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@madaidan madaidan commented Aug 2, 2019

This makes it harder to load a malicious kernel module by requiring them to be signed with a valid key. Any module that is unsigned or signed with an invalid key won't be loaded.

https://www.kernel.org/doc/html/v5.2/admin-guide/module-signing.html

@Bernhard40
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This will require all out-of-tree modules like nvidia drivers or wireguard have to be signed with the same key which was used for building kernel which isn't feasible except for private use therefore this option shouldn't be the default. I recommend to use boot param instead.

@madaidan
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madaidan commented Aug 3, 2019

I forgot about those. This isn't a good idea then. Thanks.

@madaidan madaidan closed this Aug 3, 2019
anthraxx pushed a commit that referenced this pull request Aug 17, 2019
commit d0a255e upstream.

A deadlock with this stacktrace was observed.

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

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

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

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

Signed-off-by: Mikulas Patocka <[email protected]>
Cc: [email protected]
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx pushed a commit that referenced this pull request Aug 17, 2019
commit d0a255e upstream.

A deadlock with this stacktrace was observed.

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

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

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

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

Signed-off-by: Mikulas Patocka <[email protected]>
Cc: [email protected]
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx pushed a commit that referenced this pull request Aug 17, 2019
commit d0a255e upstream.

A deadlock with this stacktrace was observed.

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

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

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

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

Signed-off-by: Mikulas Patocka <[email protected]>
Cc: [email protected]
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx pushed a commit that referenced this pull request Sep 2, 2019
commit cf3591e upstream.

Revert the commit bd293d0. The proper
fix has been made available with commit d0a255e ("loop: set
PF_MEMALLOC_NOIO for the worker thread").

Note that the fix offered by commit bd293d0 doesn't really prevent
the deadlock from occuring - if we look at the stacktrace reported by
Junxiao Bi, we see that it hangs in bit_wait_io and not on the mutex -
i.e. it has already successfully taken the mutex. Changing the mutex
from mutex_lock to mutex_trylock won't help with deadlocks that happen
afterwards.

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

Signed-off-by: Mikulas Patocka <[email protected]>
Cc: [email protected]
Fixes: bd293d0 ("dm bufio: fix deadlock with loop device")
Depends-on: d0a255e ("loop: set PF_MEMALLOC_NOIO for the worker thread")
Signed-off-by: Mike Snitzer <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx pushed a commit that referenced this pull request Sep 2, 2019
commit cf3591e upstream.

Revert the commit bd293d0. The proper
fix has been made available with commit d0a255e ("loop: set
PF_MEMALLOC_NOIO for the worker thread").

Note that the fix offered by commit bd293d0 doesn't really prevent
the deadlock from occuring - if we look at the stacktrace reported by
Junxiao Bi, we see that it hangs in bit_wait_io and not on the mutex -
i.e. it has already successfully taken the mutex. Changing the mutex
from mutex_lock to mutex_trylock won't help with deadlocks that happen
afterwards.

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

Signed-off-by: Mikulas Patocka <[email protected]>
Cc: [email protected]
Fixes: bd293d0 ("dm bufio: fix deadlock with loop device")
Depends-on: d0a255e ("loop: set PF_MEMALLOC_NOIO for the worker thread")
Signed-off-by: Mike Snitzer <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx pushed a commit that referenced this pull request Sep 2, 2019
commit cf3591e upstream.

Revert the commit bd293d0. The proper
fix has been made available with commit d0a255e ("loop: set
PF_MEMALLOC_NOIO for the worker thread").

Note that the fix offered by commit bd293d0 doesn't really prevent
the deadlock from occuring - if we look at the stacktrace reported by
Junxiao Bi, we see that it hangs in bit_wait_io and not on the mutex -
i.e. it has already successfully taken the mutex. Changing the mutex
from mutex_lock to mutex_trylock won't help with deadlocks that happen
afterwards.

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

Signed-off-by: Mikulas Patocka <[email protected]>
Cc: [email protected]
Fixes: bd293d0 ("dm bufio: fix deadlock with loop device")
Depends-on: d0a255e ("loop: set PF_MEMALLOC_NOIO for the worker thread")
Signed-off-by: Mike Snitzer <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx pushed a commit that referenced this pull request Oct 7, 2019
[ Upstream commit 76e43c8 ]

When IOCB_CMD_POLL is used on the FUSE device, aio_poll() disables IRQs
and takes kioctx::ctx_lock, then fuse_iqueue::waitq.lock.

This may have to wait for fuse_iqueue::waitq.lock to be released by one
of many places that take it with IRQs enabled.  Since the IRQ handler
may take kioctx::ctx_lock, lockdep reports that a deadlock is possible.

Fix it by protecting the state of struct fuse_iqueue with a separate
spinlock, and only accessing fuse_iqueue::waitq using the versions of
the waitqueue functions which do IRQ-safe locking internally.

Reproducer:

	#include <fcntl.h>
	#include <stdio.h>
	#include <sys/mount.h>
	#include <sys/stat.h>
	#include <sys/syscall.h>
	#include <unistd.h>
	#include <linux/aio_abi.h>

	int main()
	{
		char opts[128];
		int fd = open("/dev/fuse", O_RDWR);
		aio_context_t ctx = 0;
		struct iocb cb = { .aio_lio_opcode = IOCB_CMD_POLL, .aio_fildes = fd };
		struct iocb *cbp = &cb;

		sprintf(opts, "fd=%d,rootmode=040000,user_id=0,group_id=0", fd);
		mkdir("mnt", 0700);
		mount("foo",  "mnt", "fuse", 0, opts);
		syscall(__NR_io_setup, 1, &ctx);
		syscall(__NR_io_submit, ctx, 1, &cbp);
	}

Beginning of lockdep output:

	=====================================================
	WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
	5.3.0-rc5 #9 Not tainted
	-----------------------------------------------------
	syz_fuse/135 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
	000000003590ceda (&fiq->waitq){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline]
	000000003590ceda (&fiq->waitq){+.+.}, at: aio_poll fs/aio.c:1751 [inline]
	000000003590ceda (&fiq->waitq){+.+.}, at: __io_submit_one.constprop.0+0x203/0x5b0 fs/aio.c:1825

	and this task is already holding:
	0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: spin_lock_irq include/linux/spinlock.h:363 [inline]
	0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: aio_poll fs/aio.c:1749 [inline]
	0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: __io_submit_one.constprop.0+0x1f4/0x5b0 fs/aio.c:1825
	which would create a new lock dependency:
	 (&(&ctx->ctx_lock)->rlock){..-.} -> (&fiq->waitq){+.+.}

	but this new dependency connects a SOFTIRQ-irq-safe lock:
	 (&(&ctx->ctx_lock)->rlock){..-.}

	[...]

