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@mpe mpe commented May 20, 2015

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mpe and others added 2 commits May 18, 2015 16:48
The only little endian configuration we support is ppc64le, all other
configurations are big endian.

So we should only offer a choice of endian if we're building for 64-bit
Book3S, ie. PPC_BOOK3S_64.

Signed-off-by: Michael Ellerman <[email protected]>
The commit 8170a83 ("powerpc: Wireup the kcmp syscall to sys_ni") has
disabled the kcmp syscall for powerpc.  This has been done due to the use
of unsigned long parameters which may require a dedicated wrapper to handle
32bit process on top of 64bit kernel.  However in the kcmp() case, the 2
unsigned long parameters are currently only used to carry file descriptors
from user space to the kernel.  Since such a parameter is passed through
register, and file descriptor doesn't need to get extended, there is,
today, no need for a wrapper.

In the case there will be a need to pass address in or out of this system
call, then a wrapper could be required, it will then be to care of it.

As today this is not the case, it is safe to enable kcmp() on powerpc.

Tested (by Laurent) on 64-bit, 32-bit, and 32-bit userspace on 64-bit
kernel using tools/testing/selftests/kcmp [mpe].

Signed-off-by: Laurent Dufour <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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mpe commented May 20, 2015

Buildbot: OK

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mpe commented May 20, 2015

Kisskb: OK

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mpe commented May 22, 2015

Selftests: OK

mpe added a commit that referenced this pull request May 22, 2015
@mpe mpe merged commit 439b40c into next May 22, 2015
mpe pushed a commit that referenced this pull request Sep 3, 2015
Peter reported the following potential crash which I was able to
reproduce with his test program,

[  148.765788] ------------[ cut here ]------------
[  148.765796] WARNING: CPU: 34 PID: 2840 at kernel/smp.c:417 smp_call_function_many+0xb6/0x260()
[  148.765797] Modules linked in:
[  148.765800] CPU: 34 PID: 2840 Comm: perf Not tainted 4.2.0-rc1+ #4
[  148.765803]  ffffffff81cdc398 ffff88085f105950 ffffffff818bdfd5 0000000000000007
[  148.765805]  0000000000000000 ffff88085f105990 ffffffff810e413a 0000000000000000
[  148.765807]  ffffffff82301080 0000000000000022 ffffffff8107f640 ffffffff8107f640
[  148.765809] Call Trace:
[  148.765810]  <NMI>  [<ffffffff818bdfd5>] dump_stack+0x45/0x57
[  148.765818]  [<ffffffff810e413a>] warn_slowpath_common+0x8a/0xc0
[  148.765822]  [<ffffffff8107f640>] ? intel_cqm_stable+0x60/0x60
[  148.765824]  [<ffffffff8107f640>] ? intel_cqm_stable+0x60/0x60
[  148.765825]  [<ffffffff810e422a>] warn_slowpath_null+0x1a/0x20
[  148.765827]  [<ffffffff811613f6>] smp_call_function_many+0xb6/0x260
[  148.765829]  [<ffffffff8107f640>] ? intel_cqm_stable+0x60/0x60
[  148.765831]  [<ffffffff81161748>] on_each_cpu_mask+0x28/0x60
[  148.765832]  [<ffffffff8107f6ef>] intel_cqm_event_count+0x7f/0xe0
[  148.765836]  [<ffffffff811cdd35>] perf_output_read+0x2a5/0x400
[  148.765839]  [<ffffffff811d2e5a>] perf_output_sample+0x31a/0x590
[  148.765840]  [<ffffffff811d333d>] ? perf_prepare_sample+0x26d/0x380
[  148.765841]  [<ffffffff811d3497>] perf_event_output+0x47/0x60
[  148.765843]  [<ffffffff811d36c5>] __perf_event_overflow+0x215/0x240
[  148.765844]  [<ffffffff811d4124>] perf_event_overflow+0x14/0x20
[  148.765847]  [<ffffffff8107e7f4>] intel_pmu_handle_irq+0x1d4/0x440
[  148.765849]  [<ffffffff811d07a6>] ? __perf_event_task_sched_in+0x36/0xa0
[  148.765853]  [<ffffffff81219bad>] ? vunmap_page_range+0x19d/0x2f0
[  148.765854]  [<ffffffff81219d11>] ? unmap_kernel_range_noflush+0x11/0x20
[  148.765859]  [<ffffffff814ce6fe>] ? ghes_copy_tofrom_phys+0x11e/0x2a0
[  148.765863]  [<ffffffff8109e5db>] ? native_apic_msr_write+0x2b/0x30
[  148.765865]  [<ffffffff8109e44d>] ? x2apic_send_IPI_self+0x1d/0x20
[  148.765869]  [<ffffffff81065135>] ? arch_irq_work_raise+0x35/0x40
[  148.765872]  [<ffffffff811c8d86>] ? irq_work_queue+0x66/0x80
[  148.765875]  [<ffffffff81075306>] perf_event_nmi_handler+0x26/0x40
[  148.765877]  [<ffffffff81063ed9>] nmi_handle+0x79/0x100
[  148.765879]  [<ffffffff81064422>] default_do_nmi+0x42/0x100
[  148.765880]  [<ffffffff81064563>] do_nmi+0x83/0xb0
[  148.765884]  [<ffffffff818c7c0f>] end_repeat_nmi+0x1e/0x2e
[  148.765886]  [<ffffffff811d07a6>] ? __perf_event_task_sched_in+0x36/0xa0
[  148.765888]  [<ffffffff811d07a6>] ? __perf_event_task_sched_in+0x36/0xa0
[  148.765890]  [<ffffffff811d07a6>] ? __perf_event_task_sched_in+0x36/0xa0
[  148.765891]  <<EOE>>  [<ffffffff8110ab66>] finish_task_switch+0x156/0x210
[  148.765898]  [<ffffffff818c1671>] __schedule+0x341/0x920
[  148.765899]  [<ffffffff818c1c87>] schedule+0x37/0x80
[  148.765903]  [<ffffffff810ae1af>] ? do_page_fault+0x2f/0x80
[  148.765905]  [<ffffffff818c1f4a>] schedule_user+0x1a/0x50
[  148.765907]  [<ffffffff818c666c>] retint_careful+0x14/0x32
[  148.765908] ---[ end trace e33ff2be78e14901 ]---

The CQM task events are not safe to be called from within interrupt
context because they require performing an IPI to read the counter value
on all sockets. And performing IPIs from within IRQ context is a
"no-no".

Make do with the last read counter value currently event in
event->count when we're invoked in this context.

Reported-by: Peter Zijlstra <[email protected]>
Signed-off-by: Matt Fleming <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vikas Shivappa <[email protected]>
Cc: Kanaka Juvva <[email protected]>
Cc: Will Auld <[email protected]>
Cc: <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
mpe pushed a commit that referenced this pull request Sep 3, 2015
This patch adds the missing update of the transfer data width in
at_xdmac_prep_slave_sg().

Indeed, for each item in the scatter-gather list, we check whether the
transfer length is aligned with the data width provided by
dmaengine_slave_config(). If so, we directly use this data width for the
current part of the transfer we are preparing. Otherwise, the data width
is reduced to 8 bits (1 byte). Of course, the actual number of register
accesses must also be updated to match the new data width.

So one chunk was missing in the original patch (see Fixes tag below): the
number of register accesses was correctly set to (len >> fixed_dwidth) in
mbr_ubc but the real data width was not updated in mbr_cfg. Since mbr_cfg
may change for each part of the scatter-gather transfer this also explains
why the original patch used the Descriptor View 2 instead of the
Descriptor View 1.

Let's take the example of a DMA transfer to write 8bit data into an Atmel
USART with FIFOs. When FIFOs are enabled in the USART, its Transmit
Holding Register (THR) works in multidata mode, that is to say that up to
4 8bit data can be written into the THR in a single 32bit access and it is
still possible to write only one data with a 8bit access. To take
advantage of this new feature, the DMA driver was modified to allow
multiple dwidths when doing slave transfers.
For instance, when the total length is 22 bytes, the USART driver splits
the transfer into 2 parts:

First part: 20 bytes transferred through 5 32bit writes into THR
Second part: 2 bytes transferred though 2 8bit writes into THR

For the second part, the data width was first set to 4_BYTES by the USART
driver thanks to dmaengine_slave_config() then at_xdmac_prep_slave_sg()
reduces this data width to 1_BYTE because the 2 byte length is not aligned
with the original 4_BYTES data width. Since the data width is modified,
the actual number of writes into THR must be set accordingly.

Signed-off-by: Cyrille Pitchen <[email protected]>
Fixes: 6d3a7d9 ("dmaengine: at_xdmac: allow muliple dwidths when doing slave transfers")
Cc: [email protected] #4.0 and later
Acked-by: Nicolas Ferre <[email protected]>
Acked-by: Ludovic Desroches <[email protected]>
Signed-off-by: Vinod Koul <[email protected]>
mpe pushed a commit that referenced this pull request Sep 3, 2015
Nikolay has reported a hang when a memcg reclaim got stuck with the
following backtrace:

PID: 18308  TASK: ffff883d7c9b0a30  CPU: 1   COMMAND: "rsync"
  #0 __schedule at ffffffff815ab152
  #1 schedule at ffffffff815ab76e
  #2 schedule_timeout at ffffffff815ae5e5
  #3 io_schedule_timeout at ffffffff815aad6a
  #4 bit_wait_io at ffffffff815abfc6
  #5 __wait_on_bit at ffffffff815abda5
  #6 wait_on_page_bit at ffffffff8111fd4f
  #7 shrink_page_list at ffffffff81135445
  #8 shrink_inactive_list at ffffffff81135845
  #9 shrink_lruvec at ffffffff81135ead
 #10 shrink_zone at ffffffff811360c3
 torvalds#11 shrink_zones at ffffffff81136eff
 torvalds#12 do_try_to_free_pages at ffffffff8113712f
 torvalds#13 try_to_free_mem_cgroup_pages at ffffffff811372be
 torvalds#14 try_charge at ffffffff81189423
 torvalds#15 mem_cgroup_try_charge at ffffffff8118c6f5
 torvalds#16 __add_to_page_cache_locked at ffffffff8112137d
 torvalds#17 add_to_page_cache_lru at ffffffff81121618
 torvalds#18 pagecache_get_page at ffffffff8112170b
 torvalds#19 grow_dev_page at ffffffff811c8297
 torvalds#20 __getblk_slow at ffffffff811c91d6
 torvalds#21 __getblk_gfp at ffffffff811c92c1
 torvalds#22 ext4_ext_grow_indepth at ffffffff8124565c
 torvalds#23 ext4_ext_create_new_leaf at ffffffff81246ca8
 torvalds#24 ext4_ext_insert_extent at ffffffff81246f09
 torvalds#25 ext4_ext_map_blocks at ffffffff8124a848
 torvalds#26 ext4_map_blocks at ffffffff8121a5b7
 torvalds#27 mpage_map_one_extent at ffffffff8121b1fa
 torvalds#28 mpage_map_and_submit_extent at ffffffff8121f07b
 torvalds#29 ext4_writepages at ffffffff8121f6d5
 torvalds#30 do_writepages at ffffffff8112c490
 torvalds#31 __filemap_fdatawrite_range at ffffffff81120199
 torvalds#32 filemap_flush at ffffffff8112041c
 torvalds#33 ext4_alloc_da_blocks at ffffffff81219da1
 torvalds#34 ext4_rename at ffffffff81229b91
 torvalds#35 ext4_rename2 at ffffffff81229e32
 torvalds#36 vfs_rename at ffffffff811a08a5
 torvalds#37 SYSC_renameat2 at ffffffff811a3ffc
 torvalds#38 sys_renameat2 at ffffffff811a408e
 torvalds#39 sys_rename at ffffffff8119e51e
 torvalds#40 system_call_fastpath at ffffffff815afa89

Dave Chinner has properly pointed out that this is a deadlock in the
reclaim code because ext4 doesn't submit pages which are marked by
PG_writeback right away.

