes a segfault.

To fix it, move the record__synthesize() call inside the error check block, so
it's only called when there was no error during recording, ensuring that evlist
is properly initialized.

Fixes: 4ea648a ("perf record: Add --tail-synthesize option")
Signed-off-by: Shuai Xue <[email protected]>
Signed-off-by: Namhyung Kim <[email protected]>
github-actions bot pushed a commit that referenced this pull request Nov 6, 2025
With CONFIG_PROVE_RCU_LIST=y and by executing

  $ netcat -l --sctp &
  $ netcat --sctp localhost &
  $ ss --sctp

one can trigger the following Lockdep-RCU splat(s):

  WARNING: suspicious RCU usage
  6.18.0-rc1-00093-g7f864458e9a6 #5 Not tainted
  -----------------------------
  net/sctp/diag.c:76 RCU-list traversed in non-reader section!!

  other info that might help us debug this:

  rcu_scheduler_active = 2, debug_locks = 1
  2 locks held by ss/215:
   #0: ffff9c740828bec0 (nlk_cb_mutex-SOCK_DIAG){+.+.}-{4:4}, at: __netlink_dump_start+0x84/0x2b0
   #1: ffff9c7401d72cd0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: sctp_sock_dump+0x38/0x200

  stack backtrace:
  CPU: 0 UID: 0 PID: 215 Comm: ss Not tainted 6.18.0-rc1-00093-g7f864458e9a6 #5 PREEMPT(voluntary)
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
  Call Trace:
   <TASK>
   dump_stack_lvl+0x5d/0x90
   lockdep_rcu_suspicious.cold+0x4e/0xa3
   inet_sctp_diag_fill.isra.0+0x4b1/0x5d0
   sctp_sock_dump+0x131/0x200
   sctp_transport_traverse_process+0x170/0x1b0
   ? __pfx_sctp_sock_filter+0x10/0x10
   ? __pfx_sctp_sock_dump+0x10/0x10
   sctp_diag_dump+0x103/0x140
   __inet_diag_dump+0x70/0xb0
   netlink_dump+0x148/0x490
   __netlink_dump_start+0x1f3/0x2b0
   inet_diag_handler_cmd+0xcd/0x100
   ? __pfx_inet_diag_dump_start+0x10/0x10
   ? __pfx_inet_diag_dump+0x10/0x10
   ? __pfx_inet_diag_dump_done+0x10/0x10
   sock_diag_rcv_msg+0x18e/0x320
   ? __pfx_sock_diag_rcv_msg+0x10/0x10
   netlink_rcv_skb+0x4d/0x100
   netlink_unicast+0x1d7/0x2b0
   netlink_sendmsg+0x203/0x450
   ____sys_sendmsg+0x30c/0x340
   ___sys_sendmsg+0x94/0xf0
   __sys_sendmsg+0x83/0xf0
   do_syscall_64+0xbb/0x390
   entry_SYSCALL_64_after_hwframe+0x77/0x7f
   ...
   </TASK>

Fixes: 8f840e4 ("sctp: add the sctp_diag.c file")
Signed-off-by: Stefan Wiehler <[email protected]>
Reviewed-by: Kuniyuki Iwashima <[email protected]>
Acked-by: Xin Long <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
github-actions bot pushed a commit that referenced this pull request Nov 7, 2025
Michael Chan says:

====================
bnxt_en: Bug fixes

Patches 1, 3, and 4 are bug fixes related to the FW log tracing driver
coredump feature recently added in 6.13.  Patch #1 adds the necessary
call to shutdown the FW logging DMA during PCI shutdown.  Patch #3 fixes
a possible null pointer derefernce when using early versions of the FW
with this feature.  Patch #4 adds the coredump header information
unconditionally to make it more robust.

Patch #2 fixes a possible memory leak during PTP shutdown.  Patch #5
eliminates a dmesg warning when doing devlink reload.
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
github-actions bot pushed a commit that referenced this pull request Nov 14, 2025
The one_time_gc field in struct victim_sel_policy is conditionally
initialized but unconditionally read, leading to undefined behavior
that triggers UBSAN warnings.