Reported-by: [email protected]
Reported-by: [email protected]
Fixes: bfe4037 ("aio: implement IOCB_CMD_POLL")
Cc: <[email protected]> # v4.19+
Cc: Christoph Hellwig <[email protected]>
Signed-off-by: Eric Biggers <[email protected]>
Signed-off-by: Miklos Szeredi <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx pushed a commit that referenced this pull request Oct 7, 2019
…perations

[ Upstream commit 62fdaa5 ]

[BUG]
With crafted image, btrfs will panic at btree operations:

  kernel BUG at fs/btrfs/ctree.c:3894!
  invalid opcode: 0000 [#1] SMP PTI
  CPU: 0 PID: 1138 Comm: btrfs-transacti Not tainted 5.0.0-rc8+ #9
  RIP: 0010:__push_leaf_left+0x6b6/0x6e0
  RSP: 0018:ffffc0bd4128b990 EFLAGS: 00010246
  RAX: 0000000000000000 RBX: ffffa0a4ab8f0e38 RCX: 0000000000000000
  RDX: ffffa0a280000000 RSI: 0000000000000000 RDI: ffffa0a4b3814000
  RBP: ffffc0bd4128ba38 R08: 0000000000001000 R09: ffffc0bd4128b948
  R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000240
  R13: ffffa0a4b556fb60 R14: ffffa0a4ab8f0af0 R15: ffffa0a4ab8f0af0
  FS: 0000000000000000(0000) GS:ffffa0a4b7a00000(0000) knlGS:0000000000000000
  CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f2461c80020 CR3: 000000022b32a006 CR4: 00000000000206f0
  Call Trace:
  ? _cond_resched+0x1a/0x50
  push_leaf_left+0x179/0x190
  btrfs_del_items+0x316/0x470
  btrfs_del_csums+0x215/0x3a0
  __btrfs_free_extent.isra.72+0x5a7/0xbe0
  __btrfs_run_delayed_refs+0x539/0x1120
  btrfs_run_delayed_refs+0xdb/0x1b0
  btrfs_commit_transaction+0x52/0x950
  ? start_transaction+0x94/0x450
  transaction_kthread+0x163/0x190
  kthread+0x105/0x140
  ? btrfs_cleanup_transaction+0x560/0x560
  ? kthread_destroy_worker+0x50/0x50
  ret_from_fork+0x35/0x40
  Modules linked in:
  ---[ end trace c2425e6e89b5558f ]---

[CAUSE]
The offending csum tree looks like this:

  checksum tree key (CSUM_TREE ROOT_ITEM 0)
  node 29741056 level 1 items 14 free 107 generation 19 owner CSUM_TREE
	  ...
	  key (EXTENT_CSUM EXTENT_CSUM 85975040) block 29630464 gen 17
	  key (EXTENT_CSUM EXTENT_CSUM 89911296) block 29642752 gen 17 <<<
	  key (EXTENT_CSUM EXTENT_CSUM 92274688) block 29646848 gen 17
	  ...

  leaf 29630464 items 6 free space 1 generation 17 owner CSUM_TREE
	  item 0 key (EXTENT_CSUM EXTENT_CSUM 85975040) itemoff 3987 itemsize 8
		  range start 85975040 end 85983232 length 8192
	  ...
  leaf 29642752 items 0 free space 3995 generation 17 owner 0
		      ^ empty leaf            invalid owner ^

  leaf 29646848 items 1 free space 602 generation 17 owner CSUM_TREE
	  item 0 key (EXTENT_CSUM EXTENT_CSUM 92274688) itemoff 627 itemsize 3368
		  range start 92274688 end 95723520 length 3448832

So we have a corrupted csum tree where one tree leaf is completely
empty, causing unbalanced btree, thus leading to unexpected btree
balance error.

[FIX]
For this particular case, we handle it in two directions to catch it:
- Check if the tree block is empty through btrfs_verify_level_key()
  So that invalid tree blocks won't be read out through
  btrfs_search_slot() and its variants.

- Check 0 tree owner in tree checker
  NO tree is using 0 as its tree owner, detect it and reject at tree
  block read time.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202821
Reviewed-by: Nikolay Borisov <[email protected]>
Signed-off-by: Qu Wenruo <[email protected]>
Signed-off-by: David Sterba <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Oct 7, 2019
commit 76e43c8 upstream.

When IOCB_CMD_POLL is used on the FUSE device, aio_poll() disables IRQs
and takes kioctx::ctx_lock, then fuse_iqueue::waitq.lock.

This may have to wait for fuse_iqueue::waitq.lock to be released by one
of many places that take it with IRQs enabled.  Since the IRQ handler
may take kioctx::ctx_lock, lockdep reports that a deadlock is possible.

Fix it by protecting the state of struct fuse_iqueue with a separate
spinlock, and only accessing fuse_iqueue::waitq using the versions of
the waitqueue functions which do IRQ-safe locking internally.