The heuristic was introduced by commit e62e384 ("memcg: prevent OOM
with too many dirty pages") and it was applied only when may_enter_fs
was specified.  The code has been changed by c3b94f4 ("memcg:
further prevent OOM with too many dirty pages") which has removed the
__GFP_FS restriction with a reasoning that we do not get into the fs
code.  But this is not sufficient apparently because the fs doesn't
necessarily submit pages marked PG_writeback for IO right away.

ext4_bio_write_page calls io_submit_add_bh but that doesn't necessarily
submit the bio.  Instead it tries to map more pages into the bio and
mpage_map_one_extent might trigger memcg charge which might end up
waiting on a page which is marked PG_writeback but hasn't been submitted
yet so we would end up waiting for something that never finishes.

Fix this issue by replacing __GFP_IO by may_enter_fs check (for case 2)
before we go to wait on the writeback.  The page fault path, which is
the only path that triggers memcg oom killer since 3.12, shouldn't
require GFP_NOFS and so we shouldn't reintroduce the premature OOM
killer issue which was originally addressed by the heuristic.

As per David Chinner the xfs is doing similar thing since 2.6.15 already
so ext4 is not the only affected filesystem.  Moreover he notes:

: For example: IO completion might require unwritten extent conversion
: which executes filesystem transactions and GFP_NOFS allocations. The
: writeback flag on the pages can not be cleared until unwritten
: extent conversion completes. Hence memory reclaim cannot wait on
: page writeback to complete in GFP_NOFS context because it is not
: safe to do so, memcg reclaim or otherwise.

Cc: [email protected] # 3.9+
[[email protected]: corrected the control flow]
Fixes: c3b94f4 ("memcg: further prevent OOM with too many dirty pages")
Reported-by: Nikolay Borisov <[email protected]>
Signed-off-by: Michal Hocko <[email protected]>
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
mpe pushed a commit that referenced this pull request Sep 3, 2015
It turns out that a PV domU also requires the "Xen PV" APIC
driver. Otherwise, the flat driver is used and we get stuck in busy
loops that never exit, such as in this stack trace:

(gdb) target remote localhost:9999
Remote debugging using localhost:9999
__xapic_wait_icr_idle () at ./arch/x86/include/asm/ipi.h:56
56              while (native_apic_mem_read(APIC_ICR) & APIC_ICR_BUSY)
(gdb) bt
 #0  __xapic_wait_icr_idle () at ./arch/x86/include/asm/ipi.h:56
 #1  __default_send_IPI_shortcut (shortcut=<optimized out>,
dest=<optimized out>, vector=<optimized out>) at
./arch/x86/include/asm/ipi.h:75
 #2  apic_send_IPI_self (vector=246) at arch/x86/kernel/apic/probe_64.c:54
 #3  0xffffffff81011336 in arch_irq_work_raise () at
arch/x86/kernel/irq_work.c:47
 #4  0xffffffff8114990c in irq_work_queue (work=0xffff88000fc0e400) at
kernel/irq_work.c:100
 #5  0xffffffff8110c29d in wake_up_klogd () at kernel/printk/printk.c:2633
 #6  0xffffffff8110ca60 in vprintk_emit (facility=0, level=<optimized
out>, dict=0x0 <irq_stack_union>, dictlen=<optimized out>,
fmt=<optimized out>, args=<optimized out>)
    at kernel/printk/printk.c:1778
 #7  0xffffffff816010c8 in printk (fmt=<optimized out>) at
kernel/printk/printk.c:1868
 #8  0xffffffffc00013ea in ?? ()
 #9  0x0000000000000000 in ?? ()

Mailing-list-thread: https://lkml.org/lkml/2015/8/4/755
Signed-off-by: Jason A. Donenfeld <[email protected]>
Cc: <[email protected]>
Signed-off-by: David Vrabel <[email protected]>
mpe pushed a commit that referenced this pull request Sep 3, 2015
A recent change to the cpu_cooling code introduced a AB-BA deadlock
scenario between the cpufreq_policy_notifier_list rwsem and the
cooling_cpufreq_lock.  This is caused by cooling_cpufreq_lock being held
before the registration/removal of the notifier block (an operation
which takes the rwsem), and the notifier code itself which takes the
locks in the reverse order:

======================================================
[ INFO: possible circular locking dependency detected ]
3.18.0+ #1453 Not tainted
-------------------------------------------------------
rc.local/770 is trying to acquire lock:
 (cooling_cpufreq_lock){+.+.+.}, at: [<c04abfc4>] cpufreq_thermal_notifier+0x34/0xfc

but task is already holding lock:
 ((cpufreq_policy_notifier_list).rwsem){++++.+}, at: [<c0042f04>]  __blocking_notifier_call_chain+0x34/0x68

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 ((cpufreq_policy_notifier_list).rwsem){++++.+}:
       [<c06bc3b0>] down_write+0x44/0x9c
       [<c0043444>] blocking_notifier_chain_register+0x28/0xd8
       [<c04ad610>] cpufreq_register_notifier+0x68/0x90
       [<c04abe4c>] __cpufreq_cooling_register.part.1+0x120/0x180
       [<c04abf44>] __cpufreq_cooling_register+0x98/0xa4
       [<c04abf8c>] cpufreq_cooling_register+0x18/0x1c
       [<bf0046f8>] imx_thermal_probe+0x1c0/0x470 [imx_thermal]
       [<c037cef8>] platform_drv_probe+0x50/0xac
       [<c037b710>] driver_probe_device+0x114/0x234
       [<c037b8cc>] __driver_attach+0x9c/0xa0
       [<c0379d68>] bus_for_each_dev+0x5c/0x90
       [<c037b204>] driver_attach+0x24/0x28
       [<c037ae7c>] bus_add_driver+0xe0/0x1d8
       [<c037c0cc>] driver_register+0x80/0xfc
       [<c037cd80>] __platform_driver_register+0x50/0x64
       [<bf007018>] 0xbf007018
       [<c0008a5c>] do_one_initcall+0x88/0x1d8
       [<c0095da4>] load_module+0x1768/0x1ef8
       [<c0096614>] SyS_init_module+0xe0/0xf4
       [<c000ec00>] ret_fast_syscall+0x0/0x48

-> #0 (cooling_cpufreq_lock){+.+.+.}:
       [<c00619f8>] lock_acquire+0xb0/0x124
       [<c06ba3b4>] mutex_lock_nested+0x5c/0x3d8
       [<c04abfc4>] cpufreq_thermal_notifier+0x34/0xfc
       [<c0042bf4>] notifier_call_chain+0x4c/0x8c
       [<c0042f20>] __blocking_notifier_call_chain+0x50/0x68
       [<c0042f58>] blocking_notifier_call_chain+0x20/0x28
       [<c04ae62c>] cpufreq_set_policy+0x7c/0x1d0
       [<c04af3cc>] store_scaling_governor+0x74/0x9c
       [<c04ad418>] store+0x90/0xc0
       [<c0175384>] sysfs_kf_write+0x54/0x58
       [<c01746b4>] kernfs_fop_write+0xdc/0x190
       [<c010dcc0>] vfs_write+0xac/0x1b4
       [<c010dfec>] SyS_write+0x44/0x90
       [<c000ec00>] ret_fast_syscall+0x0/0x48

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock((cpufreq_policy_notifier_list).rwsem);
                               lock(cooling_cpufreq_lock);
                               lock((cpufreq_policy_notifier_list).rwsem);
  lock(cooling_cpufreq_lock);

 *** DEADLOCK ***

7 locks held by rc.local/770:
 #0:  (sb_writers#6){.+.+.+}, at: [<c010dda0>] vfs_write+0x18c/0x1b4
 #1:  (&of->mutex){+.+.+.}, at: [<c0174678>] kernfs_fop_write+0xa0/0x190
 #2:  (s_active#52){.+.+.+}, at: [<c0174680>] kernfs_fop_write+0xa8/0x190
 #3:  (cpu_hotplug.lock){++++++}, at: [<c0026a60>] get_online_cpus+0x34/0x90
 #4:  (cpufreq_rwsem){.+.+.+}, at: [<c04ad3e0>] store+0x58/0xc0
 #5:  (&policy->rwsem){+.+.+.}, at: [<c04ad3f8>] store+0x70/0xc0
 #6:  ((cpufreq_policy_notifier_list).rwsem){++++.+}, at: [<c0042f04>] __blocking_notifier_call_chain+0x34/0x68

stack backtrace:
CPU: 0 PID: 770 Comm: rc.local Not tainted 3.18.0+ #1453
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
Backtrace:
[<c00121c8>] (dump_backtrace) from [<c0012360>] (show_stack+0x18/0x1c)
 r6:c0b85a80 r5:c0b75630 r4:00000000 r3:00000000
[<c0012348>] (show_stack) from [<c06b6c48>] (dump_stack+0x7c/0x98)
[<c06b6bcc>] (dump_stack) from [<c06b42a4>] (print_circular_bug+0x28c/0x2d8)
 r4:c0b85a80 r3:d0071d40
[<c06b4018>] (print_circular_bug) from [<c00613b0>] (__lock_acquire+0x1acc/0x1bb0)
 r10:c0b50660 r8:c09e6d80 r7:d0071d40 r6:c11d0f0c r5:00000007 r4:d0072240
[<c005f8e4>] (__lock_acquire) from [<c00619f8>] (lock_acquire+0xb0/0x124)
 r10:00000000 r9:c04abfc4 r8:00000000 r7:00000000 r6:00000000 r5:c0a06f0c
 r4:00000000
[<c0061948>] (lock_acquire) from [<c06ba3b4>] (mutex_lock_nested+0x5c/0x3d8)
 r10:ec853800 r9:c0a06ed4 r8:d0071d40 r7:c0a06ed4 r6:c11d0f0c r5:00000000
 r4:c04abfc4
[<c06ba358>] (mutex_lock_nested) from [<c04abfc4>] (cpufreq_thermal_notifier+0x34/0xfc)
 r10:ec853800 r9:ec85380c r8:d00d7d3c r7:c0a06ed4 r6:d00d7d3c r5:00000000
 r4:fffffffe
[<c04abf90>] (cpufreq_thermal_notifier) from [<c0042bf4>] (notifier_call_chain+0x4c/0x8c)
 r7:00000000 r6:00000000 r5:00000000 r4:fffffffe
[<c0042ba8>] (notifier_call_chain) from [<c0042f20>] (__blocking_notifier_call_chain+0x50/0x68)
 r8:c0a072a4 r7:00000000 r6:d00d7d3c r5:ffffffff r4:c0a06fc8 r3:ffffffff
[<c0042ed0>] (__blocking_notifier_call_chain) from [<c0042f58>] (blocking_notifier_call_chain+0x20/0x28)
 r7:ec98b540 r6:c13ebc80 r5:ed76e600 r4:d00d7d3c
[<c0042f38>] (blocking_notifier_call_chain) from [<c04ae62c>] (cpufreq_set_policy+0x7c/0x1d0)
[<c04ae5b0>] (cpufreq_set_policy) from [<c04af3cc>] (store_scaling_governor+0x74/0x9c)
 r7:ec98b540 r6:0000000c r5:ec98b540 r4:ed76e600
[<c04af358>] (store_scaling_governor) from [<c04ad418>] (store+0x90/0xc0)
 r6:0000000c r5:ed76e6d4 r4:ed76e600
[<c04ad388>] (store) from [<c0175384>] (sysfs_kf_write+0x54/0x58)
 r8:0000000c r7:d00d7f78 r6:ec98b540 r5:0000000c r4:ec853800 r3:0000000c
[<c0175330>] (sysfs_kf_write) from [<c01746b4>] (kernfs_fop_write+0xdc/0x190)
 r6:ec98b540 r5:00000000 r4:00000000 r3:c0175330
[<c01745d8>] (kernfs_fop_write) from [<c010dcc0>] (vfs_write+0xac/0x1b4)
 r10:0162aa70 r9:d00d6000 r8:0000000c r7:d00d7f78 r6:0162aa70 r5:0000000c
 r4:eccde500
[<c010dc14>] (vfs_write) from [<c010dfec>] (SyS_write+0x44/0x90)
 r10:0162aa70 r8:0000000c r7:eccde500 r6:eccde500 r5:00000000 r4:00000000
[<c010dfa8>] (SyS_write) from [<c000ec00>] (ret_fast_syscall+0x0/0x48)
 r10:00000000 r8:c000edc4 r7:00000004 r6:000216cc r5:0000000c r4:0162aa70

Solve this by moving to finer grained locking - use one mutex to protect
the cpufreq_dev_list as a whole, and a separate lock to ensure correct
ordering of cpufreq notifier registration and removal.

cooling_list_lock is taken within cooling_cpufreq_lock on
(un)registration to preserve the behavior of the code, i.e. to
atomically add/remove to the list and (un)register the notifier.