In f2fs_get_victim() at fs/f2fs/gc.c:774, the victim_sel_policy
structure is declared without initialization:

    struct victim_sel_policy p;

The field p.one_time_gc is only assigned when the 'one_time' parameter
is true (line 789):

    if (one_time) {
        p.one_time_gc = one_time;
        ...
    }

However, this field is unconditionally read in subsequent get_gc_cost()
at line 395:

    if (p->one_time_gc && (valid_thresh_ratio < 100) && ...)

When one_time is false, p.one_time_gc contains uninitialized stack
memory. Hence p.one_time_gc is an invalid bool value.

UBSAN detects this invalid bool value:

    UBSAN: invalid-load in fs/f2fs/gc.c:395:7
    load of value 77 is not a valid value for type '_Bool'
    CPU: 3 UID: 0 PID: 1297 Comm: f2fs_gc-252:16 Not tainted 6.18.0-rc3
    #5 PREEMPT(voluntary)
    Hardware name: OpenStack Foundation OpenStack Nova,
    BIOS 1.13.0-1ubuntu1.1 04/01/2014
    Call Trace:
     <TASK>
     dump_stack_lvl+0x70/0x90
     dump_stack+0x14/0x20
     __ubsan_handle_load_invalid_value+0xb3/0xf0
     ? dl_server_update+0x2e/0x40
     ? update_curr+0x147/0x170
     f2fs_get_victim.cold+0x66/0x134 [f2fs]
     ? sched_balance_newidle+0x2ca/0x470
     ? finish_task_switch.isra.0+0x8d/0x2a0
     f2fs_gc+0x2ba/0x8e0 [f2fs]
     ? _raw_spin_unlock_irqrestore+0x12/0x40
     ? __timer_delete_sync+0x80/0xe0
     ? timer_delete_sync+0x14/0x20
     ? schedule_timeout+0x82/0x100
     gc_thread_func+0x38b/0x860 [f2fs]
     ? gc_thread_func+0x38b/0x860 [f2fs]
     ? __pfx_autoremove_wake_function+0x10/0x10
     kthread+0x10b/0x220
     ? __pfx_gc_thread_func+0x10/0x10 [f2fs]
     ? _raw_spin_unlock_irq+0x12/0x40
     ? __pfx_kthread+0x10/0x10
     ret_from_fork+0x11a/0x160
     ? __pfx_kthread+0x10/0x10
     ret_from_fork_asm+0x1a/0x30
     </TASK>

This issue is reliably reproducible with the following steps on a
100GB SSD /dev/vdb:

    mkfs.f2fs -f /dev/vdb
    mount /dev/vdb /mnt/f2fs_test
    fio --name=gc --directory=/mnt/f2fs_test --rw=randwrite \
        --bs=4k --size=8G --numjobs=12 --fsync=4 --runtime=10 \
        --time_based
    echo 1 > /sys/fs/f2fs/vdb/gc_urgent

The uninitialized value causes incorrect GC victim selection, leading
to unpredictable garbage collection behavior.

Fix by zero-initializing the entire victim_sel_policy structure to
ensure all fields have defined values.

Fixes: e791d00 ("f2fs: add valid block ratio not to do excessive GC for one time GC")
Cc: [email protected]
Signed-off-by: Xiaole He <[email protected]>
Reviewed-by: Chao Yu <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>
github-actions bot pushed a commit that referenced this pull request Nov 18, 2025
When the system has many cores and task switching is frequent,
setting set_ftrace_pid can cause frequent pid_list->lock contention
and high system sys usage.

For example, in a 288-core VM environment, we observed 267 CPUs
experiencing contention on pid_list->lock, with stack traces showing:

 #4 [ffffa6226fb4bc70] native_queued_spin_lock_slowpath at ffffffff99cd4b7e
 #5 [ffffa6226fb4bc90] _raw_spin_lock_irqsave at ffffffff99cd3e36
 #6 [ffffa6226fb4bca0] trace_pid_list_is_set at ffffffff99267554
 #7 [ffffa6226fb4bcc0] trace_ignore_this_task at ffffffff9925c288
 #8 [ffffa6226fb4bcd8] ftrace_filter_pid_sched_switch_probe at ffffffff99246efe
 #9 [ffffa6226fb4bcf0] __schedule at ffffffff99ccd161

Replaces the existing spinlock with a seqlock to allow concurrent readers,
while maintaining write exclusivity.