Reproducer:

	#include <fcntl.h>
	#include <stdio.h>
	#include <sys/mount.h>
	#include <sys/stat.h>
	#include <sys/syscall.h>
	#include <unistd.h>
	#include <linux/aio_abi.h>

	int main()
	{
		char opts[128];
		int fd = open("/dev/fuse", O_RDWR);
		aio_context_t ctx = 0;
		struct iocb cb = { .aio_lio_opcode = IOCB_CMD_POLL, .aio_fildes = fd };
		struct iocb *cbp = &cb;

		sprintf(opts, "fd=%d,rootmode=040000,user_id=0,group_id=0", fd);
		mkdir("mnt", 0700);
		mount("foo",  "mnt", "fuse", 0, opts);
		syscall(__NR_io_setup, 1, &ctx);
		syscall(__NR_io_submit, ctx, 1, &cbp);
	}

Beginning of lockdep output:

	=====================================================
	WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
	5.3.0-rc5 #9 Not tainted
	-----------------------------------------------------
	syz_fuse/135 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
	000000003590ceda (&fiq->waitq){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline]
	000000003590ceda (&fiq->waitq){+.+.}, at: aio_poll fs/aio.c:1751 [inline]
	000000003590ceda (&fiq->waitq){+.+.}, at: __io_submit_one.constprop.0+0x203/0x5b0 fs/aio.c:1825

	and this task is already holding:
	0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: spin_lock_irq include/linux/spinlock.h:363 [inline]
	0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: aio_poll fs/aio.c:1749 [inline]
	0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: __io_submit_one.constprop.0+0x1f4/0x5b0 fs/aio.c:1825
	which would create a new lock dependency:
	 (&(&ctx->ctx_lock)->rlock){..-.} -> (&fiq->waitq){+.+.}

	but this new dependency connects a SOFTIRQ-irq-safe lock:
	 (&(&ctx->ctx_lock)->rlock){..-.}

	[...]

Reported-by: [email protected]
Reported-by: [email protected]
Fixes: bfe4037 ("aio: implement IOCB_CMD_POLL")
Cc: <[email protected]> # v4.19+
Cc: Christoph Hellwig <[email protected]>
Signed-off-by: Eric Biggers <[email protected]>
Signed-off-by: Miklos Szeredi <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx pushed a commit that referenced this pull request Oct 17, 2019
…perations

[ Upstream commit 62fdaa5 ]

[BUG]
With crafted image, btrfs will panic at btree operations:

  kernel BUG at fs/btrfs/ctree.c:3894!
  invalid opcode: 0000 [#1] SMP PTI
  CPU: 0 PID: 1138 Comm: btrfs-transacti Not tainted 5.0.0-rc8+ #9
  RIP: 0010:__push_leaf_left+0x6b6/0x6e0
  RSP: 0018:ffffc0bd4128b990 EFLAGS: 00010246
  RAX: 0000000000000000 RBX: ffffa0a4ab8f0e38 RCX: 0000000000000000
  RDX: ffffa0a280000000 RSI: 0000000000000000 RDI: ffffa0a4b3814000
  RBP: ffffc0bd4128ba38 R08: 0000000000001000 R09: ffffc0bd4128b948
  R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000240
  R13: ffffa0a4b556fb60 R14: ffffa0a4ab8f0af0 R15: ffffa0a4ab8f0af0
  FS: 0000000000000000(0000) GS:ffffa0a4b7a00000(0000) knlGS:0000000000000000
  CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f2461c80020 CR3: 000000022b32a006 CR4: 00000000000206f0
  Call Trace:
  ? _cond_resched+0x1a/0x50
  push_leaf_left+0x179/0x190
  btrfs_del_items+0x316/0x470
  btrfs_del_csums+0x215/0x3a0
  __btrfs_free_extent.isra.72+0x5a7/0xbe0
  __btrfs_run_delayed_refs+0x539/0x1120
  btrfs_run_delayed_refs+0xdb/0x1b0
  btrfs_commit_transaction+0x52/0x950
  ? start_transaction+0x94/0x450
  transaction_kthread+0x163/0x190
  kthread+0x105/0x140
  ? btrfs_cleanup_transaction+0x560/0x560
  ? kthread_destroy_worker+0x50/0x50
  ret_from_fork+0x35/0x40
  Modules linked in:
  ---[ end trace c2425e6e89b5558f ]---

[CAUSE]
The offending csum tree looks like this:

  checksum tree key (CSUM_TREE ROOT_ITEM 0)
  node 29741056 level 1 items 14 free 107 generation 19 owner CSUM_TREE
	  ...
	  key (EXTENT_CSUM EXTENT_CSUM 85975040) block 29630464 gen 17
	  key (EXTENT_CSUM EXTENT_CSUM 89911296) block 29642752 gen 17 <<<
	  key (EXTENT_CSUM EXTENT_CSUM 92274688) block 29646848 gen 17
	  ...

  leaf 29630464 items 6 free space 1 generation 17 owner CSUM_TREE
	  item 0 key (EXTENT_CSUM EXTENT_CSUM 85975040) itemoff 3987 itemsize 8
		  range start 85975040 end 85983232 length 8192
	  ...
  leaf 29642752 items 0 free space 3995 generation 17 owner 0
		      ^ empty leaf            invalid owner ^

  leaf 29646848 items 1 free space 602 generation 17 owner CSUM_TREE
	  item 0 key (EXTENT_CSUM EXTENT_CSUM 92274688) itemoff 627 itemsize 3368
		  range start 92274688 end 95723520 length 3448832

So we have a corrupted csum tree where one tree leaf is completely
empty, causing unbalanced btree, thus leading to unexpected btree
balance error.

[FIX]
For this particular case, we handle it in two directions to catch it:
- Check if the tree block is empty through btrfs_verify_level_key()
  So that invalid tree blocks won't be read out through
  btrfs_search_slot() and its variants.

- Check 0 tree owner in tree checker
  NO tree is using 0 as its tree owner, detect it and reject at tree
  block read time.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202821
Reviewed-by: Nikolay Borisov <[email protected]>
Signed-off-by: Qu Wenruo <[email protected]>
Signed-off-by: David Sterba <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Oct 17, 2019
commit 76e43c8 upstream.

When IOCB_CMD_POLL is used on the FUSE device, aio_poll() disables IRQs
and takes kioctx::ctx_lock, then fuse_iqueue::waitq.lock.

This may have to wait for fuse_iqueue::waitq.lock to be released by one
of many places that take it with IRQs enabled.  Since the IRQ handler
may take kioctx::ctx_lock, lockdep reports that a deadlock is possible.

Fix it by protecting the state of struct fuse_iqueue with a separate
spinlock, and only accessing fuse_iqueue::waitq using the versions of
the waitqueue functions which do IRQ-safe locking internally.