Fixes: 2dcd851 ("thermal: cpu_cooling: Update always cpufreq policy with
Reviewed-by: Viresh Kumar <[email protected]>
Signed-off-by: Russell King <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>
Signed-off-by: Eduardo Valentin <[email protected]>
mpe pushed a commit that referenced this pull request Sep 3, 2015
To please checkpatch and the tiresome reader, add the "atmel," prefix to the
USB udc compatible string.

Signed-off-by: Nicolas Ferre <[email protected]>
Cc: <[email protected]>  #4.0+
Signed-off-by: Kevin Hilman <[email protected]>
mpe pushed a commit that referenced this pull request Sep 3, 2015
at91sam9g45, at91sam9x5 and sama5 SoCs should not use
"atmel,at91sam9rl-udc" for their USB device compatible property since
this compatible is attached to a specific hardware bug fix.

Signed-off-by: Boris Brezillon <[email protected]>
Acked-by: Alexandre Belloni <[email protected]>
Tested-by: Bo Shen <[email protected]>
Acked-by: Nicolas Ferre <[email protected]>
Cc: <[email protected]>  #4.0+
Signed-off-by: Kevin Hilman <[email protected]>
mpe pushed a commit that referenced this pull request Sep 9, 2015
PID: 614    TASK: ffff882a739da580  CPU: 3   COMMAND: "ocfs2dc"
  #0 [ffff882ecc3759b0] machine_kexec at ffffffff8103b35d
  #1 [ffff882ecc375a20] crash_kexec at ffffffff810b95b5
  #2 [ffff882ecc375af0] oops_end at ffffffff815091d8
  #3 [ffff882ecc375b20] die at ffffffff8101868b
  #4 [ffff882ecc375b50] do_trap at ffffffff81508bb0
  #5 [ffff882ecc375ba0] do_invalid_op at ffffffff810165e5
  #6 [ffff882ecc375c40] invalid_op at ffffffff815116fb
     [exception RIP: ocfs2_ci_checkpointed+208]
     RIP: ffffffffa0a7e940  RSP: ffff882ecc375cf0  RFLAGS: 00010002
     RAX: 0000000000000001  RBX: 000000000000654b  RCX: ffff8812dc83f1f8
     RDX: 00000000000017d9  RSI: ffff8812dc83f1f8  RDI: ffffffffa0b2c318
     RBP: ffff882ecc375d20   R8: ffff882ef6ecfa60   R9: ffff88301f272200
     R10: 0000000000000000  R11: 0000000000000000  R12: ffffffffffffffff
     R13: ffff8812dc83f4f0  R14: 0000000000000000  R15: ffff8812dc83f1f8
     ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
  #7 [ffff882ecc375d28] ocfs2_check_meta_downconvert at ffffffffa0a7edbd [ocfs2]
  #8 [ffff882ecc375d38] ocfs2_unblock_lock at ffffffffa0a84af8 [ocfs2]
  #9 [ffff882ecc375dc8] ocfs2_process_blocked_lock at ffffffffa0a85285 [ocfs2]
#10 [ffff882ecc375e18] ocfs2_downconvert_thread_do_work at ffffffffa0a85445 [ocfs2]
torvalds#11 [ffff882ecc375e68] ocfs2_downconvert_thread at ffffffffa0a854de [ocfs2]
torvalds#12 [ffff882ecc375ee8] kthread at ffffffff81090da7
torvalds#13 [ffff882ecc375f48] kernel_thread_helper at ffffffff81511884
assert is tripped because the tran is not checkpointed and the lock level is PR.

Some time ago, chmod command had been executed. As result, the following call
chain left the inode cluster lock in PR state, latter on causing the assert.
system_call_fastpath
  -> my_chmod
   -> sys_chmod
    -> sys_fchmodat
     -> notify_change
      -> ocfs2_setattr
       -> posix_acl_chmod
        -> ocfs2_iop_set_acl
         -> ocfs2_set_acl
          -> ocfs2_acl_set_mode
Here is how.
1119 int ocfs2_setattr(struct dentry *dentry, struct iattr *attr)
1120 {
1247         ocfs2_inode_unlock(inode, 1); <<< WRONG thing to do.
..
1258         if (!status && attr->ia_valid & ATTR_MODE) {
1259                 status =  posix_acl_chmod(inode, inode->i_mode);

519 posix_acl_chmod(struct inode *inode, umode_t mode)
520 {
..
539         ret = inode->i_op->set_acl(inode, acl, ACL_TYPE_ACCESS);

287 int ocfs2_iop_set_acl(struct inode *inode, struct posix_acl *acl, ...
288 {
289         return ocfs2_set_acl(NULL, inode, NULL, type, acl, NULL, NULL);

224 int ocfs2_set_acl(handle_t *handle,
225                          struct inode *inode, ...
231 {
..
252                                 ret = ocfs2_acl_set_mode(inode, di_bh,
253                                                          handle, mode);

168 static int ocfs2_acl_set_mode(struct inode *inode, struct buffer_head ...
170 {
183         if (handle == NULL) {
                    >>> BUG: inode lock not held in ex at this point <<<
184                 handle = ocfs2_start_trans(OCFS2_SB(inode->i_sb),
185                                            OCFS2_INODE_UPDATE_CREDITS);

ocfs2_setattr.torvalds#1247 we unlock and at torvalds#1259 call posix_acl_chmod. When we reach
ocfs2_acl_set_mode.torvalds#181 and do trans, the inode cluster lock is not held in EX
mode (it should be). How this could have happended?

We are the lock master, were holding lock EX and have released it in
ocfs2_setattr.torvalds#1247.  Note that there are no holders of this lock at
this point.  Another node needs the lock in PR, and we downconvert from
EX to PR.  So the inode lock is PR when do the trans in
ocfs2_acl_set_mode.torvalds#184.  The trans stays in core (not flushed to disc).
Now another node want the lock in EX, downconvert thread gets kicked
(the one that tripped assert abovt), finds an unflushed trans but the
lock is not EX (it is PR).  If the lock was at EX, it would have flushed
the trans ocfs2_ci_checkpointed -> ocfs2_start_checkpoint before
downconverting (to NULL) for the request.

ocfs2_setattr must not drop inode lock ex in this code path.  If it
does, takes it again before the trans, say in ocfs2_set_acl, another
cluster node can get in between, execute another setattr, overwriting
the one in progress on this node, resulting in a mode acl size combo
that is a mix of the two.

Orabug: 20189959
Signed-off-by: Tariq Saeed <[email protected]>
Reviewed-by: Mark Fasheh <[email protected]>
Cc: Joel Becker <[email protected]>
Cc: Joseph Qi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
@mpe mpe deleted the review/misc branch February 22, 2016 09:53
mpe pushed a commit that referenced this pull request Feb 7, 2019
This patch makes sure the flow label in the IPv6 header
forged in ipv6_local_error() is initialized.

BUG: KMSAN: kernel-infoleak in _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32
CPU: 1 PID: 24675 Comm: syz-executor1 Not tainted 4.20.0-rc7+ #4
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+0x173/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x12e/0x2a0 mm/kmsan/kmsan.c:613
 kmsan_internal_check_memory+0x455/0xb00 mm/kmsan/kmsan.c:675
 kmsan_copy_to_user+0xab/0xc0 mm/kmsan/kmsan_hooks.c:601
 _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32
 copy_to_user include/linux/uaccess.h:177 [inline]
 move_addr_to_user+0x2e9/0x4f0 net/socket.c:227
 ___sys_recvmsg+0x5d7/0x1140 net/socket.c:2284
 __sys_recvmsg net/socket.c:2327 [inline]
 __do_sys_recvmsg net/socket.c:2337 [inline]
 __se_sys_recvmsg+0x2fa/0x450 net/socket.c:2334
 __x64_sys_recvmsg+0x4a/0x70 net/socket.c:2334
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x457ec9
Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f8750c06c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457ec9
RDX: 0000000000002000 RSI: 0000000020000400 RDI: 0000000000000005
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8750c076d4
R13: 00000000004c4a60 R14: 00000000004d8140 R15: 00000000ffffffff

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:204 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:219 [inline]
 kmsan_internal_chain_origin+0x134/0x230 mm/kmsan/kmsan.c:439
 __msan_chain_origin+0x70/0xe0 mm/kmsan/kmsan_instr.c:200
 ipv6_recv_error+0x1e3f/0x1eb0 net/ipv6/datagram.c:475
 udpv6_recvmsg+0x398/0x2ab0 net/ipv6/udp.c:335
 inet_recvmsg+0x4fb/0x600 net/ipv4/af_inet.c:830
 sock_recvmsg_nosec net/socket.c:794 [inline]
 sock_recvmsg+0x1d1/0x230 net/socket.c:801
 ___sys_recvmsg+0x4d5/0x1140 net/socket.c:2278
 __sys_recvmsg net/socket.c:2327 [inline]
 __do_sys_recvmsg net/socket.c:2337 [inline]
 __se_sys_recvmsg+0x2fa/0x450 net/socket.c:2334
 __x64_sys_recvmsg+0x4a/0x70 net/socket.c:2334
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:204 [inline]
 kmsan_internal_poison_shadow+0x92/0x150 mm/kmsan/kmsan.c:158
 kmsan_kmalloc+0xa6/0x130 mm/kmsan/kmsan_hooks.c:176
 kmsan_slab_alloc+0xe/0x10 mm/kmsan/kmsan_hooks.c:185
 slab_post_alloc_hook mm/slab.h:446 [inline]
 slab_alloc_node mm/slub.c:2759 [inline]
 __kmalloc_node_track_caller+0xe18/0x1030 mm/slub.c:4383
 __kmalloc_reserve net/core/skbuff.c:137 [inline]
 __alloc_skb+0x309/0xa20 net/core/skbuff.c:205
 alloc_skb include/linux/skbuff.h:998 [inline]
 ipv6_local_error+0x1a7/0x9e0 net/ipv6/datagram.c:334
 __ip6_append_data+0x129f/0x4fd0 net/ipv6/ip6_output.c:1311
 ip6_make_skb+0x6cc/0xcf0 net/ipv6/ip6_output.c:1775
 udpv6_sendmsg+0x3f8e/0x45d0 net/ipv6/udp.c:1384
 inet_sendmsg+0x54a/0x720 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 __sys_sendto+0x8c4/0xac0 net/socket.c:1788
 __do_sys_sendto net/socket.c:1800 [inline]
 __se_sys_sendto+0x107/0x130 net/socket.c:1796
 __x64_sys_sendto+0x6e/0x90 net/socket.c:1796
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7

Bytes 4-7 of 28 are uninitialized
Memory access of size 28 starts at ffff8881937bfce0
Data copied to user address 0000000020000000

Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: syzbot <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
mpe pushed a commit that referenced this pull request Feb 7, 2019
When SCSI-MQ is enabled, in some case system would present
nr_possible_cpus() which is greater than requested vectors by the
driver. This results into driver being able to get larger number of MSI-X
vectors than actual online CPUs.  Driver then uses
pci_alloc_irq_vectors_affinity() to assign 1:1 mapping and affinity for
each MSI-x vector to CPUs. When the command is submitted using MSI-x
vector, assigned to offline CPU, it results in an ABTS and system
hang. This hang is result of a driver not being able to process interrupt
on a vector assigned to an Off-line CPUs

This patch fixes this issue by setting irq_offset value for the
blk_mq_pci_map_queues() to use only those CPUs which has CPU mask affinity
assigned and are online. By using the irq_offset value, driver will allow
online cpumask to decide which vectors are used in blk_mq_pci_map_queues().

