Add sync module with a mutex implementation.
#102
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+1, and please copy-paste it into |
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Why Related: it might be a good idea to document why we require a type to be pinned or not (e.g. |
Yes, I'm adding
Sure, I'll add some text around this. |
I added a trivial example.
This is not very useful in |
It is useful because it is the only way we have to at least compile-test the macros and run at least the happy path once in the CI. If you are busy, that is fine, I can add it later myself :-) |
Fair enough. I've added some code there for this purpose, though it is not a useful sample of using mutexes. (Later on I'd like to add something like a counter of the number of bytes written, then |
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Folks, thank you for the reviews. I believe I addressed all the comments. I'd appreciate if you could have another look and let me know if you find anything else that could be improved. |
| //! This module contains the kernel APIs related to synchronisation that have been ported or | ||
| //! wrapped for usage by Rust code in the kernel and is shared by all of them. | ||
| //! | ||
| //! # Example |
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I'd move the example into mutex.rs, i.e. so that we have a different one for condvar, spinlock, etc.
Not sure if it is best to also move each of them to mutex_init!, rather than have them in the module doc, hmm... I will think about it, but we can move it later.
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If we move it to mutex.rs, would it be visible in the rendered docs? (Given that is gets 'exported' via pub use.)
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There is an attribute for pub use, to render the doc in place, so yes we can rerender it as it would be in this file.
| //! # Example | ||
| //! | ||
| //!``` | ||
| //! fn test() { |
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No need for wrapping into a fn test() { in examples, i.e. the code can go directly in "file" scope.
| //! This module contains the kernel APIs related to synchronisation that have been ported or | ||
| //! wrapped for usage by Rust code in the kernel and is shared by all of them. | ||
| //! | ||
| //! # Example |
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If we move it to mutex.rs, would it be visible in the rendered docs? (Given that is gets 'exported' via pub use.)
Commit a7259df ("memblock: make memblock_find_in_range method private") changed the API using which memory is reserved for the pKVM hypervisor. However, memblock_phys_alloc() differs from the original API in terms of kmemleak semantics -- the old one didn't report the reserved regions to kmemleak while the new one does. Unfortunately, when protected KVM is enabled, all kernel accesses to pKVM-private memory result in a fatal exception, which can now happen because of kmemleak scans: $ echo scan > /sys/kernel/debug/kmemleak [ 34.991354] kvm [304]: nVHE hyp BUG at: [<ffff800008fa3750>] __kvm_nvhe_handle_host_mem_abort+0x270/0x290! [ 34.991580] kvm [304]: Hyp Offset: 0xfffe8be807e00000 [ 34.991813] Kernel panic - not syncing: HYP panic: [ 34.991813] PS:600003c9 PC:0000f418011a3750 ESR:00000000f2000800 [ 34.991813] FAR:ffff000439200000 HPFAR:0000000004792000 PAR:0000000000000000 [ 34.991813] VCPU:0000000000000000 [ 34.993660] CPU: 0 PID: 304 Comm: bash Not tainted 5.19.0-rc2 #102 [ 34.994059] Hardware name: linux,dummy-virt (DT) [ 34.994452] Call trace: [ 34.994641] dump_backtrace.part.0+0xcc/0xe0 [ 34.994932] show_stack+0x18/0x6c [ 34.995094] dump_stack_lvl+0x68/0x84 [ 34.995276] dump_stack+0x18/0x34 [ 34.995484] panic+0x16c/0x354 [ 34.995673] __hyp_pgtable_total_pages+0x0/0x60 [ 