Link: https://patch.msgid.link/[email protected]
Reviewed-by: Huang Cun <[email protected]>
Signed-off-by: Yongliang Gao <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
github-actions bot pushed a commit that referenced this pull request Nov 29, 2025
Marc Kleine-Budde <[email protected]> says:

Similarly to how CAN FD reuses the bittiming logic of Classical CAN, CAN XL
also reuses the entirety of CAN FD features, and, on top of that, adds new
features which are specific to CAN XL.

A so-called 'mixed-mode' is intended to have (XL-tolerant) CAN FD nodes and
CAN XL nodes on one CAN segment, where the FD-controllers can talk CC/FD
and the XL-controllers can talk CC/FD/XL. This mixed-mode utilizes the
known error-signalling (ES) for sending CC/FD/XL frames. For CAN FD and CAN
XL the tranceiver delay compensation (TDC) is supported to use common CAN
and CAN-SIG transceivers.

The CANXL-only mode disables the error-signalling in the CAN XL controller.
This mode does not allow CC/FD frames to be sent but additionally offers a
CAN XL transceiver mode switching (TMS) to send CAN XL frames with up to
20Mbit/s data rate. The TMS utilizes a PWM configuration which is added to
the netlink interface.

Configured with CAN_CTRLMODE_FD and CAN_CTRLMODE_XL this leads to:

FD=0 XL=0 CC-only mode         (ES=1)
FD=1 XL=0 FD/CC mixed-mode     (ES=1)
FD=1 XL=1 XL/FD/CC mixed-mode  (ES=1)
FD=0 XL=1 XL-only mode         (ES=0, TMS optional)

Patch #1 print defined ctrlmode strings capitalized to increase the
readability and to be in line with the 'ip' tool (iproute2).

Patch #2 is a small clean-up which makes can_calc_bittiming() use
NL_SET_ERR_MSG() instead of netdev_err().

Patch #3 adds a check in can_dev_dropped_skb() to drop CAN FD frames
when CAN FD is turned off.

Patch #4 adds CAN_CTRLMODE_RESTRICTED. Note that contrary to the other
CAN_CTRL_MODE_XL_* that are introduced in the later patches, this control
mode is not specific to CAN XL. The nuance is that because this restricted
mode was only added in ISO 11898-1:2024, it is made mandatory for CAN XL
devices but optional for other protocols. This is why this patch is added
as a preparation before introducing the core CAN XL logic.

Patch #5 adds all the CAN XL features which are inherited from CAN FD: the
nominal bittiming, the data bittiming and the TDC.

Patch #6 add a new CAN_CTRLMODE_XL_TMS control mode which is specific to
CAN XL to enable the transceiver mode switching (TMS) in XL-only mode.

Patch #7 adds a check in can_dev_dropped_skb() to drop CAN CC/FD frames
when the CAN XL controller is in CAN XL-only mode. The introduced
can_dev_in_xl_only_mode() function also determines the error-signalling
configuration for the CAN XL controllers.

Patch #8 to #11 add the PWM logic for the CAN XL TMS mode.

Patch #12 to #14 add different default sample-points for standard CAN and
CAN SIG transceivers (with TDC) and CAN XL transceivers using PWM in the
CAN XL TMS mode.

Patch #15 add a dummy_can driver for netlink testing and debugging.

Patch #16 check CAN frame type (CC/FD/XL) when writing those frames to the
CAN_RAW socket and reject them if it's not supported by the CAN interface.

Patch #17 increase the resolution when printing the bitrate error and
round-up the value to 0.01% in the case the resolution would still provide
values which would lead to 0.00%.