Fixes: 5601236 ("scsi: qla2xxx: Add Block Multi Queue functionality.")
Cc: <[email protected]> #4.19
Signed-off-by: Ming Lei <[email protected]>
Reviewed-by: Himanshu Madhani <[email protected]>
Tested-by: Himanshu Madhani <[email protected]>
Reviewed-by: Ewan D. Milne <[email protected]>
Signed-off-by: Himanshu Madhani <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
mpe pushed a commit that referenced this pull request Feb 7, 2019
Song Liu reported crash in 'perf record':

  > #0  0x0000000000500055 in ordered_events(float, long double,...)(...) ()
  > #1  0x0000000000500196 in ordered_events.reinit ()
  > #2  0x00000000004fe413 in perf_session.process_events ()
  > #3  0x0000000000440431 in cmd_record ()
  > #4  0x00000000004a439f in run_builtin ()
  > #5  0x000000000042b3e5 in main ()"

This can happen when we get out of buffers during event processing.

The subsequent ordered_events__free() call assumes oe->buffer != NULL
and crashes. Add a check to prevent that.

Reported-by: Song Liu <[email protected]>
Signed-off-by: Jiri Olsa <[email protected]>
Reviewed-by: Song Liu <[email protected]>
Tested-by: Song Liu <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Fixes: d5ceb62 ("perf ordered_events: Add 'struct ordered_events_buffer' layer")
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
mpe pushed a commit that referenced this pull request Feb 7, 2019
In setup_arch_memory we reserve the memory area wherein the kernel
is located. Current implementation may reserve more memory than
it actually required in case of CONFIG_LINUX_LINK_BASE is not
equal to CONFIG_LINUX_RAM_BASE. This happens because we calculate
start of the reserved region relatively to the CONFIG_LINUX_RAM_BASE
and end of the region relatively to the CONFIG_LINUX_RAM_BASE.

For example in case of HSDK board we wasted 256MiB of physical memory:
------------------->8------------------------------
Memory: 770416K/1048576K available (5496K kernel code,
    240K rwdata, 1064K rodata, 2200K init, 275K bss,
    278160K reserved, 0K cma-reserved)
------------------->8------------------------------

Fix that.

Fixes: 9ed6878 ("ARC: mm: Decouple RAM base address from kernel link addr")
Cc: [email protected]	#4.14+
Signed-off-by: Eugeniy Paltsev <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>
mpe pushed a commit that referenced this pull request Feb 7, 2019
ARCv2 optimized memset uses PREFETCHW instruction for prefetching the
next cache line but doesn't ensure that the line is not past the end of
the buffer. PRETECHW changes the line ownership and marks it dirty,
which can cause issues in SMP config when next line was already owned by
other core. Fix the issue by avoiding the PREFETCHW

Some more details:

The current code has 3 logical loops (ignroing the unaligned part)
  (a) Big loop for doing aligned 64 bytes per iteration with PREALLOC
  (b) Loop for 32 x 2 bytes with PREFETCHW
  (c) any left over bytes

loop (a) was already eliding the last 64 bytes, so PREALLOC was
safe. The fix was removing PREFETCW from (b).

Another potential issue (applicable to configs with 32 or 128 byte L1
cache line) is that PREALLOC assumes 64 byte cache line and may not do
the right thing specially for 32b. While it would be easy to adapt,
there are no known configs with those lie sizes, so for now, just
compile out PREALLOC in such cases.

Signed-off-by: Eugeniy Paltsev <[email protected]>
Cc: [email protected] #4.4+
Signed-off-by: Vineet Gupta <[email protected]>
[vgupta: rewrote changelog, used asm .macro vs. "C" macro]
mpe pushed a commit that referenced this pull request Feb 7, 2019
Ido Schimmel says:

====================
mlxsw: Various fixes

This patchset contains small fixes in mlxsw and one fix in the bridge
driver.

Patches #1-#4 perform small adjustments in PCI and FID code following
recent tests that were performed on the Spectrum-2 ASIC.

Patch #5 fixes the bridge driver to mark FDB entries that were added by
user as such. Otherwise, these entries will be ignored by underlying
switch drivers.

Patch #6 fixes a long standing issue in mlxsw where the driver
incorrectly programmed static FDB entries as both static and sticky.

Patches #7-#8 add test cases for above mentioned bugs.

Please consider patches #1, #2 and #4 for stable.
====================

Signed-off-by: David S. Miller <[email protected]>
mpe pushed a commit that referenced this pull request Feb 7, 2019
When option CONFIG_KASAN is enabled toghether with ftrace, function
ftrace_graph_caller() gets in to a recursion, via functions
kasan_check_read() and kasan_check_write().

 Breakpoint 2, ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179
 179             mcount_get_pc             x0    //     function's pc
 (gdb) bt
 #0  ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179
 #1  0xffffff90101406c8 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:151
 #2  0xffffff90106fd084 in kasan_check_write (p=0xffffffc06c170878, size=4) at ../mm/kasan/common.c:105
 #3  0xffffff90104a2464 in atomic_add_return (v=<optimized out>, i=<optimized out>) at ./include/generated/atomic-instrumented.h:71
 #4  atomic_inc_return (v=<optimized out>) at ./include/generated/atomic-fallback.h:284
 #5  trace_graph_entry (trace=0xffffffc03f5ff380) at ../kernel/trace/trace_functions_graph.c:441
 #6  0xffffff9010481774 in trace_graph_entry_watchdog (trace=<optimized out>) at ../kernel/trace/trace_selftest.c:741
 #7  0xffffff90104a185c in function_graph_enter (ret=<optimized out>, func=<optimized out>, frame_pointer=18446743799894897728, retp=<optimized out>) at ../kernel/trace/trace_functions_graph.c:196
 #8  0xffffff9010140628 in prepare_ftrace_return (self_addr=18446743592948977792, parent=0xffffffc03f5ff418, frame_pointer=18446743799894897728) at ../arch/arm64/kernel/ftrace.c:231
 #9  0xffffff90101406f4 in ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:182
 Backtrace stopped: previous frame identical to this frame (corrupt stack?)
 (gdb)

Rework so that the kasan implementation isn't traced.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Anders Roxell <[email protected]>
Acked-by: Dmitry Vyukov <[email protected]>
Tested-by: Dmitry Vyukov <[email protected]>
Acked-by: Steven Rostedt (VMware) <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
mpe pushed a commit that referenced this pull request Oct 15, 2019
Reported by syzkaller:

	WARNING: CPU: 0 PID: 6544 at /home/kernel/data/kvm/arch/x86/kvm//vmx/vmx.c:4689 handle_desc+0x37/0x40 [kvm_intel]
	CPU: 0 PID: 6544 Comm: a.out Tainted: G           OE     5.3.0-rc4+ #4
	RIP: 0010:handle_desc+0x37/0x40 [kvm_intel]
	Call Trace:
	 vmx_handle_exit+0xbe/0x6b0 [kvm_intel]
	 vcpu_enter_guest+0x4dc/0x18d0 [kvm]
	 kvm_arch_vcpu_ioctl_run+0x407/0x660 [kvm]
	 kvm_vcpu_ioctl+0x3ad/0x690 [kvm]
	 do_vfs_ioctl+0xa2/0x690
	 ksys_ioctl+0x6d/0x80
	 __x64_sys_ioctl+0x1a/0x20
	 do_syscall_64+0x74/0x720
	 entry_SYSCALL_64_after_hwframe+0x49/0xbe

When CR4.UMIP is set, guest should have UMIP cpuid flag. Current
kvm set_sregs function doesn't have such check when userspace inputs
sregs values. SECONDARY_EXEC_DESC is enabled on writes to CR4.UMIP
in vmx_set_cr4 though guest doesn't have UMIP cpuid flag. The testcast
triggers handle_desc warning when executing ltr instruction since
guest architectural CR4 doesn't set UMIP. This patch fixes it by
adding valid CR4 and CPUID combination checking in __set_sregs.

syzkaller source: https://syzkaller.appspot.com/x/repro.c?x=138efb99600000

Reported-by: [email protected]
Cc: [email protected]
Signed-off-by: Wanpeng Li <[email protected]>
Reviewed-by: Sean Christopherson <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
mpe pushed a commit that referenced this pull request Mar 4, 2020
After bond_release(), netdev_update_lockdep_key() should be called.
But both ioctl path and attribute path don't call
netdev_update_lockdep_key().
This patch adds missing netdev_update_lockdep_key().

Test commands:
    ip link add bond0 type bond
    ip link add bond1 type bond
    ifenslave bond0 bond1
    ifenslave -d bond0 bond1
    ifenslave bond1 bond0