34.995933] scan_block+0x74/0x12c [ 34.996129] scan_gray_list+0xd8/0x19c [ 34.996332] kmemleak_scan+0x2c8/0x580 [ 34.996535] kmemleak_write+0x340/0x4a0 [ 34.996744] full_proxy_write+0x60/0xbc [ 34.996967] vfs_write+0xc4/0x2b0 [ 34.997136] ksys_write+0x68/0xf4 [ 34.997311] __arm64_sys_write+0x20/0x2c [ 34.997532] invoke_syscall+0x48/0x114 [ 34.997779] el0_svc_common.constprop.0+0x44/0xec [ 34.998029] do_el0_svc+0x2c/0xc0 [ 34.998205] el0_svc+0x2c/0x84 [ 34.998421] el0t_64_sync_handler+0xf4/0x100 [ 34.998653] el0t_64_sync+0x18c/0x190 [ 34.999252] SMP: stopping secondary CPUs [ 35.000034] Kernel Offset: disabled [ 35.000261] CPU features: 0x800,00007831,00001086 [ 35.000642] Memory Limit: none [ 35.001329] ---[ end Kernel panic - not syncing: HYP panic: [ 35.001329] PS:600003c9 PC:0000f418011a3750 ESR:00000000f2000800 [ 35.001329] FAR:ffff000439200000 HPFAR:0000000004792000 PAR:0000000000000000 [ 35.001329] VCPU:0000000000000000 ]--- Fix this by explicitly excluding the hypervisor's memory pool from kmemleak like we already do for the hyp BSS. Cc: Mike Rapoport <[email protected]> Fixes: a7259df ("memblock: make memblock_find_in_range method private") Signed-off-by: Quentin Perret <[email protected]> Acked-by: Catalin Marinas <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Link: https://lore.kernel.org/r/[email protected]
After this patch: Rust-for-Linux#102/1 flow_dissector_classification/ipv4:OK Rust-for-Linux#102/2 flow_dissector_classification/ipv4_continue_dissect:OK Rust-for-Linux#102/3 flow_dissector_classification/ipip:OK Rust-for-Linux#102/4 flow_dissector_classification/gre:OK Rust-for-Linux#102/5 flow_dissector_classification/port_range:OK Rust-for-Linux#102/6 flow_dissector_classification/ipv6:OK Rust-for-Linux#102 flow_dissector_classification:OK Summary: 1/6 PASSED, 0 SKIPPED, 0 FAILED Cc: Daniel Borkmann <[email protected]> Cc: Andrii Nakryiko <[email protected]> Signed-off-by: Cong Wang <[email protected]> Link: https://patch.msgid.link/[email protected] Signed-off-by: Jakub Kicinski <[email protected]>
When MPOA_cache_impos_rcvd() receives the msg, it can trigger Null Pointer Dereference Vulnerability if both entry and holding_time are NULL. Because there is only for the situation where entry is NULL and holding_time exists, it can be passed when both entry and holding_time are NULL. If these are NULL, the entry will be passd to eg_cache_put() as parameter and it is referenced by entry->use code in it. kasan log: [ 3.316691] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006:I [ 3.317568] KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037] [ 3.318188] CPU: 3 UID: 0 PID: 79 Comm: ex Not tainted 6.14.0-rc2 #102 [ 3.318601] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 [ 3.319298] RIP: 0010:eg_cache_remove_entry+0xa5/0x470 [ 3.319677] Code: c1 f7 6e fd 48 c7 c7 00 7e 38 b2 e8 95 64 54 fd 48 c7 c7 40 7e 38 b2 48 89 ee e80 [ 3.321220] RSP: 0018:ffff88800583f8a8 EFLAGS: 00010006 [ 3.321596] RAX: 0000000000000006 RBX: ffff888005989000 RCX: ffffffffaecc2d8e [ 3.322112] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000030 [ 3.322643] RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff6558b88 [ 3.323181] R10: 0000000000000003 R11: 203a207972746e65 R12: 1ffff11000b07f15 [ 3.323707] R13: dffffc0000000000 R14: ffff888005989000 R15: ffff888005989068 [ 3.324185] FS: 000000001b6313c0(0000) GS:ffff88806d380000(0000) knlGS:0000000000000000 [ 3.325042] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 3.325545] CR2: 00000000004b4b40 CR3: 000000000248e000 CR4: 00000000000006f0 [ 3.326430] Call Trace: [ 3.326725] <TASK> [ 3.326927] ? die_addr+0x3c/0xa0 [ 3.327330] ? exc_general_protection+0x161/0x2a0 [ 3.327662] ? asm_exc_general_protection+0x26/0x30 [ 3.328214] ? vprintk_emit+0x15e/0x420 [ 