Reproducer:

	#include <fcntl.h>
	#include <stdio.h>
	#include <sys/mount.h>
	#include <sys/stat.h>
	#include <sys/syscall.h>
	#include <unistd.h>
	#include <linux/aio_abi.h>

	int main()
	{
		char opts[128];
		int fd = open("/dev/fuse", O_RDWR);
		aio_context_t ctx = 0;
		struct iocb cb = { .aio_lio_opcode = IOCB_CMD_POLL, .aio_fildes = fd };
		struct iocb *cbp = &cb;

		sprintf(opts, "fd=%d,rootmode=040000,user_id=0,group_id=0", fd);
		mkdir("mnt", 0700);
		mount("foo",  "mnt", "fuse", 0, opts);
		syscall(__NR_io_setup, 1, &ctx);
		syscall(__NR_io_submit, ctx, 1, &cbp);
	}

Beginning of lockdep output:

	=====================================================
	WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
	5.3.0-rc5 #9 Not tainted
	-----------------------------------------------------
	syz_fuse/135 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
	000000003590ceda (&fiq->waitq){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline]
	000000003590ceda (&fiq->waitq){+.+.}, at: aio_poll fs/aio.c:1751 [inline]
	000000003590ceda (&fiq->waitq){+.+.}, at: __io_submit_one.constprop.0+0x203/0x5b0 fs/aio.c:1825

	and this task is already holding:
	0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: spin_lock_irq include/linux/spinlock.h:363 [inline]
	0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: aio_poll fs/aio.c:1749 [inline]
	0000000075037284 (&(&ctx->ctx_lock)->rlock){..-.}, at: __io_submit_one.constprop.0+0x1f4/0x5b0 fs/aio.c:1825
	which would create a new lock dependency:
	 (&(&ctx->ctx_lock)->rlock){..-.} -> (&fiq->waitq){+.+.}

	but this new dependency connects a SOFTIRQ-irq-safe lock:
	 (&(&ctx->ctx_lock)->rlock){..-.}

	[...]

Reported-by: [email protected]
Reported-by: [email protected]
Fixes: bfe4037 ("aio: implement IOCB_CMD_POLL")
Cc: <[email protected]> # v4.19+
Cc: Christoph Hellwig <[email protected]>
Signed-off-by: Eric Biggers <[email protected]>
Signed-off-by: Miklos Szeredi <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx pushed a commit that referenced this pull request Jan 2, 2020
…_clear_bit

[ Upstream commit fadcbd2 ]

We need to move "spin_lock_irq(&bitmap->counts.lock)" before unmap previous
storage, otherwise panic like belows could happen as follows.

[  902.353802] sdl: detected capacity change from 1077936128 to 3221225472
[  902.616948] general protection fault: 0000 [#1] SMP
[snip]
[  902.618588] CPU: 12 PID: 33698 Comm: md0_raid1 Tainted: G           O    4.14.144-1-pserver #4.14.144-1.1~deb10
[  902.618870] Hardware name: Supermicro SBA-7142G-T4/BHQGE, BIOS 3.00       10/24/2012
[  902.619120] task: ffff9ae1860fc600 task.stack: ffffb52e4c704000
[  902.619301] RIP: 0010:bitmap_file_clear_bit+0x90/0xd0 [md_mod]
[  902.619464] RSP: 0018:ffffb52e4c707d28 EFLAGS: 00010087
[  902.619626] RAX: ffe8008b0d061000 RBX: ffff9ad078c87300 RCX: 0000000000000000
[  902.619792] RDX: ffff9ad986341868 RSI: 0000000000000803 RDI: ffff9ad078c87300
[  902.619986] RBP: ffff9ad0ed7a8000 R08: 0000000000000000 R09: 0000000000000000
[  902.620154] R10: ffffb52e4c707ec0 R11: ffff9ad987d1ed44 R12: ffff9ad0ed7a8360
[  902.620320] R13: 0000000000000003 R14: 0000000000060000 R15: 0000000000000800
[  902.620487] FS:  0000000000000000(0000) GS:ffff9ad987d00000(0000) knlGS:0000000000000000
[  902.620738] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  902.620901] CR2: 000055ff12aecec0 CR3: 0000001005207000 CR4: 00000000000406e0
[  902.621068] Call Trace:
[  902.621256]  bitmap_daemon_work+0x2dd/0x360 [md_mod]
[  902.621429]  ? find_pers+0x70/0x70 [md_mod]
[  902.621597]  md_check_recovery+0x51/0x540 [md_mod]
[  902.621762]  raid1d+0x5c/0xeb0 [raid1]
[  902.621939]  ? try_to_del_timer_sync+0x4d/0x80
[  902.622102]  ? del_timer_sync+0x35/0x40
[  902.622265]  ? schedule_timeout+0x177/0x360
[  902.622453]  ? call_timer_fn+0x130/0x130
[  902.622623]  ? find_pers+0x70/0x70 [md_mod]
[  902.622794]  ? md_thread+0x94/0x150 [md_mod]
[  902.622959]  md_thread+0x94/0x150 [md_mod]
[  902.623121]  ? wait_woken+0x80/0x80
[  902.623280]  kthread+0x119/0x130
[  902.623437]  ? kthread_create_on_node+0x60/0x60
[  902.623600]  ret_from_fork+0x22/0x40
[  902.624225] RIP: bitmap_file_clear_bit+0x90/0xd0 [md_mod] RSP: ffffb52e4c707d28

Because mdadm was running on another cpu to do resize, so bitmap_resize was
called to replace bitmap as below shows.

PID: 38801  TASK: ffff9ad074a90e00  CPU: 0   COMMAND: "mdadm"
   [exception RIP: queued_spin_lock_slowpath+56]
   [snip]
-- <NMI exception stack> --
 #5 [ffffb52e60f17c58] queued_spin_lock_slowpath at ffffffff9c0b27b8
 #6 [ffffb52e60f17c58] bitmap_resize at ffffffffc0399877 [md_mod]
 #7 [ffffb52e60f17d30] raid1_resize at ffffffffc0285bf9 [raid1]
 #8 [ffffb52e60f17d50] update_size at ffffffffc038a31a [md_mod]
 #9 [ffffb52e60f17d70] md_ioctl at ffffffffc0395ca4 [md_mod]

And the procedure to keep resize bitmap safe is allocate new storage
space, then quiesce, copy bits, replace bitmap, and re-start.