Splat looks like:
[   29.501182][ T1046] WARNING: possible circular locking dependency detected
[   29.501945][ T1039] hardirqs last disabled at (1962): [<ffffffffac6c807f>] handle_mm_fault+0x13f/0x700
[   29.503442][ T1046] 5.5.0+ torvalds#322 Not tainted
[   29.503447][ T1046] ------------------------------------------------------
[   29.504277][ T1039] softirqs last  enabled at (1180): [<ffffffffade00678>] __do_softirq+0x678/0x981
[   29.505443][ T1046] ifenslave/1046 is trying to acquire lock:
[   29.505886][ T1039] softirqs last disabled at (1169): [<ffffffffac19c18a>] irq_exit+0x17a/0x1a0
[   29.509997][ T1046] ffff88805d5da280 (&dev->addr_list_lock_key#3){+...}, at: dev_mc_sync_multiple+0x95/0x120
[   29.511243][ T1046]
[   29.511243][ T1046] but task is already holding lock:
[   29.512192][ T1046] ffff8880460f2280 (&dev->addr_list_lock_key#4){+...}, at: bond_enslave+0x4482/0x47b0 [bonding]
[   29.514124][ T1046]
[   29.514124][ T1046] which lock already depends on the new lock.
[   29.514124][ T1046]
[   29.517297][ T1046]
[   29.517297][ T1046] the existing dependency chain (in reverse order) is:
[   29.518231][ T1046]
[   29.518231][ T1046] -> #1 (&dev->addr_list_lock_key#4){+...}:
[   29.519076][ T1046]        _raw_spin_lock+0x30/0x70
[   29.519588][ T1046]        dev_mc_sync_multiple+0x95/0x120
[   29.520208][ T1046]        bond_enslave+0x448d/0x47b0 [bonding]
[   29.520862][ T1046]        bond_option_slaves_set+0x1a3/0x370 [bonding]
[   29.521640][ T1046]        __bond_opt_set+0x1ff/0xbb0 [bonding]
[   29.522438][ T1046]        __bond_opt_set_notify+0x2b/0xf0 [bonding]
[   29.523251][ T1046]        bond_opt_tryset_rtnl+0x92/0xf0 [bonding]
[   29.524082][ T1046]        bonding_sysfs_store_option+0x8a/0xf0 [bonding]
[   29.524959][ T1046]        kernfs_fop_write+0x276/0x410
[   29.525620][ T1046]        vfs_write+0x197/0x4a0
[   29.526218][ T1046]        ksys_write+0x141/0x1d0
[   29.526818][ T1046]        do_syscall_64+0x99/0x4f0
[   29.527430][ T1046]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   29.528265][ T1046]
[   29.528265][ T1046] -> #0 (&dev->addr_list_lock_key#3){+...}:
[   29.529272][ T1046]        __lock_acquire+0x2d8d/0x3de0
[   29.529935][ T1046]        lock_acquire+0x164/0x3b0
[   29.530638][ T1046]        _raw_spin_lock+0x30/0x70
[   29.531187][ T1046]        dev_mc_sync_multiple+0x95/0x120
[   29.531790][ T1046]        bond_enslave+0x448d/0x47b0 [bonding]
[   29.532451][ T1046]        bond_option_slaves_set+0x1a3/0x370 [bonding]
[   29.533163][ T1046]        __bond_opt_set+0x1ff/0xbb0 [bonding]
[   29.533789][ T1046]        __bond_opt_set_notify+0x2b/0xf0 [bonding]
[   29.534595][ T1046]        bond_opt_tryset_rtnl+0x92/0xf0 [bonding]
[   29.535500][ T1046]        bonding_sysfs_store_option+0x8a/0xf0 [bonding]
[   29.536379][ T1046]        kernfs_fop_write+0x276/0x410
[   29.537057][ T1046]        vfs_write+0x197/0x4a0
[   29.537640][ T1046]        ksys_write+0x141/0x1d0
[   29.538251][ T1046]        do_syscall_64+0x99/0x4f0
[   29.538870][ T1046]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   29.539659][ T1046]
[   29.539659][ T1046] other info that might help us debug this:
[   29.539659][ T1046]
[   29.540953][ T1046]  Possible unsafe locking scenario:
[   29.540953][ T1046]
[   29.541883][ T1046]        CPU0                    CPU1
[   29.542540][ T1046]        ----                    ----
[   29.543209][ T1046]   lock(&dev->addr_list_lock_key#4);
[   29.543880][ T1046]                                lock(&dev->addr_list_lock_key#3);
[   29.544873][ T1046]                                lock(&dev->addr_list_lock_key#4);
[   29.545863][ T1046]   lock(&dev->addr_list_lock_key#3);
[   29.546525][ T1046]
[   29.546525][ T1046]  *** DEADLOCK ***
[   29.546525][ T1046]
[   29.547542][ T1046] 5 locks held by ifenslave/1046:
[   29.548196][ T1046]  #0: ffff88806044c478 (sb_writers#5){.+.+}, at: vfs_write+0x3bb/0x4a0
[   29.549248][ T1046]  #1: ffff88805af00890 (&of->mutex){+.+.}, at: kernfs_fop_write+0x1cf/0x410
[   29.550343][ T1046]  #2: ffff88805b8b54b0 (kn->count#157){.+.+}, at: kernfs_fop_write+0x1f2/0x410
[   29.551575][ T1046]  #3: ffffffffaecf4cf0 (rtnl_mutex){+.+.}, at: bond_opt_tryset_rtnl+0x5f/0xf0 [bonding]
[   29.552819][ T1046]  #4: ffff8880460f2280 (&dev->addr_list_lock_key#4){+...}, at: bond_enslave+0x4482/0x47b0 [bonding]
[   29.554175][ T1046]
[   29.554175][ T1046] stack backtrace:
[   29.554907][ T1046] CPU: 0 PID: 1046 Comm: ifenslave Not tainted 5.5.0+ torvalds#322
[   29.555854][ T1046] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[   29.557064][ T1046] Call Trace:
[   29.557504][ T1046]  dump_stack+0x96/0xdb
[   29.558054][ T1046]  check_noncircular+0x371/0x450
[   29.558723][ T1046]  ? print_circular_bug.isra.35+0x310/0x310
[   29.559486][ T1046]  ? hlock_class+0x130/0x130
[   29.560100][ T1046]  ? __lock_acquire+0x2d8d/0x3de0
[   29.560761][ T1046]  __lock_acquire+0x2d8d/0x3de0
[   29.561366][ T1046]  ? register_lock_class+0x14d0/0x14d0
[   29.562045][ T1046]  ? find_held_lock+0x39/0x1d0
[   29.562641][ T1046]  lock_acquire+0x164/0x3b0
[   29.563199][ T1046]  ? dev_mc_sync_multiple+0x95/0x120
[   29.563872][ T1046]  _raw_spin_lock+0x30/0x70
[   29.564464][ T1046]  ? dev_mc_sync_multiple+0x95/0x120
[   29.565146][ T1046]  dev_mc_sync_multiple+0x95/0x120
[   29.565793][ T1046]  bond_enslave+0x448d/0x47b0 [bonding]
[   29.566487][ T1046]  ? bond_update_slave_arr+0x940/0x940 [bonding]
[   29.567279][ T1046]  ? bstr_printf+0xc20/0xc20
[   29.567857][ T1046]  ? stack_trace_consume_entry+0x160/0x160
[   29.568614][ T1046]  ? deactivate_slab.isra.77+0x2c5/0x800
[   29.569320][ T1046]  ? check_chain_key+0x236/0x5d0
[   29.569939][ T1046]  ? sscanf+0x93/0xc0
[   29.570442][ T1046]  ? vsscanf+0x1e20/0x1e20
[   29.571003][ T1046]  bond_option_slaves_set+0x1a3/0x370 [bonding]
[ ... ]

Fixes: ab92d68 ("net: core: add generic lockdep keys")
Signed-off-by: Taehee Yoo <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
mpe pushed a commit that referenced this pull request Mar 4, 2020
The only time we actually leave the path spinning is if we're truncating
a small amount and don't actually free an extent, which is not a common
occurrence.  We have to set the path blocking in order to add the
delayed ref anyway, so the first extent we find we set the path to
blocking and stay blocking for the duration of the operation.  With the
upcoming file extent map stuff there will be another case that we have
to have the path blocking, so just swap to blocking always.

Note: this patch also fixes a warning after 28553fa ("Btrfs: fix
race between shrinking truncate and fiemap") got merged that inserts
extent locks around truncation so the path must not leave spinning locks
after btrfs_search_slot.

  [70.794783] BUG: sleeping function called from invalid context at mm/slab.h:565
  [70.794834] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1141, name: rsync
  [70.794863] 5 locks held by rsync/1141:
  [70.794876]  #0: ffff888417b9c408 (sb_writers#17){.+.+}, at: mnt_want_write+0x20/0x50
  [70.795030]  #1: ffff888428de28e8 (&type->i_mutex_dir_key#13/1){+.+.}, at: lock_rename+0xf1/0x100
  [70.795051]  #2: ffff888417b9c608 (sb_internal#2){.+.+}, at: start_transaction+0x394/0x560
  [70.795124]  #3: ffff888403081768 (btrfs-fs-01){++++}, at: btrfs_try_tree_write_lock+0x2f/0x160
  [70.795203]  #4: ffff888403086568 (btrfs-fs-00){++++}, at: btrfs_try_tree_write_lock+0x2f/0x160
  [70.795222] CPU: 5 PID: 1141 Comm: rsync Not tainted 5.6.0-rc2-backup+ #2
  [70.795362] Call Trace:
  [70.795374]  dump_stack+0x71/0xa0
  [70.795445]  ___might_sleep.part.96.cold.106+0xa6/0xb6
  [70.795459]  kmem_cache_alloc+0x1d3/0x290
  [70.795471]  alloc_extent_state+0x22/0x1c0
  [70.795544]  __clear_extent_bit+0x3ba/0x580
  [70.795557]  ? _raw_spin_unlock_irq+0x24/0x30
  [70.795569]  btrfs_truncate_inode_items+0x339/0xe50
  [70.795647]  btrfs_evict_inode+0x269/0x540
  [70.795659]  ? dput.part.38+0x29/0x460
  [70.795671]  evict+0xcd/0x190
  [70.795682]  __dentry_kill+0xd6/0x180
  [70.795754]  dput.part.38+0x2ad/0x460
  [70.795765]  do_renameat2+0x3cb/0x540
  [70.795777]  __x64_sys_rename+0x1c/0x20

Reported-by: Dave Jones <[email protected]>
Fixes: 28553fa ("Btrfs: fix race between shrinking truncate and fiemap")
CC: [email protected] # 4.4+
Reviewed-by: Filipe Manana <[email protected]>
Signed-off-by: Josef Bacik <[email protected]>
Reviewed-by: David Sterba <[email protected]>
[ add note ]
Signed-off-by: David Sterba <[email protected]>
mpe pushed a commit that referenced this pull request Mar 4, 2020
rmnet_get_port() internally calls rcu_dereference_rtnl(),
which checks RTNL.
But rmnet_get_port() could be called by packet path.
The packet path is not protected by RTNL.
So, the suspicious RCU usage problem occurs.

Test commands:
    modprobe rmnet
    ip netns add nst
    ip link add veth0 type veth peer name veth1
    ip link set veth1 netns nst
    ip link add rmnet0 link veth0 type rmnet mux_id 1
    ip netns exec nst ip link add rmnet1 link veth1 type rmnet mux_id 1
    ip netns exec nst ip link set veth1 up
    ip netns exec nst ip link set rmnet1 up
    ip netns exec nst ip a a 192.168.100.2/24 dev rmnet1
    ip link set veth0 up
    ip link set rmnet0 up
    ip a a 192.168.100.1/24 dev rmnet0
    ping 192.168.100.2

Splat looks like:
[  146.630958][ T1174] WARNING: suspicious RCU usage
[  146.631735][ T1174] 5.6.0-rc1+ torvalds#447 Not tainted
[  146.632387][ T1174] -----------------------------
[  146.633151][ T1174] drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c:386 suspicious rcu_dereference_check() !
[  146.634742][ T1174]
[  146.634742][ T1174] other info that might help us debug this:
[  146.634742][ T1174]
[  146.645992][ T1174]
[  146.645992][ T1174] rcu_scheduler_active = 2, debug_locks = 1
[  146.646937][ T1174] 5 locks held by ping/1174:
[  146.647609][ T1174]  #0: ffff8880c31dea70 (sk_lock-AF_INET){+.+.}, at: raw_sendmsg+0xab8/0x2980
[  146.662463][ T1174]  #1: ffffffff93925660 (rcu_read_lock_bh){....}, at: ip_finish_output2+0x243/0x2150
[  146.671696][ T1174]  #2: ffffffff93925660 (rcu_read_lock_bh){....}, at: __dev_queue_xmit+0x213/0x2940
[  146.673064][ T1174]  #3: ffff8880c19ecd58 (&dev->qdisc_running_key#7){+...}, at: ip_finish_output2+0x714/0x2150
[  146.690358][ T1174]  #4: ffff8880c5796898 (&dev->qdisc_xmit_lock_key#3){+.-.}, at: sch_direct_xmit+0x1e2/0x1020
[  146.699875][ T1174]
[  146.699875][ T1174] stack backtrace:
[  146.701091][ T1174] CPU: 0 PID: 1174 Comm: ping Not tainted 5.6.0-rc1+ torvalds#447
[  146.705215][ T1174] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[  146.706565][ T1174] Call Trace:
[  146.707102][ T1174]  dump_stack+0x96/0xdb
[  146.708007][ T1174]  rmnet_get_port.part.9+0x76/0x80 [rmnet]
[  146.709233][ T1174]  rmnet_egress_handler+0x107/0x420 [rmnet]
[  146.710492][ T1174]  ? sch_direct_xmit+0x1e2/0x1020
[  146.716193][ T1174]  rmnet_vnd_start_xmit+0x3d/0xa0 [rmnet]
[  146.717012][ T1174]  dev_hard_start_xmit+0x160/0x740
[  146.717854][ T1174]  sch_direct_xmit+0x265/0x1020
[  146.718577][ T1174]  ? register_lock_class+0x14d0/0x14d0
[  146.719429][ T1174]  ? dev_watchdog+0xac0/0xac0
[  146.723738][ T1174]  ? __dev_queue_xmit+0x15fd/0x2940
[  146.724469][ T1174]  ? lock_acquire+0x164/0x3b0
[  146.725172][ T1174]  __dev_queue_xmit+0x20c7/0x2940
[ ... ]

Fixes: ceed73a ("drivers: net: ethernet: qualcomm: rmnet: Initial implementation")
Signed-off-by: Taehee Yoo <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
mpe pushed a commit that referenced this pull request Mar 4, 2020
journal_head::b_transaction and journal_head::b_next_transaction could
be accessed concurrently as noticed by KCSAN,