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Marc Kleine-Budde <[email protected]>
github-actions bot pushed a commit that referenced this pull request Dec 6, 2025
When interrupting perf stat in repeat mode with a signal the signal is
passed to the child process but the repeat doesn't terminate:
```
$ perf stat -v --null --repeat 10 sleep 1
Control descriptor is not initialized
[ perf stat: executing run #1 ... ]
[ perf stat: executing run #2 ... ]
^Csleep: Interrupt
[ perf stat: executing run #3 ... ]
[ perf stat: executing run #4 ... ]
[ perf stat: executing run #5 ... ]
[ perf stat: executing run #6 ... ]
[ perf stat: executing run #7 ... ]
[ perf stat: executing run #8 ... ]
[ perf stat: executing run #9 ... ]
[ perf stat: executing run #10 ... ]

 Performance counter stats for 'sleep 1' (10 runs):

            0.9500 +- 0.0512 seconds time elapsed  ( +-  5.39% )

0.01user 0.02system 0:09.53elapsed 0%CPU (0avgtext+0avgdata 18940maxresident)k
29944inputs+0outputs (0major+2629minor)pagefaults 0swaps
```

Terminate the repeated run and give a reasonable exit value:
```
$ perf stat -v --null --repeat 10 sleep 1
Control descriptor is not initialized
[ perf stat: executing run #1 ... ]
[ perf stat: executing run #2 ... ]
[ perf stat: executing run #3 ... ]
^Csleep: Interrupt

 Performance counter stats for 'sleep 1' (10 runs):

             0.680 +- 0.321 seconds time elapsed  ( +- 47.16% )

Command exited with non-zero status 130
0.00user 0.01system 0:02.05elapsed 0%CPU (0avgtext+0avgdata 70688maxresident)k
0inputs+0outputs (0major+5002minor)pagefaults 0swaps
```

Note, this also changes the exit value for non-repeat runs when
interrupted by a signal.

Reported-by: Ingo Molnar <[email protected]>
Closes: https://lore.kernel.org/lkml/[email protected]/
Signed-off-by: Ian Rogers <[email protected]>
Tested-by: Thomas Richter <[email protected]>
Signed-off-by: Namhyung Kim <[email protected]>
github-actions bot pushed a commit that referenced this pull request Dec 6, 2025
The one_time_gc field in struct victim_sel_policy is conditionally
initialized but unconditionally read, leading to undefined behavior
that triggers UBSAN warnings.

In f2fs_get_victim() at fs/f2fs/gc.c:774, the victim_sel_policy
structure is declared without initialization:

    struct victim_sel_policy p;

The field p.one_time_gc is only assigned when the 'one_time' parameter
is true (line 789):

    if (one_time) {
        p.one_time_gc = one_time;
        ...
    }

However, this field is unconditionally read in subsequent get_gc_cost()
at line 395:

    if (p->one_time_gc && (valid_thresh_ratio < 100) && ...)

When one_time is false, p.one_time_gc contains uninitialized stack
memory. Hence p.one_time_gc is an invalid bool value.

UBSAN detects this invalid bool value:

    UBSAN: invalid-load in fs/f2fs/gc.c:395:7
    load of value 77 is not a valid value for type '_Bool'
    CPU: 3 UID: 0 PID: 1297 Comm: f2fs_gc-252:16 Not tainted 6.18.0-rc3
    #5 PREEMPT(voluntary)
    Hardware name: OpenStack Foundation OpenStack Nova,
    BIOS 1.13.0-1ubuntu1.1 04/01/2014
    Call Trace:
     <TASK>
     dump_stack_lvl+0x70/0x90
     dump_stack+0x14/0x20
     __ubsan_handle_load_invalid_value+0xb3/0xf0
     ? dl_server_update+0x2e/0x40
     ? update_curr+0x147/0x170
     f2fs_get_victim.cold+0x66/0x134 [f2fs]
     ? sched_balance_newidle+0x2ca/0x470
     ? finish_task_switch.isra.0+0x8d/0x2a0
     f2fs_gc+0x2ba/0x8e0 [f2fs]
     ? _raw_spin_unlock_irqrestore+0x12/0x40
     ? __timer_delete_sync+0x80/0xe0
     ? timer_delete_sync+0x14/0x20
     ? schedule_timeout+0x82/0x100
     gc_thread_func+0x38b/0x860 [f2fs]
     ? gc_thread_func+0x38b/0x860 [f2fs]
     ? __pfx_autoremove_wake_function+0x10/0x10
     kthread+0x10b/0x220
     ? __pfx_gc_thread_func+0x10/0x10 [f2fs]
     ? _raw_spin_unlock_irq+0x12/0x40
     ? __pfx_kthread+0x10/0x10
     ret_from_fork+0x11a/0x160
     ? __pfx_kthread+0x10/0x10
     ret_from_fork_asm+0x1a/0x30
     </TASK>