However the daemon (bitmap_daemon_work) could happen even the array is
quiesced, which means when bitmap_file_clear_bit is triggered by raid1d,
then it thinks it should be fine to access store->filemap since
counts->lock is held, but resize could change the storage without the
protection of the lock.

Cc: Jack Wang <[email protected]>
Cc: NeilBrown <[email protected]>
Signed-off-by: Guoqing Jiang <[email protected]>
Signed-off-by: Song Liu <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jan 2, 2020
…_clear_bit

[ Upstream commit fadcbd2 ]

We need to move "spin_lock_irq(&bitmap->counts.lock)" before unmap previous
storage, otherwise panic like belows could happen as follows.

[  902.353802] sdl: detected capacity change from 1077936128 to 3221225472
[  902.616948] general protection fault: 0000 [#1] SMP
[snip]
[  902.618588] CPU: 12 PID: 33698 Comm: md0_raid1 Tainted: G           O    4.14.144-1-pserver #4.14.144-1.1~deb10
[  902.618870] Hardware name: Supermicro SBA-7142G-T4/BHQGE, BIOS 3.00       10/24/2012
[  902.619120] task: ffff9ae1860fc600 task.stack: ffffb52e4c704000
[  902.619301] RIP: 0010:bitmap_file_clear_bit+0x90/0xd0 [md_mod]
[  902.619464] RSP: 0018:ffffb52e4c707d28 EFLAGS: 00010087
[  902.619626] RAX: ffe8008b0d061000 RBX: ffff9ad078c87300 RCX: 0000000000000000
[  902.619792] RDX: ffff9ad986341868 RSI: 0000000000000803 RDI: ffff9ad078c87300
[  902.619986] RBP: ffff9ad0ed7a8000 R08: 0000000000000000 R09: 0000000000000000
[  902.620154] R10: ffffb52e4c707ec0 R11: ffff9ad987d1ed44 R12: ffff9ad0ed7a8360
[  902.620320] R13: 0000000000000003 R14: 0000000000060000 R15: 0000000000000800
[  902.620487] FS:  0000000000000000(0000) GS:ffff9ad987d00000(0000) knlGS:0000000000000000
[  902.620738] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  902.620901] CR2: 000055ff12aecec0 CR3: 0000001005207000 CR4: 00000000000406e0
[  902.621068] Call Trace:
[  902.621256]  bitmap_daemon_work+0x2dd/0x360 [md_mod]
[  902.621429]  ? find_pers+0x70/0x70 [md_mod]
[  902.621597]  md_check_recovery+0x51/0x540 [md_mod]
[  902.621762]  raid1d+0x5c/0xeb0 [raid1]
[  902.621939]  ? try_to_del_timer_sync+0x4d/0x80
[  902.622102]  ? del_timer_sync+0x35/0x40
[  902.622265]  ? schedule_timeout+0x177/0x360
[  902.622453]  ? call_timer_fn+0x130/0x130
[  902.622623]  ? find_pers+0x70/0x70 [md_mod]
[  902.622794]  ? md_thread+0x94/0x150 [md_mod]
[  902.622959]  md_thread+0x94/0x150 [md_mod]
[  902.623121]  ? wait_woken+0x80/0x80
[  902.623280]  kthread+0x119/0x130
[  902.623437]  ? kthread_create_on_node+0x60/0x60
[  902.623600]  ret_from_fork+0x22/0x40
[  902.624225] RIP: bitmap_file_clear_bit+0x90/0xd0 [md_mod] RSP: ffffb52e4c707d28

Because mdadm was running on another cpu to do resize, so bitmap_resize was
called to replace bitmap as below shows.

PID: 38801  TASK: ffff9ad074a90e00  CPU: 0   COMMAND: "mdadm"
   [exception RIP: queued_spin_lock_slowpath+56]
   [snip]
-- <NMI exception stack> --
 #5 [ffffb52e60f17c58] queued_spin_lock_slowpath at ffffffff9c0b27b8
 #6 [ffffb52e60f17c58] bitmap_resize at ffffffffc0399877 [md_mod]
 #7 [ffffb52e60f17d30] raid1_resize at ffffffffc0285bf9 [raid1]
 #8 [ffffb52e60f17d50] update_size at ffffffffc038a31a [md_mod]
 #9 [ffffb52e60f17d70] md_ioctl at ffffffffc0395ca4 [md_mod]

And the procedure to keep resize bitmap safe is allocate new storage
space, then quiesce, copy bits, replace bitmap, and re-start.

However the daemon (bitmap_daemon_work) could happen even the array is
quiesced, which means when bitmap_file_clear_bit is triggered by raid1d,
then it thinks it should be fine to access store->filemap since
counts->lock is held, but resize could change the storage without the
protection of the lock.

Cc: Jack Wang <[email protected]>
Cc: NeilBrown <[email protected]>
Signed-off-by: Guoqing Jiang <[email protected]>
Signed-off-by: Song Liu <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jan 6, 2020
[ Upstream commit 32546a9 ]

This patch moves the final part of the cifsFileInfo_put() logic where we
need a write lock on lock_sem to be processed in a separate thread that
holds no other locks.
This is to prevent deadlocks like the one below:

> there are 6 processes looping to while trying to down_write
> cinode->lock_sem, 5 of them from _cifsFileInfo_put, and one from
> cifs_new_fileinfo
>
> and there are 5 other processes which are blocked, several of them
> waiting on either PG_writeback or PG_locked (which are both set), all
> for the same page of the file
>
> 2 inode_lock() (inode->i_rwsem) for the file
> 1 wait_on_page_writeback() for the page
> 1 down_read(inode->i_rwsem) for the inode of the directory
> 1 inode_lock()(inode->i_rwsem) for the inode of the directory
> 1 __lock_page
>
>
> so processes are blocked waiting on:
>   page flags PG_locked and PG_writeback for one specific page
>   inode->i_rwsem for the directory
>   inode->i_rwsem for the file
>   cifsInodeInflock_sem
>
>
>
> here are the more gory details (let me know if I need to provide
> anything more/better):
>
> [0 00:48:22.765] [UN]  PID: 8863   TASK: ffff8c691547c5c0  CPU: 3
> COMMAND: "reopen_file"
>  #0 [ffff9965007e3ba8] __schedule at ffffffff9b6e6095
>  #1 [ffff9965007e3c38] schedule at ffffffff9b6e64df
>  #2 [ffff9965007e3c48] rwsem_down_write_slowpath at ffffffff9af283d7
>  #3 [ffff9965007e3cb8] legitimize_path at ffffffff9b0f975d
>  #4 [ffff9965007e3d08] path_openat at ffffffff9b0fe55d
>  #5 [ffff9965007e3dd8] do_filp_open at ffffffff9b100a33
>  #6 [ffff9965007e3ee0] do_sys_open at ffffffff9b0eb2d6
>  #7 [ffff9965007e3f38] do_syscall_64 at ffffffff9ae04315
> * (I think legitimize_path is bogus)
>
> in path_openat
>         } else {
>                 const char *s = path_init(nd, flags);
>                 while (!(error = link_path_walk(s, nd)) &&
>                         (error = do_last(nd, file, op)) > 0) {  <<<<
>
> do_last:
>         if (open_flag & O_CREAT)
>                 inode_lock(dir->d_inode);  <<<<
>         else
> so it's trying to take inode->i_rwsem for the directory
>
>      DENTRY           INODE           SUPERBLK     TYPE PATH
> ffff8c68bb8e79c0 ffff8c691158ef20 ffff8c6915bf9000 DIR  /mnt/vm1_smb/
> inode.i_rwsem is ffff8c691158efc0
>
> <struct rw_semaphore 0xffff8c691158efc0>:
>         owner: <struct task_struct 0xffff8c6914275d00> (UN -   8856 -
> reopen_file), counter: 0x0000000000000003
>         waitlist: 2
>         0xffff9965007e3c90     8863   reopen_file      UN 0  1:29:22.926
>   RWSEM_WAITING_FOR_WRITE
>         0xffff996500393e00     9802   ls               UN 0  1:17:26.700
>   RWSEM_WAITING_FOR_READ
>
>
> the owner of the inode.i_rwsem of the directory is:
>
> [0 00:00:00.109] [UN]  PID: 8856   TASK: ffff8c6914275d00  CPU: 3
> COMMAND: "reopen_file"
>  #0 [ffff99650065b828] __schedule at ffffffff9b6e6095
>  #1 [ffff99650065b8b8] schedule at ffffffff9b6e64df
>  #2 [ffff99650065b8c8] schedule_timeout at ffffffff9b6e9f89
>  #3 [ffff99650065b940] msleep at ffffffff9af573a9
>  #4 [ffff99650065b948] _cifsFileInfo_put.cold.63 at ffffffffc0a42dd6 [cifs]
>  #5 [ffff99650065ba38] cifs_writepage_locked at ffffffffc0a0b8f3 [cifs]
>  #6 [ffff99650065bab0] cifs_launder_page at ffffffffc0a0bb72 [cifs]
>  #7 [ffff99650065bb30] invalidate_inode_pages2_range at ffffffff9b04d4bd
>  #8 [ffff99650065bcb8] cifs_invalidate_mapping at ffffffffc0a11339 [cifs]
>  #9 [ffff99650065bcd0] cifs_revalidate_mapping at ffffffffc0a1139a [cifs]
> #10 [ffff99650065bcf0] cifs_d_revalidate at ffffffffc0a014f6 [cifs]
> #11 [ffff99650065bd08] path_openat at ffffffff9b0fe7f7
> #12 [ffff99650065bdd8] do_filp_open at ffffffff9b100a33
> #13 [ffff99650065bee0] do_sys_open at ffffffff9b0eb2d6
> #14 [ffff99650065bf38] do_syscall_64 at ffffffff9ae04315
>
> cifs_launder_page is for page 0xffffd1e2c07d2480
>
> crash> page.index,mapping,flags 0xffffd1e2c07d2480
>       index = 0x8
>       mapping = 0xffff8c68f3cd0db0
>   flags = 0xfffffc0008095
>
>   PAGE-FLAG       BIT  VALUE
>   PG_locked         0  0000001
>   PG_uptodate       2  0000004
>   PG_lru            4  0000010
>   PG_waiters        7  0000080
>   PG_writeback     15  0008000
>
>
> inode is ffff8c68f3cd0c40
> inode.i_rwsem is ffff8c68f3cd0ce0
>      DENTRY           INODE           SUPERBLK     TYPE PATH
> ffff8c68a1f1b480 ffff8c68f3cd0c40 ffff8c6915bf9000 REG
> /mnt/vm1_smb/testfile.8853
>
>
> this process holds the inode->i_rwsem for the parent directory, is
> laundering a page attached to the inode of the file it's opening, and in
> _cifsFileInfo_put is trying to down_write the cifsInodeInflock_sem
> for the file itself.
>
>
> <struct rw_semaphore 0xffff8c68f3cd0ce0>:
>         owner: <struct task_struct 0xffff8c6914272e80> (UN -   8854 -
> reopen_file), counter: 0x0000000000000003
>         waitlist: 1
>         0xffff9965005dfd80     8855   reopen_file      UN 0  1:29:22.912
>   RWSEM_WAITING_FOR_WRITE
>
> this is the inode.i_rwsem for the file
>
> the owner:
>
> [0 00:48:22.739] [UN]  PID: 8854   TASK: ffff8c6914272e80  CPU: 2
> COMMAND: "reopen_file"
>  #0 [ffff99650054fb38] __schedule at ffffffff9b6e6095
>  #1 [ffff99650054fbc8] schedule at ffffffff9b6e64df
>  #2 [ffff99650054fbd8] io_schedule at ffffffff9b6e68e2
>  #3 [ffff99650054fbe8] __lock_page at ffffffff9b03c56f