 LTP: starting fsync04
 /dev/zero: Can't open blockdev
 EXT4-fs (loop0): mounting ext3 file system using the ext4 subsystem
 EXT4-fs (loop0): mounted filesystem with ordered data mode. Opts: (null)
 ==================================================================
 BUG: KCSAN: data-race in __jbd2_journal_refile_buffer [jbd2] / jbd2_write_access_granted [jbd2]

 write to 0xffff99f9b1bd0e30 of 8 bytes by task 25721 on cpu 70:
  __jbd2_journal_refile_buffer+0xdd/0x210 [jbd2]
  __jbd2_journal_refile_buffer at fs/jbd2/transaction.c:2569
  jbd2_journal_commit_transaction+0x2d15/0x3f20 [jbd2]
  (inlined by) jbd2_journal_commit_transaction at fs/jbd2/commit.c:1034
  kjournald2+0x13b/0x450 [jbd2]
  kthread+0x1cd/0x1f0
  ret_from_fork+0x27/0x50

 read to 0xffff99f9b1bd0e30 of 8 bytes by task 25724 on cpu 68:
  jbd2_write_access_granted+0x1b2/0x250 [jbd2]
  jbd2_write_access_granted at fs/jbd2/transaction.c:1155
  jbd2_journal_get_write_access+0x2c/0x60 [jbd2]
  __ext4_journal_get_write_access+0x50/0x90 [ext4]
  ext4_mb_mark_diskspace_used+0x158/0x620 [ext4]
  ext4_mb_new_blocks+0x54f/0xca0 [ext4]
  ext4_ind_map_blocks+0xc79/0x1b40 [ext4]
  ext4_map_blocks+0x3b4/0x950 [ext4]
  _ext4_get_block+0xfc/0x270 [ext4]
  ext4_get_block+0x3b/0x50 [ext4]
  __block_write_begin_int+0x22e/0xae0
  __block_write_begin+0x39/0x50
  ext4_write_begin+0x388/0xb50 [ext4]
  generic_perform_write+0x15d/0x290
  ext4_buffered_write_iter+0x11f/0x210 [ext4]
  ext4_file_write_iter+0xce/0x9e0 [ext4]
  new_sync_write+0x29c/0x3b0
  __vfs_write+0x92/0xa0
  vfs_write+0x103/0x260
  ksys_write+0x9d/0x130
  __x64_sys_write+0x4c/0x60
  do_syscall_64+0x91/0xb05
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

 5 locks held by fsync04/25724:
  #0: ffff99f9911093f8 (sb_writers#13){.+.+}, at: vfs_write+0x21c/0x260
  #1: ffff99f9db4c0348 (&sb->s_type->i_mutex_key#15){+.+.}, at: ext4_buffered_write_iter+0x65/0x210 [ext4]
  #2: ffff99f5e7dfcf58 (jbd2_handle){++++}, at: start_this_handle+0x1c1/0x9d0 [jbd2]
  #3: ffff99f9db4c0168 (&ei->i_data_sem){++++}, at: ext4_map_blocks+0x176/0x950 [ext4]
  #4: ffffffff99086b40 (rcu_read_lock){....}, at: jbd2_write_access_granted+0x4e/0x250 [jbd2]
 irq event stamp: 1407125
 hardirqs last  enabled at (1407125): [<ffffffff980da9b7>] __find_get_block+0x107/0x790
 hardirqs last disabled at (1407124): [<ffffffff980da8f9>] __find_get_block+0x49/0x790
 softirqs last  enabled at (1405528): [<ffffffff98a0034c>] __do_softirq+0x34c/0x57c
 softirqs last disabled at (1405521): [<ffffffff97cc67a2>] irq_exit+0xa2/0xc0

 Reported by Kernel Concurrency Sanitizer on:
 CPU: 68 PID: 25724 Comm: fsync04 Tainted: G L 5.6.0-rc2-next-20200221+ #7
 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019

The plain reads are outside of jh->b_state_lock critical section which result
in data races. Fix them by adding pairs of READ|WRITE_ONCE().

Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: Qian Cai <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
mpe pushed a commit that referenced this pull request Feb 8, 2021
If dobj->control is not initialized we end up in an OOPs during
skl_tplg_complete:

[   26.553358] BUG: kernel NULL pointer dereference, address:
0000000000000078
[   26.561151] #PF: supervisor read access in kernel mode
[   26.566897] #PF: error_code(0x0000) - not-present page
[   26.572642] PGD 0 P4D 0
[   26.575479] Oops: 0000 [#1] PREEMPT SMP PTI
[   26.580158] CPU: 2 PID: 2082 Comm: udevd Tainted: G         C
5.4.81 #4
[   26.588232] Hardware name: HP Soraka/Soraka, BIOS
Google_Soraka.10431.106.0 12/03/2019
[   26.597082] RIP: 0010:skl_tplg_complete+0x70/0x144 [snd_soc_skl]

Fixes: 2d744ec ("ASoC: Intel: Skylake: Automatic DMIC format configuration according to information from NHL")
Signed-off-by: Ricardo Ribalda <[email protected]>
Reviewed-by: Cezary Rojewski <[email protected]>
Tested-by: Lukasz Majczak <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>
mpe pushed a commit that referenced this pull request Feb 8, 2021
Since at91_soc_init is called unconditionally from atmel_soc_device_init,
we get the following warning on all non AT91 SoCs:
	" AT91: Could not find identification node"

Fix the same by filtering with allowed AT91 SoC list.

Cc: Nicolas Ferre <[email protected]>
Cc: Alexandre Belloni <[email protected]>
Cc: Ludovic Desroches <[email protected]>
Cc: [email protected] #4.12+
Signed-off-by: Sudeep Holla <[email protected]>
Signed-off-by: Alexandre Belloni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnd Bergmann <[email protected]>
mpe pushed a commit that referenced this pull request Feb 8, 2021
…st[]

of_match_node() calls __of_match_node() which loops though the entries of
matches array. It stops when condition:
(matches->name[0] || matches->type[0] || matches->compatible[0]) is
false. Thus, add a null entry at the end of at91_soc_allowed_list[]
array.

Fixes: caab13b ("drivers: soc: atmel: Avoid calling at91_soc_init on non AT91 SoCs")
Cc: [email protected] #4.12+
Signed-off-by: Claudiu Beznea <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
mpe pushed a commit that referenced this pull request Feb 8, 2021
Without __GFP_NOWARN, attempts at allocating huge pages can trigger
dmesg splats like below (which are essentially noise, since TTM falls
back to normal pages if it can't get a huge one).

[ 9556.710241] clinfo: page allocation failure: order:9, mode:0x194dc2(GFP_HIGHUSER|__GFP_RETRY_MAYFAIL|__GFP_NORETRY|__GFP_ZERO|__GFP_NOMEMALLOC), nodemask=(null),cpuset=user.slice,mems_allowed=0
[ 9556.710259] CPU: 1 PID: 470821 Comm: clinfo Tainted: G            E     5.10.10+ #4
[ 9556.710264] Hardware name: Micro-Star International Co., Ltd. MS-7A34/B350 TOMAHAWK (MS-7A34), BIOS 1.OR 11/29/2019
[ 9556.710268] Call Trace:
[ 9556.710281]  dump_stack+0x6b/0x83
[ 9556.710288]  warn_alloc.cold+0x7b/0xdf
[ 9556.710297]  ? __alloc_pages_direct_compact+0x137/0x150
[ 9556.710303]  __alloc_pages_slowpath.constprop.0+0xc1b/0xc50
[ 9556.710312]  __alloc_pages_nodemask+0x2ec/0x320
[ 9556.710325]  ttm_pool_alloc+0x2e4/0x5e0 [ttm]
[ 9556.710332]  ? kvmalloc_node+0x46/0x80
[ 9556.710341]  ttm_tt_populate+0x37/0xe0 [ttm]
[ 9556.710350]  ttm_bo_handle_move_mem+0x142/0x180 [ttm]
[ 9556.710359]  ttm_bo_validate+0x11d/0x190 [ttm]
[ 9556.710391]  ? drm_vma_offset_add+0x2f/0x60 [drm]
[ 9556.710399]  ttm_bo_init_reserved+0x2a7/0x320 [ttm]
[ 9556.710529]  amdgpu_bo_do_create+0x1b8/0x500 [amdgpu]
[ 9556.710657]  ? amdgpu_bo_subtract_pin_size+0x60/0x60 [amdgpu]
[ 9556.710663]  ? get_page_from_freelist+0x11f9/0x1450
[ 9556.710789]  amdgpu_bo_create+0x40/0x270 [amdgpu]
[ 9556.710797]  ? _raw_spin_unlock+0x16/0x30
[ 9556.710927]  amdgpu_gem_create_ioctl+0x123/0x310 [amdgpu]
[ 9556.711062]  ? amdgpu_gem_force_release+0x150/0x150 [amdgpu]
[ 9556.711098]  drm_ioctl_kernel+0xaa/0xf0 [drm]
[ 9556.711133]  drm_ioctl+0x20f/0x3a0 [drm]
[ 9556.711267]  ? amdgpu_gem_force_release+0x150/0x150 [amdgpu]
[ 9556.711276]  ? preempt_count_sub+0x9b/0xd0
[ 9556.711404]  amdgpu_drm_ioctl+0x49/0x80 [amdgpu]
[ 9556.711411]  __x64_sys_ioctl+0x83/0xb0
[ 9556.711417]  do_syscall_64+0x33/0x80
[ 9556.711421]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: bf9eee2 ("drm/ttm: stop using GFP_TRANSHUGE_LIGHT")
Signed-off-by: Michel Dänzer <[email protected]>
Reviewed-by: Christian König <[email protected]>
Signed-off-by: Christian König <[email protected]>
Link: https://patchwork.freedesktop.org/patch/416353/
mpe pushed a commit that referenced this pull request May 24, 2021
…xtent

When cloning an inline extent there are a few cases, such as when we have
an implicit hole at file offset 0, where we start a transaction while
holding a read lock on a leaf. Starting the transaction results in a call
to sb_start_intwrite(), which results in doing a read lock on a percpu
semaphore. Lockdep doesn't like this and complains about it:

  [46.580704] ======================================================
  [46.580752] WARNING: possible circular locking dependency detected
  [46.580799] 5.13.0-rc1 torvalds#28 Not tainted
  [46.580832] ------------------------------------------------------
  [46.580877] cloner/3835 is trying to acquire lock:
  [46.580918] c00000001301d638 (sb_internal#2){.+.+}-{0:0}, at: clone_copy_inline_extent+0xe4/0x5a0
  [46.581167]
  [46.581167] but task is already holding lock:
  [46.581217] c000000007fa2550 (btrfs-tree-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x70/0x1d0
  [46.581293]
  [46.581293] which lock already depends on the new lock.
  [46.581293]
  [46.581351]
  [46.581351] the existing dependency chain (in reverse order) is:
  [46.581410]
  [46.581410] -> #1 (btrfs-tree-00){++++}-{3:3}:
  [46.581464]        down_read_nested+0x68/0x200
  [46.581536]        __btrfs_tree_read_lock+0x70/0x1d0
  [46.581577]        btrfs_read_lock_root_node+0x88/0x200
  [46.581623]        btrfs_search_slot+0x298/0xb70
  [46.581665]        btrfs_set_inode_index+0xfc/0x260
  [46.581708]        btrfs_new_inode+0x26c/0x950
  [46.581749]        btrfs_create+0xf4/0x2b0
  [46.581782]        lookup_open.isra.57+0x55c/0x6a0
  [46.581855]        path_openat+0x418/0xd20
  [46.581888]        do_filp_open+0x9c/0x130
  [46.581920]        do_sys_openat2+0x2ec/0x430
  [46.581961]        do_sys_open+0x90/0xc0
  [46.581993]        system_call_exception+0x3d4/0x410
  [46.582037]        system_call_common+0xec/0x278
  [46.582078]
  [46.582078] -> #0 (sb_internal#2){.+.+}-{0:0}:
  [46.582135]        __lock_acquire+0x1e90/0x2c50
  [46.582176]        lock_acquire+0x2b4/0x5b0
  [46.582263]        start_transaction+0x3cc/0x950
  [46.582308]        clone_copy_inline_extent+0xe4/0x5a0
  [46.582353]        btrfs_clone+0x5fc/0x880
  [46.582388]        btrfs_clone_files+0xd8/0x1c0
  [46.582434]        btrfs_remap_file_range+0x3d8/0x590
  [46.582481]        do_clone_file_range+0x10c/0x270
  [46.582558]        vfs_clone_file_range+0x1b0/0x310
  [46.582605]        ioctl_file_clone+0x90/0x130
  [46.582651]        do_vfs_ioctl+0x874/0x1ac0
  [46.582697]        sys_ioctl+0x6c/0x120
  [46.582733]        system_call_exception+0x3d4/0x410
  [46.582777]        system_call_common+0xec/0x278
  [46.582822]
  [46.582822] other info that might help us debug this:
  [46.582822]
  [46.582888]  Possible unsafe locking scenario:
  [46.582888]
  [46.582942]        CPU0                    CPU1
  [46.582984]        ----                    ----
  [46.583028]   lock(btrfs-tree-00);
  [46.583062]                                lock(sb_internal#2);
  [46.583119]                                lock(btrfs-tree-00);
  [46.583174]   lock(sb_internal#2);
  [46.583212]
  [46.583212]  *** DEADLOCK ***
  [46.583212]
  [46.583266] 6 locks held by cloner/3835:
  [46.583299]  #0: c00000001301d448 (sb_writers#12){.+.+}-{0:0}, at: ioctl_file_clone+0x90/0x130
  [46.583382]  #1: c00000000f6d3768 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: lock_two_nondirectories+0x58/0xc0
  [46.583477]  #2: c00000000f6d72a8 (&sb->s_type->i_mutex_key#15/4){+.+.}-{3:3}, at: lock_two_nondirectories+0x9c/0xc0
  [46.583574]  #3: c00000000f6d7138 (&ei->i_mmap_lock){+.+.}-{3:3}, at: btrfs_remap_file_range+0xd0/0x590
  [46.583657]  #4: c00000000f6d35f8 (&ei->i_mmap_lock/1){+.+.}-{3:3}, at: btrfs_remap_file_range+0xe0/0x590
  [46.583743]  #5: c000000007fa2550 (btrfs-tree-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x70/0x1d0
  [46.583828]
  [46.583828] stack backtrace:
  [46.583872] CPU: 1 PID: 3835 Comm: cloner Not tainted 5.13.0-rc1 torvalds#28
  [46.583931] Call Trace:
  [46.583955] [c0000000167c7200] [c000000000c1ee78] dump_stack+0xec/0x144 (unreliable)
  [46.584052] [c0000000167c7240] [c000000000274058] print_circular_bug.isra.32+0x3a8/0x400
  [46.584123] [c0000000167c72e0] [c0000000002741f4] check_noncircular+0x144/0x190
  [46.584191] [c0000000167c73b0] [c000000000278fc0] __lock_acquire+0x1e90/0x2c50
  [46.584259] [c0000000167c74f0] [c00000000027aa94] lock_acquire+0x2b4/0x5b0
  [46.584317] [c0000000167c75e0] [c000000000a0d6cc] start_transaction+0x3cc/0x950
  [46.584388] [c0000000167c7690] [c000000000af47a4] clone_copy_inline_extent+0xe4/0x5a0
  [46.584457] [c0000000167c77c0] [c000000000af525c] btrfs_clone+0x5fc/0x880
  [46.584514] [c0000000167c7990] [c000000000af5698] btrfs_clone_files+0xd8/0x1c0
  [46.584583] [c0000000167c7a00] [c000000000af5b58] btrfs_remap_file_range+0x3d8/0x590
  [46.584652] [c0000000167c7ae0] [c0000000005d81dc] do_clone_file_range+0x10c/0x270
  [46.584722] [c0000000167c7b40] [c0000000005d84f0] vfs_clone_file_range+0x1b0/0x310
  [46.584793] [c0000000167c7bb0] [c00000000058bf80] ioctl_file_clone+0x90/0x130
  [46.584861] [c0000000167c7c10] [c00000000058c894] do_vfs_ioctl+0x874/0x1ac0
  [46.584922] [c0000000167c7d10] [c00000000058db4c] sys_ioctl+0x6c/0x120
  [46.584978] [c0000000167c7d60] [c0000000000364a4] system_call_exception+0x3d4/0x410
  [46.585046] [c0000000167c7e10] [c00000000000d45c] system_call_common+0xec/0x278
  [46.585114] --- interrupt: c00 at 0x7ffff7e22990
  [46.585160] NIP:  00007ffff7e22990 LR: 00000001000010ec CTR: 0000000000000000
  [46.585224] REGS: c0000000167c7e80 TRAP: 0c00   Not tainted  (5.13.0-rc1)
  [46.585280] MSR:  800000000280f033 <SF,VEC,VSX,EE,PR,FP,ME,IR,DR,RI,LE>  CR: 28000244  XER: 00000000
  [46.585374] IRQMASK: 0
  [46.585374] GPR00: 0000000000000036 00007fffffffdec0 00007ffff7f17100 0000000000000004
  [46.585374] GPR04: 000000008020940d 00007fffffffdf40 0000000000000000 0000000000000000
  [46.585374] GPR08: 0000000000000004 0000000000000000 0000000000000000 0000000000000000
  [46.585374] GPR12: 0000000000000000 00007ffff7ffa940 0000000000000000 0000000000000000
  [46.585374] GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
  [46.585374] GPR20: 0000000000000000 000000009123683e 00007fffffffdf40 0000000000000000
  [46.585374] GPR24: 0000000000000000 0000000000000000 0000000000000000 0000000000000004
  [46.585374] GPR28: 0000000100030260 0000000100030280 0000000000000003 000000000000005f
  [46.585919] NIP [00007ffff7e22990] 0x7ffff7e22990
  [46.585964] LR [00000001000010ec] 0x1000010ec
  [46.586010] --- interrupt: c00

This should be a false positive, as both locks are acquired in read mode.
Nevertheless, we don't need to hold a leaf locked when we start the
transaction, so just release the leaf (path) before starting it.

Reported-by: Ritesh Harjani <[email protected]>
Link: https://lore.kernel.org/linux-btrfs/20210513214404.xks77p566fglzgum@riteshh-domain/
Reviewed-by: Anand Jain <[email protected]>
Signed-off-by: Filipe Manana <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>
mpe pushed a commit that referenced this pull request Jun 21, 2021
   WARNING: suspicious RCU usage
   5.13.0-rc1 #4 Not tainted
   -----------------------------
   ./include/linux/kvm_host.h:710 suspicious rcu_dereference_check() usage!

  other info that might help us debug this:

  rcu_scheduler_active = 2, debug_locks = 1
   1 lock held by hyperv_clock/8318:
    #0: ffffb6b8cb05a7d8 (&hv->hv_lock){+.+.}-{3:3}, at: kvm_hv_invalidate_tsc_page+0x3e/0xa0 [kvm]

  stack backtrace:
  CPU: 3 PID: 8318 Comm: hyperv_clock Not tainted 5.13.0-rc1 #4
  Call Trace:
   dump_stack+0x87/0xb7
   lockdep_rcu_suspicious+0xce/0xf0
   kvm_write_guest_page+0x1c1/0x1d0 [kvm]
   kvm_write_guest+0x50/0x90 [kvm]
   kvm_hv_invalidate_tsc_page+0x79/0xa0 [kvm]
   kvm_gen_update_masterclock+0x1d/0x110 [kvm]
   kvm_arch_vm_ioctl+0x2a7/0xc50 [kvm]
   kvm_vm_ioctl+0x123/0x11d0 [kvm]
   __x64_sys_ioctl+0x3ed/0x9d0
   do_syscall_64+0x3d/0x80
   entry_SYSCALL_64_after_hwframe+0x44/0xae

kvm_memslots() will be called by kvm_write_guest(), so we should take the srcu lock.

Fixes: e880c6e (KVM: x86: hyper-v: Prevent using not-yet-updated TSC page by secondary CPUs)
Reviewed-by: Vitaly Kuznetsov <[email protected]>
Signed-off-by: Wanpeng Li <[email protected]>
Message-Id: <[email protected]>
Reviewed-by: Sean Christopherson <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
mpe pushed a commit that referenced this pull request Jun 21, 2021
ASan reported a memory leak caused by info_linear not being deallocated.

The info_linear was allocated during in perf_event__synthesize_one_bpf_prog().

This patch adds the corresponding free() when bpf_prog_info_node
is freed in perf_env__purge_bpf().

  $ sudo ./perf record -- sleep 5
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.025 MB perf.data (8 samples) ]

  =================================================================
  ==297735==ERROR: LeakSanitizer: detected memory leaks

  Direct leak of 7688 byte(s) in 19 object(s) allocated from:
      #0 0x4f420f in malloc (/home/user/linux/tools/perf/perf+0x4f420f)
      #1 0xc06a74 in bpf_program__get_prog_info_linear /home/user/linux/tools/lib/bpf/libbpf.c:11113:16
      #2 0xb426fe in perf_event__synthesize_one_bpf_prog /home/user/linux/tools/perf/util/bpf-event.c:191:16
      #3 0xb42008 in perf_event__synthesize_bpf_events /home/user/linux/tools/perf/util/bpf-event.c:410:9
      #4 0x594596 in record__synthesize /home/user/linux/tools/perf/builtin-record.c:1490:8
      #5 0x58c9ac in __cmd_record /home/user/linux/tools/perf/builtin-record.c:1798:8
      #6 0x58990b in cmd_record /home/user/linux/tools/perf/builtin-record.c:2901:8
      #7 0x7b2a20 in run_builtin /home/user/linux/tools/perf/perf.c:313:11
      #8 0x7b12ff in handle_internal_command /home/user/linux/tools/perf/perf.c:365:8
      #9 0x7b2583 in run_argv /home/user/linux/tools/perf/perf.c:409:2
      #10 0x7b0d79 in main /home/user/linux/tools/perf/perf.c:539:3
      torvalds#11 0x7fa357ef6b74 in __libc_start_main /usr/src/debug/glibc-2.33-8.fc34.x86_64/csu/../csu/libc-start.c:332:16

Signed-off-by: Riccardo Mancini <[email protected]>
Acked-by: Ian Rogers <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Andrii Nakryiko <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Fastabend <[email protected]>
Cc: KP Singh <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Martin KaFai Lau <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Song Liu <[email protected]>
Cc: Yonghong Song <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
mpe pushed a commit that referenced this pull request Jun 21, 2021
…oles on aarch64

offline_pages() properly checks for memory holes and bails out.
However, we do a page_zone(pfn_to_page(start_pfn)) before calling
offline_pages() when offlining a memory block.

We should not unconditionally call page_zone(pfn_to_page(start_pfn)) on
aarch64 in offlining code, otherwise we can trigger a BUG when hitting a
memory hole:

   kernel BUG at include/linux/mm.h:1383!
   Internal error: Oops - BUG: 0 [#1] SMP
   Modules linked in: loop processor efivarfs ip_tables x_tables ext4 mbcache jbd2 dm_mod igb nvme i2c_algo_bit mlx5_core i2c_core nvme_core firmware_class
   CPU: 13 PID: 1694 Comm: ranbug Not tainted 5.12.0-next-20210524+ #4
   Hardware name: MiTAC RAPTOR EV-883832-X3-0001/RAPTOR, BIOS 1.6 06/28/2020
   pstate: 60000005 (nZCv daif -PAN -UAO -TCO BTYPE=--)
   pc : memory_subsys_offline+0x1f8/0x250
   lr : memory_subsys_offline+0x1f8/0x250
   Call trace:
     memory_subsys_offline+0x1f8/0x250
     device_offline+0x154/0x1d8
     online_store+0xa4/0x118
     dev_attr_store+0x44/0x78
     sysfs_kf_write+0xe8/0x138
     kernfs_fop_write_iter+0x26c/0x3d0
     new_sync_write+0x2bc/0x4f8
     vfs_write+0x718/0xc88
     ksys_write+0xf8/0x1e0
     __arm64_sys_write+0x74/0xa8
     invoke_syscall.constprop.0+0x78/0x1e8
     do_el0_svc+0xe4/0x298
     el0_svc+0x20/0x30
     el0_sync_handler+0xb0/0xb8
     el0_sync+0x178/0x180
   Kernel panic - not syncing: Oops - BUG: Fatal exception
   SMP: stopping secondary CPUs
   Kernel Offset: disabled
   CPU features: 0x00000251,20000846
   Memory Limit: none

If nr_vmemmap_pages is set, we know that we are dealing with hotplugged
memory that doesn't have any holes.  So call
page_zone(pfn_to_page(start_pfn)) only when really necessary -- when
nr_vmemmap_pages is set and we actually adjust the present pages.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: a08a2ae ("mm,memory_hotplug: allocate memmap from the added memory range")
Signed-off-by: David Hildenbrand <[email protected]>
Reported-by: Qian Cai (QUIC) <[email protected]>
Reviewed-by: Oscar Salvador <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Mike Rapoport <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
mpe pushed a commit that referenced this pull request Nov 20, 2024
When CONFIG_KASAN_SW_TAGS and CONFIG_KASAN_STACK are enabled, the
object_is_on_stack() function may produce incorrect results due to the
presence of tags in the obj pointer, while the stack pointer does not have
tags.  This discrepancy can lead to incorrect stack object detection and
subsequently trigger warnings if CONFIG_DEBUG_OBJECTS is also enabled.