3.328543] ? eg_cache_remove_entry+0xa5/0x470 [ 3.328910] ? eg_cache_remove_entry+0x9a/0x470 [ 3.329294] ? __pfx_eg_cache_remove_entry+0x10/0x10 [ 3.329664] ? console_unlock+0x107/0x1d0 [ 3.329946] ? __pfx_console_unlock+0x10/0x10 [ 3.330283] ? do_syscall_64+0xa6/0x1a0 [ 3.330584] ? entry_SYSCALL_64_after_hwframe+0x47/0x7f [ 3.331090] ? __pfx_prb_read_valid+0x10/0x10 [ 3.331395] ? down_trylock+0x52/0x80 [ 3.331703] ? vprintk_emit+0x15e/0x420 [ 3.331986] ? __pfx_vprintk_emit+0x10/0x10 [ 3.332279] ? down_trylock+0x52/0x80 [ 3.332527] ? _printk+0xbf/0x100 [ 3.332762] ? __pfx__printk+0x10/0x10 [ 3.333007] ? _raw_write_lock_irq+0x81/0xe0 [ 3.333284] ? __pfx__raw_write_lock_irq+0x10/0x10 [ 3.333614] msg_from_mpoad+0x1185/0x2750 [ 3.333893] ? __build_skb_around+0x27b/0x3a0 [ 3.334183] ? __pfx_msg_from_mpoad+0x10/0x10 [ 3.334501] ? __alloc_skb+0x1c0/0x310 [ 3.334809] ? __pfx___alloc_skb+0x10/0x10 [ 3.335283] ? _raw_spin_lock+0xe0/0xe0 [ 3.335632] ? finish_wait+0x8d/0x1e0 [ 3.335975] vcc_sendmsg+0x684/0xba0 [ 3.336250] ? __pfx_vcc_sendmsg+0x10/0x10 [ 3.336587] ? __pfx_autoremove_wake_function+0x10/0x10 [ 3.337056] ? fdget+0x176/0x3e0 [ 3.337348] __sys_sendto+0x4a2/0x510 [ 3.337663] ? __pfx___sys_sendto+0x10/0x10 [ 3.337969] ? ioctl_has_perm.constprop.0.isra.0+0x284/0x400 [ 3.338364] ? sock_ioctl+0x1bb/0x5a0 [ 3.338653] ? __rseq_handle_notify_resume+0x825/0xd20 [ 3.339017] ? __pfx_sock_ioctl+0x10/0x10 [ 3.339316] ? __pfx___rseq_handle_notify_resume+0x10/0x10 [ 3.339727] ? selinux_file_ioctl+0xa4/0x260 [ 3.340166] __x64_sys_sendto+0xe0/0x1c0 [ 3.340526] ? syscall_exit_to_user_mode+0x123/0x140 [ 3.340898] do_syscall_64+0xa6/0x1a0 [ 3.341170] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 3.341533] RIP: 0033:0x44a380 [ 3.341757] Code: 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 41 89 ca 64 8b 04 25 18 00 00 00 85 c00 [ 3.343078] RSP: 002b:00007ffc1d404098 EFLAGS: 00000246 ORIG_RAX: 000000000000002c [ 3.343631] RAX: ffffffffffffffda RBX: 00007ffc1d404458 RCX: 000000000044a380 [ 3.344306] RDX: 000000000000019c RSI: 00007ffc1d4040b0 RDI: 0000000000000003 [ 3.344833] RBP: 00007ffc1d404260 R08: 0000000000000000 R09: 0000000000000000 [ 3.345381] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [ 3.346015] R13: 00007ffc1d404448 R14: 00000000004c17d0 R15: 0000000000000001 [ 3.346503] </TASK> [ 3.346679] Modules linked in: [ 3.346956] ---[ end trace 0000000000000000 ]--- [ 3.347315] RIP: 0010:eg_cache_remove_entry+0xa5/0x470 [ 3.347737] Code: c1 f7 6e fd 48 c7 c7 00 7e 38 b2 e8 95 64 54 fd 48 c7 c7 40 7e 38 b2 48 89 ee e80 [ 3.349157] RSP: 0018:ffff88800583f8a8 EFLAGS: 00010006 [ 3.349517] RAX: 0000000000000006 RBX: ffff888005989000 RCX: ffffffffaecc2d8e [ 3.350103] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000030 [ 3.350610] RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff6558b88 [ 3.351246] R10: 0000000000000003 R11: 203a207972746e65 R12: 1ffff11000b07f15 [ 3.351785] R13: dffffc0000000000 R14: ffff888005989000 R15: ffff888005989068 [ 3.352404] FS: 000000001b6313c0(0000) GS:ffff88806d380000(0000) knlGS:0000000000000000 [ 3.353099] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 3.353544] CR2: 00000000004b4b40 CR3: 000000000248e000 CR4: 00000000000006f0 [ 3.354072] note: ex[79] exited with irqs disabled [ 3.354458] note: ex[79] exited with preempt_count 1 Signed-off-by: Minjoong Kim <[email protected]> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reviewed-by: Simon Horman <[email protected]> Link: https://patch.msgid.link/[email protected] Signed-off-by: Jakub Kicinski <[email protected]>
This introduces a
syncmodule with a mutex implementation. In the next couple of days I'll send pull requests for spinlocks, condvars, and locked_by. These are all used in the driver: I'm planning to submit all rust/ changes before the driver.