This issue is reliably reproducible with the following steps on a
100GB SSD /dev/vdb:

    mkfs.f2fs -f /dev/vdb
    mount /dev/vdb /mnt/f2fs_test
    fio --name=gc --directory=/mnt/f2fs_test --rw=randwrite \
        --bs=4k --size=8G --numjobs=12 --fsync=4 --runtime=10 \
        --time_based
    echo 1 > /sys/fs/f2fs/vdb/gc_urgent

The uninitialized value causes incorrect GC victim selection, leading
to unpredictable garbage collection behavior.

Fix by zero-initializing the entire victim_sel_policy structure to
ensure all fields have defined values.

Fixes: e791d00 ("f2fs: add valid block ratio not to do excessive GC for one time GC")
Cc: [email protected]
Signed-off-by: Xiaole He <[email protected]>
Reviewed-by: Chao Yu <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>
github-actions bot pushed a commit that referenced this pull request Dec 19, 2025
Patch series "kallsyms: Prevent invalid access when showing module
buildid", v3.

We have seen nested crashes in __sprint_symbol(), see below.  They seem to
be caused by an invalid pointer to "buildid".  This patchset cleans up
kallsyms code related to module buildid and fixes this invalid access when
printing backtraces.

I made an audit of __sprint_symbol() and found several situations
when the buildid might be wrong:

  + bpf_address_lookup() does not set @modbuildid

  + ftrace_mod_address_lookup() does not set @modbuildid

  + __sprint_symbol() does not take rcu_read_lock and
    the related struct module might get removed before
    mod->build_id is printed.

This patchset solves these problems:

  + 1st, 2nd patches are preparatory
  + 3rd, 4th, 6th patches fix the above problems
  + 5th patch cleans up a suspicious initialization code.

This is the backtrace, we have seen. But it is not really important.
The problems fixed by the patchset are obvious:

  crash64> bt [62/2029]
  PID: 136151 TASK: ffff9f6c981d4000 CPU: 367 COMMAND: "btrfs"
  #0 [ffffbdb687635c28] machine_kexec at ffffffffb4c845b3
  #1 [ffffbdb687635c80] __crash_kexec at ffffffffb4d86a6a
  #2 [ffffbdb687635d08] hex_string at ffffffffb51b3b61
  #3 [ffffbdb687635d40] crash_kexec at ffffffffb4d87964
  #4 [ffffbdb687635d50] oops_end at ffffffffb4c41fc8
  #5 [ffffbdb687635d70] do_trap at ffffffffb4c3e49a
  #6 [ffffbdb687635db8] do_error_trap at ffffffffb4c3e6a4
  #7 [ffffbdb687635df8] exc_stack_segment at ffffffffb5666b33
  #8 [ffffbdb687635e20] asm_exc_stack_segment at ffffffffb5800cf9
  ...


This patch (of 7)

The function kallsyms_lookup_buildid() initializes the given @namebuf by
clearing the first and the last byte.  It is not clear why.

The 1st byte makes sense because some callers ignore the return code and
expect that the buffer contains a valid string, for example:

  - function_stat_show()
    - kallsyms_lookup()
      - kallsyms_lookup_buildid()

The initialization of the last byte does not make much sense because it
can later be overwritten.  Fortunately, it seems that all called functions
behave correctly:

  -  kallsyms_expand_symbol() explicitly adds the trailing '\0'
     at the end of the function.

  - All *__address_lookup() functions either use the safe strscpy()
    or they do not touch the buffer at all.