>  #4 [ffff99650054fc80] pagecache_get_page at ffffffff9b03dcdf
>  #5 [ffff99650054fcc0] grab_cache_page_write_begin at ffffffff9b03ef4c
>  #6 [ffff99650054fcd0] cifs_write_begin at ffffffffc0a064ec [cifs]
>  #7 [ffff99650054fd30] generic_perform_write at ffffffff9b03bba4
>  #8 [ffff99650054fda8] __generic_file_write_iter at ffffffff9b04060a
>  #9 [ffff99650054fdf0] cifs_strict_writev.cold.70 at ffffffffc0a4469b [cifs]
> #10 [ffff99650054fe48] new_sync_write at ffffffff9b0ec1dd
> #11 [ffff99650054fed0] vfs_write at ffffffff9b0eed35
> #12 [ffff99650054ff00] ksys_write at ffffffff9b0eefd9
> #13 [ffff99650054ff38] do_syscall_64 at ffffffff9ae04315
>
> the process holds the inode->i_rwsem for the file to which it's writing,
> and is trying to __lock_page for the same page as in the other processes
>
>
> the other tasks:
> [0 00:00:00.028] [UN]  PID: 8859   TASK: ffff8c6915479740  CPU: 2
> COMMAND: "reopen_file"
>  #0 [ffff9965007b39d8] __schedule at ffffffff9b6e6095
>  #1 [ffff9965007b3a68] schedule at ffffffff9b6e64df
>  #2 [ffff9965007b3a78] schedule_timeout at ffffffff9b6e9f89
>  #3 [ffff9965007b3af0] msleep at ffffffff9af573a9
>  #4 [ffff9965007b3af8] cifs_new_fileinfo.cold.61 at ffffffffc0a42a07 [cifs]
>  #5 [ffff9965007b3b78] cifs_open at ffffffffc0a0709d [cifs]
>  #6 [ffff9965007b3cd8] do_dentry_open at ffffffff9b0e9b7a
>  #7 [ffff9965007b3d08] path_openat at ffffffff9b0fe34f
>  #8 [ffff9965007b3dd8] do_filp_open at ffffffff9b100a33
>  #9 [ffff9965007b3ee0] do_sys_open at ffffffff9b0eb2d6
> #10 [ffff9965007b3f38] do_syscall_64 at ffffffff9ae04315
>
> this is opening the file, and is trying to down_write cinode->lock_sem
>
>
> [0 00:00:00.041] [UN]  PID: 8860   TASK: ffff8c691547ae80  CPU: 2
> COMMAND: "reopen_file"
> [0 00:00:00.057] [UN]  PID: 8861   TASK: ffff8c6915478000  CPU: 3
> COMMAND: "reopen_file"
> [0 00:00:00.059] [UN]  PID: 8858   TASK: ffff8c6914271740  CPU: 2
> COMMAND: "reopen_file"
> [0 00:00:00.109] [UN]  PID: 8862   TASK: ffff8c691547dd00  CPU: 6
> COMMAND: "reopen_file"
>  #0 [ffff9965007c3c78] __schedule at ffffffff9b6e6095
>  #1 [ffff9965007c3d08] schedule at ffffffff9b6e64df
>  #2 [ffff9965007c3d18] schedule_timeout at ffffffff9b6e9f89
>  #3 [ffff9965007c3d90] msleep at ffffffff9af573a9
>  #4 [ffff9965007c3d98] _cifsFileInfo_put.cold.63 at ffffffffc0a42dd6 [cifs]
>  #5 [ffff9965007c3e88] cifs_close at ffffffffc0a07aaf [cifs]
>  #6 [ffff9965007c3ea0] __fput at ffffffff9b0efa6e
>  #7 [ffff9965007c3ee8] task_work_run at ffffffff9aef1614
>  #8 [ffff9965007c3f20] exit_to_usermode_loop at ffffffff9ae03d6f
>  #9 [ffff9965007c3f38] do_syscall_64 at ffffffff9ae0444c
>
> closing the file, and trying to down_write cifsi->lock_sem
>
>
> [0 00:48:22.839] [UN]  PID: 8857   TASK: ffff8c6914270000  CPU: 7
> COMMAND: "reopen_file"
>  #0 [ffff9965006a7cc8] __schedule at ffffffff9b6e6095
>  #1 [ffff9965006a7d58] schedule at ffffffff9b6e64df
>  #2 [ffff9965006a7d68] io_schedule at ffffffff9b6e68e2
>  #3 [ffff9965006a7d78] wait_on_page_bit at ffffffff9b03cac6
>  #4 [ffff9965006a7e10] __filemap_fdatawait_range at ffffffff9b03b028
>  #5 [ffff9965006a7ed8] filemap_write_and_wait at ffffffff9b040165
>  #6 [ffff9965006a7ef0] cifs_flush at ffffffffc0a0c2fa [cifs]
>  #7 [ffff9965006a7f10] filp_close at ffffffff9b0e93f1
>  #8 [ffff9965006a7f30] __x64_sys_close at ffffffff9b0e9a0e
>  #9 [ffff9965006a7f38] do_syscall_64 at ffffffff9ae04315
>
> in __filemap_fdatawait_range
>                         wait_on_page_writeback(page);
> for the same page of the file
>
>
>
> [0 00:48:22.718] [UN]  PID: 8855   TASK: ffff8c69142745c0  CPU: 7
> COMMAND: "reopen_file"
>  #0 [ffff9965005dfc98] __schedule at ffffffff9b6e6095
>  #1 [ffff9965005dfd28] schedule at ffffffff9b6e64df
>  #2 [ffff9965005dfd38] rwsem_down_write_slowpath at ffffffff9af283d7
>  #3 [ffff9965005dfdf0] cifs_strict_writev at ffffffffc0a0c40a [cifs]
>  #4 [ffff9965005dfe48] new_sync_write at ffffffff9b0ec1dd
>  #5 [ffff9965005dfed0] vfs_write at ffffffff9b0eed35
>  #6 [ffff9965005dff00] ksys_write at ffffffff9b0eefd9
>  #7 [ffff9965005dff38] do_syscall_64 at ffffffff9ae04315
>
>         inode_lock(inode);
>
>
> and one 'ls' later on, to see whether the rest of the mount is available
> (the test file is in the root, so we get blocked up on the directory
> ->i_rwsem), so the entire mount is unavailable
>
> [0 00:36:26.473] [UN]  PID: 9802   TASK: ffff8c691436ae80  CPU: 4
> COMMAND: "ls"
>  #0 [ffff996500393d28] __schedule at ffffffff9b6e6095
>  #1 [ffff996500393db8] schedule at ffffffff9b6e64df
>  #2 [ffff996500393dc8] rwsem_down_read_slowpath at ffffffff9b6e9421
>  #3 [ffff996500393e78] down_read_killable at ffffffff9b6e95e2
>  #4 [ffff996500393e88] iterate_dir at ffffffff9b103c56
>  #5 [ffff996500393ec8] ksys_getdents64 at ffffffff9b104b0c
>  #6 [ffff996500393f30] __x64_sys_getdents64 at ffffffff9b104bb6
>  #7 [ffff996500393f38] do_syscall_64 at ffffffff9ae04315
>
> in iterate_dir:
>         if (shared)
>                 res = down_read_killable(&inode->i_rwsem);  <<<<
>         else
>                 res = down_write_killable(&inode->i_rwsem);
>