Example of the warning:

ODEBUG: object 3eff800082ea7bb0 is NOT on stack ffff800082ea0000, but annotated.
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at lib/debugobjects.c:557 __debug_object_init+0x330/0x364
Modules linked in:
CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.0-rc5 #4
Hardware name: linux,dummy-virt (DT)
pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __debug_object_init+0x330/0x364
lr : __debug_object_init+0x330/0x364
sp : ffff800082ea7b40
x29: ffff800082ea7b40 x28: 98ff0000c0164518 x27: 98ff0000c0164534
x26: ffff800082d93ec8 x25: 0000000000000001 x24: 1cff0000c00172a0
x23: 0000000000000000 x22: ffff800082d93ed0 x21: ffff800081a24418
x20: 3eff800082ea7bb0 x19: efff800000000000 x18: 0000000000000000
x17: 00000000000000ff x16: 0000000000000047 x15: 206b63617473206e
x14: 0000000000000018 x13: ffff800082ea7780 x12: 0ffff800082ea78e
x11: 0ffff800082ea790 x10: 0ffff800082ea79d x9 : 34d77febe173e800
x8 : 34d77febe173e800 x7 : 0000000000000001 x6 : 0000000000000001
x5 : feff800082ea74b8 x4 : ffff800082870a90 x3 : ffff80008018d3c4
x2 : 0000000000000001 x1 : ffff800082858810 x0 : 0000000000000050
Call trace:
 __debug_object_init+0x330/0x364
 debug_object_init_on_stack+0x30/0x3c
 schedule_hrtimeout_range_clock+0xac/0x26c
 schedule_hrtimeout+0x1c/0x30
 wait_task_inactive+0x1d4/0x25c
 kthread_bind_mask+0x28/0x98
 init_rescuer+0x1e8/0x280
 workqueue_init+0x1a0/0x3cc
 kernel_init_freeable+0x118/0x200
 kernel_init+0x28/0x1f0
 ret_from_fork+0x10/0x20
---[ end trace 0000000000000000 ]---
ODEBUG: object 3eff800082ea7bb0 is NOT on stack ffff800082ea0000, but annotated.
------------[ cut here ]------------

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Qun-Wei Lin <[email protected]>
Cc: Andrew Yang <[email protected]>
Cc: AngeloGioacchino Del Regno <[email protected]>
Cc: Casper Li <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Chinwen Chang <[email protected]>
Cc: Kent Overstreet <[email protected]>
Cc: Matthias Brugger <[email protected]>
Cc: Pasha Tatashin <[email protected]>
Cc: Shakeel Butt <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
mpe pushed a commit that referenced this pull request Mar 16, 2025
Use raw_spinlock in order to fix spurious messages about invalid context
when spinlock debugging is enabled. The lock is only used to serialize
register access.

    [    4.239592] =============================
    [    4.239595] [ BUG: Invalid wait context ]
    [    4.239599] 6.13.0-rc7-arm64-renesas-05496-gd088502a519f torvalds#35 Not tainted
    [    4.239603] -----------------------------
    [    4.239606] kworker/u8:5/76 is trying to lock:
    [    4.239609] ffff0000091898a0 (&p->lock){....}-{3:3}, at: gpio_rcar_config_interrupt_input_mode+0x34/0x164
    [    4.239641] other info that might help us debug this:
    [    4.239643] context-{5:5}
    [    4.239646] 5 locks held by kworker/u8:5/76:
    [    4.239651]  #0: ffff0000080fb148 ((wq_completion)async){+.+.}-{0:0}, at: process_one_work+0x190/0x62c
    [    4.250180] OF: /soc/sound@ec500000/ports/port@0/endpoint: Read of boolean property 'frame-master' with a value.
    [    4.254094]  #1: ffff80008299bd80 ((work_completion)(&entry->work)){+.+.}-{0:0}, at: process_one_work+0x1b8/0x62c
    [    4.254109]  #2: ffff00000920c8f8
    [    4.258345] OF: /soc/sound@ec500000/ports/port@1/endpoint: Read of boolean property 'bitclock-master' with a value.
    [    4.264803]  (&dev->mutex){....}-{4:4}, at: __device_attach_async_helper+0x3c/0xdc
    [    4.264820]  #3: ffff00000a50ca40 (request_class#2){+.+.}-{4:4}, at: __setup_irq+0xa0/0x690
    [    4.264840]  #4:
    [    4.268872] OF: /soc/sound@ec500000/ports/port@1/endpoint: Read of boolean property 'frame-master' with a value.
    [    4.273275] ffff00000a50c8c8 (lock_class){....}-{2:2}, at: __setup_irq+0xc4/0x690
    [    4.296130] renesas_sdhi_internal_dmac ee10000.mmc: mmc1 base at 0x00000000ee100000, max clock rate 200 MHz
    [    4.304082] stack backtrace:
    [    4.304086] CPU: 1 UID: 0 PID: 76 Comm: kworker/u8:5 Not tainted 6.13.0-rc7-arm64-renesas-05496-gd088502a519f torvalds#35
    [    4.304092] Hardware name: Renesas Salvator-X 2nd version board based on r8a77965 (DT)
    [    4.304097] Workqueue: async async_run_entry_fn
    [    4.304106] Call trace:
    [    4.304110]  show_stack+0x14/0x20 (C)
    [    4.304122]  dump_stack_lvl+0x6c/0x90
    [    4.304131]  dump_stack+0x14/0x1c
    [    4.304138]  __lock_acquire+0xdfc/0x1584
    [    4.426274]  lock_acquire+0x1c4/0x33c
    [    4.429942]  _raw_spin_lock_irqsave+0x5c/0x80
    [    4.434307]  gpio_rcar_config_interrupt_input_mode+0x34/0x164
    [    4.440061]  gpio_rcar_irq_set_type+0xd4/0xd8
    [    4.444422]  __irq_set_trigger+0x5c/0x178
    [    4.448435]  __setup_irq+0x2e4/0x690
    [    4.452012]  request_threaded_irq+0xc4/0x190
    [    4.456285]  devm_request_threaded_irq+0x7c/0xf4
    [    4.459398] ata1: link resume succeeded after 1 retries
    [    4.460902]  mmc_gpiod_request_cd_irq+0x68/0xe0
    [    4.470660]  mmc_start_host+0x50/0xac
    [    4.474327]  mmc_add_host+0x80/0xe4
    [    4.477817]  tmio_mmc_host_probe+0x2b0/0x440
    [    4.482094]  renesas_sdhi_probe+0x488/0x6f4
    [    4.486281]  renesas_sdhi_internal_dmac_probe+0x60/0x78
    [    4.491509]  platform_probe+0x64/0xd8
    [    4.495178]  really_probe+0xb8/0x2a8
    [    4.498756]  __driver_probe_device+0x74/0x118
    [    4.503116]  driver_probe_device+0x3c/0x154
    [    4.507303]  __device_attach_driver+0xd4/0x160
    [    4.511750]  bus_for_each_drv+0x84/0xe0
    [    4.515588]  __device_attach_async_helper+0xb0/0xdc
    [    4.520470]  async_run_entry_fn+0x30/0xd8
    [    4.524481]  process_one_work+0x210/0x62c
    [    4.528494]  worker_thread+0x1ac/0x340
    [    4.532245]  kthread+0x10c/0x110
    [    4.535476]  ret_from_fork+0x10/0x20

Signed-off-by: Niklas Söderlund <[email protected]>
Reviewed-by: Geert Uytterhoeven <[email protected]>
Tested-by: Geert Uytterhoeven <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Bartosz Golaszewski <[email protected]>
mpe pushed a commit that referenced this pull request Mar 16, 2025
…cal section

A circular lock dependency splat has been seen involving down_trylock():

  ======================================================
  WARNING: possible circular locking dependency detected
  6.12.0-41.el10.s390x+debug
  ------------------------------------------------------
  dd/32479 is trying to acquire lock:
  0015a20accd0d4f8 ((console_sem).lock){-.-.}-{2:2}, at: down_trylock+0x26/0x90

  but task is already holding lock:
  000000017e461698 (&zone->lock){-.-.}-{2:2}, at: rmqueue_bulk+0xac/0x8f0

  the existing dependency chain (in reverse order) is:
  -> #4 (&zone->lock){-.-.}-{2:2}:
  -> #3 (hrtimer_bases.lock){-.-.}-{2:2}:
  -> #2 (&rq->__lock){-.-.}-{2:2}:
  -> #1 (&p->pi_lock){-.-.}-{2:2}:
  -> #0 ((console_sem).lock){-.-.}-{2:2}:

The console_sem -> pi_lock dependency is due to calling try_to_wake_up()
while holding the console_sem raw_spinlock. This dependency can be broken
by using wake_q to do the wakeup instead of calling try_to_wake_up()
under the console_sem lock. This will also make the semaphore's
raw_spinlock become a terminal lock without taking any further locks
underneath it.

The hrtimer_bases.lock is a raw_spinlock while zone->lock is a
spinlock. The hrtimer_bases.lock -> zone->lock dependency happens via
the debug_objects_fill_pool() helper function in the debugobjects code.

  -> #4 (&zone->lock){-.-.}-{2:2}:
         __lock_acquire+0xe86/0x1cc0
         lock_acquire.part.0+0x258/0x630
         lock_acquire+0xb8/0xe0
         _raw_spin_lock_irqsave+0xb4/0x120
         rmqueue_bulk+0xac/0x8f0
         __rmqueue_pcplist+0x580/0x830
         rmqueue_pcplist+0xfc/0x470
         rmqueue.isra.0+0xdec/0x11b0
         get_page_from_freelist+0x2ee/0xeb0
         __alloc_pages_noprof+0x2c2/0x520
         alloc_pages_mpol_noprof+0x1fc/0x4d0
         alloc_pages_noprof+0x8c/0xe0
         allocate_slab+0x320/0x460
         ___slab_alloc+0xa58/0x12b0
         __slab_alloc.isra.0+0x42/0x60
         kmem_cache_alloc_noprof+0x304/0x350
         fill_pool+0xf6/0x450
         debug_object_activate+0xfe/0x360
         enqueue_hrtimer+0x34/0x190
         __run_hrtimer+0x3c8/0x4c0
         __hrtimer_run_queues+0x1b2/0x260
         hrtimer_interrupt+0x316/0x760
         do_IRQ+0x9a/0xe0
         do_irq_async+0xf6/0x160

Normally a raw_spinlock to spinlock dependency is not legitimate
and will be warned if CONFIG_PROVE_RAW_LOCK_NESTING is enabled,
but debug_objects_fill_pool() is an exception as it explicitly
allows this dependency for non-PREEMPT_RT kernel without causing
PROVE_RAW_LOCK_NESTING lockdep splat. As a result, this dependency is
legitimate and not a bug.

Anyway, semaphore is the only locking primitive left that is still
using try_to_wake_up() to do wakeup inside critical section, all the
other locking primitives had been migrated to use wake_q to do wakeup
outside of the critical section. It is also possible that there are
other circular locking dependencies involving printk/console_sem or
other existing/new semaphores lurking somewhere which may show up in
the future. Let just do the migration now to wake_q to avoid headache
like this.

Reported-by: [email protected]
Signed-off-by: Waiman Long <[email protected]>
Signed-off-by: Boqun Feng <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Cc: Linus Torvalds <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
mpe pushed a commit that referenced this pull request Mar 16, 2025
…/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 6.14, take #4

- Fix a couple of bugs affecting pKVM's PSCI relay implementation
  when running in the hVHE mode, resulting in the host being entered
  with the MMU in an unknown state, and EL2 being in the wrong mode.
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