Document the reason for clearing the first byte.  And remove the useless
initialization of the last byte.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
Reviewed-by: Aaron Tomlin <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Daniel Borkman <[email protected]>
Cc: John Fastabend <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Luis Chamberalin <[email protected]>
Cc: Marc Rutland <[email protected]>
Cc: "Masami Hiramatsu (Google)" <[email protected]>
Cc: Petr Pavlu <[email protected]>
Cc: Sami Tolvanen <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Daniel Gomez <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
github-actions bot pushed a commit that referenced this pull request Dec 20, 2025
Fix a loop scenario of ethx:egress->ethx:egress

Example setup to reproduce:
tc qdisc add dev ethx root handle 1: drr
tc filter add dev ethx parent 1: protocol ip prio 1 matchall \
         action mirred egress redirect dev ethx

Now ping out of ethx and you get a deadlock:

[  116.892898][  T307] ============================================
[  116.893182][  T307] WARNING: possible recursive locking detected
[  116.893418][  T307] 6.18.0-rc6-01205-ge05021a829b8-dirty #204 Not tainted
[  116.893682][  T307] --------------------------------------------
[  116.893926][  T307] ping/307 is trying to acquire lock:
[  116.894133][  T307] ffff88800c122908 (&sch->root_lock_key){+...}-{3:3}, at: __dev_queue_xmit+0x2210/0x3b50
[  116.894517][  T307]
[  116.894517][  T307] but task is already holding lock:
[  116.894836][  T307] ffff88800c122908 (&sch->root_lock_key){+...}-{3:3}, at: __dev_queue_xmit+0x2210/0x3b50
[  116.895252][  T307]
[  116.895252][  T307] other info that might help us debug this:
[  116.895608][  T307]  Possible unsafe locking scenario:
[  116.895608][  T307]
[  116.895901][  T307]        CPU0
[  116.896057][  T307]        ----
[  116.896200][  T307]   lock(&sch->root_lock_key);
[  116.896392][  T307]   lock(&sch->root_lock_key);
[  116.896605][  T307]
[  116.896605][  T307]  *** DEADLOCK ***
[  116.896605][  T307]
[  116.896864][  T307]  May be due to missing lock nesting notation
[  116.896864][  T307]
[  116.897123][  T307] 6 locks held by ping/307:
[  116.897302][  T307]  #0: ffff88800b4b0250 (sk_lock-AF_INET){+.+.}-{0:0}, at: raw_sendmsg+0xb20/0x2cf0
[  116.897808][  T307]  #1: ffffffff88c839c0 (rcu_read_lock){....}-{1:3}, at: ip_output+0xa9/0x600
[  116.898138][  T307]  #2: ffffffff88c839c0 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0x2c6/0x1ee0
[  116.898459][  T307]  #3: ffffffff88c83960 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x200/0x3b50
[  116.898782][  T307]  #4: ffff88800c122908 (&sch->root_lock_key){+...}-{3:3}, at: __dev_queue_xmit+0x2210/0x3b50
[  116.899132][  T307]  #5: ffffffff88c83960 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x200/0x3b50
[  116.899442][  T307]
[  116.899442][  T307] stack backtrace:
[  116.899667][  T307] CPU: 2 UID: 0 PID: 307 Comm: ping Not tainted 6.18.0-rc6-01205-ge05021a829b8-dirty #204 PREEMPT(voluntary)
[  116.899672][  T307] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  116.899675][  T307] Call Trace:
[  116.899678][  T307]  <TASK>
[  116.899680][  T307]  dump_stack_lvl+0x6f/0xb0
[  116.899688][  T307]  print_deadlock_bug.cold+0xc0/0xdc
[  116.899695][  T307]  __lock_acquire+0x11f7/0x1be0
[  116.899704][  T307]  lock_acquire+0x162/0x300
[  116.899707][  T307]  ? __dev_queue_xmit+0x2210/0x3b50
[  116.899713][  T307]  ? srso_alias_return_thunk+0x5/0xfbef5
[  116.899717][  T307]  ? stack_trace_save+0x93/0xd0
[  116.899723][  T307]  _raw_spin_lock+0x30/0x40
[  116.899728][  T307]  ? __dev_queue_xmit+0x2210/0x3b50
[  116.899731][  T307]  __dev_queue_xmit+0x2210/0x3b50

Fixes: 178ca30 ("Revert "net/sched: Fix mirred deadlock on device recursion"")
Tested-by: Victor Nogueira <[email protected]>
Signed-off-by: Jamal Hadi Salim <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Projects

None yet

Development

Successfully merging this pull request may close these issues.

2 participants