Reported-by: Frank Sorenson <[email protected]>
Reviewed-by: Pavel Shilovsky <[email protected]>
Signed-off-by: Ronnie Sahlberg <[email protected]>
Signed-off-by: Steve French <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Feb 4, 2020
[ Upstream commit 5eed6f1 ]

Commit 9b6f7e1 ("mm: rework memcg kernel stack accounting") will
result in fork failing if allocating a kernel stack for a task in
dup_task_struct exceeds the kernel memory allowance for that cgroup.

Unfortunately, it also results in a crash.

This is due to the code jumping to free_stack and calling
free_thread_stack when the memcg kernel stack charge fails, but without
tsk->stack pointing at the freshly allocated stack.

This in turn results in the vfree_atomic in free_thread_stack oopsing
with a backtrace like this:

#5 [ffffc900244efc88] die at ffffffff8101f0ab
 #6 [ffffc900244efcb8] do_general_protection at ffffffff8101cb86
 #7 [ffffc900244efce0] general_protection at ffffffff818ff082
    [exception RIP: llist_add_batch+7]
    RIP: ffffffff8150d487  RSP: ffffc900244efd98  RFLAGS: 00010282
    RAX: 0000000000000000  RBX: ffff88085ef55980  RCX: 0000000000000000
    RDX: ffff88085ef55980  RSI: 343834343531203a  RDI: 343834343531203a
    RBP: ffffc900244efd98   R8: 0000000000000001   R9: ffff8808578c3600
    R10: 0000000000000000  R11: 0000000000000001  R12: ffff88029f6c21c0
    R13: 0000000000000286  R14: ffff880147759b00  R15: 0000000000000000
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #8 [ffffc900244efda0] vfree_atomic at ffffffff811df2c7
 #9 [ffffc900244efdb8] copy_process at ffffffff81086e37
#10 [ffffc900244efe98] _do_fork at ffffffff810884e0
#11 [ffffc900244eff10] sys_vfork at ffffffff810887ff
#12 [ffffc900244eff20] do_syscall_64 at ffffffff81002a43
    RIP: 000000000049b948  RSP: 00007ffcdb307830  RFLAGS: 00000246
    RAX: ffffffffffffffda  RBX: 0000000000896030  RCX: 000000000049b948
    RDX: 0000000000000000  RSI: 00007ffcdb307790  RDI: 00000000005d7421
    RBP: 000000000067370f   R8: 00007ffcdb3077b0   R9: 000000000001ed00
    R10: 0000000000000008  R11: 0000000000000246  R12: 0000000000000040
    R13: 000000000000000f  R14: 0000000000000000  R15: 000000000088d018
    ORIG_RAX: 000000000000003a  CS: 0033  SS: 002b

The simplest fix is to assign tsk->stack right where it is allocated.

Link: http://lkml.kernel.org/r/[email protected]
Fixes: 9b6f7e1 ("mm: rework memcg kernel stack accounting")
Signed-off-by: Rik van Riel <[email protected]>
Acked-by: Roman Gushchin <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Shakeel Butt <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Feb 4, 2020
Hayes Wang says:

====================
r8152: serial fixes

v3:
1. Fix the typos for patch #5 and #6.
2. Modify the commit message of patch #9.

v2:
For patch #2, move declaring the variable "ocp_data".

v1:
These patches are used to fix some issues for RTL8153.
====================

Signed-off-by: David S. Miller <[email protected]>
anthraxx pushed a commit that referenced this pull request Feb 13, 2020
[ Upstream commit 96bf313ecb33567af4cb53928b0c951254a02759 ]

There exists a deadlock with range_cyclic that has existed forever.  If
we loop around with a bio already built we could deadlock with a writer
who has the page locked that we're attempting to write but is waiting on
a page in our bio to be written out.  The task traces are as follows

  PID: 1329874  TASK: ffff889ebcdf3800  CPU: 33  COMMAND: "kworker/u113:5"
   #0 [ffffc900297bb658] __schedule at ffffffff81a4c33f
   #1 [ffffc900297bb6e0] schedule at ffffffff81a4c6e3
   #2 [ffffc900297bb6f8] io_schedule at ffffffff81a4ca42
   #3 [ffffc900297bb708] __lock_page at ffffffff811f145b
   #4 [ffffc900297bb798] __process_pages_contig at ffffffff814bc502
   #5 [ffffc900297bb8c8] lock_delalloc_pages at ffffffff814bc684
   #6 [ffffc900297bb900] find_lock_delalloc_range at ffffffff814be9ff
   #7 [ffffc900297bb9a0] writepage_delalloc at ffffffff814bebd0
   #8 [ffffc900297bba18] __extent_writepage at ffffffff814bfbf2
   #9 [ffffc900297bba98] extent_write_cache_pages at ffffffff814bffbd

  PID: 2167901  TASK: ffff889dc6a59c00  CPU: 14  COMMAND:
  "aio-dio-invalid"
   #0 [ffffc9003b50bb18] __schedule at ffffffff81a4c33f
   #1 [ffffc9003b50bba0] schedule at ffffffff81a4c6e3
   #2 [ffffc9003b50bbb8] io_schedule at ffffffff81a4ca42
   #3 [ffffc9003b50bbc8] wait_on_page_bit at ffffffff811f24d6
   #4 [ffffc9003b50bc60] prepare_pages at ffffffff814b05a7
   #5 [ffffc9003b50bcd8] btrfs_buffered_write at ffffffff814b1359
   #6 [ffffc9003b50bdb0] btrfs_file_write_iter at ffffffff814b5933
   #7 [ffffc9003b50be38] new_sync_write at ffffffff8128f6a8
   #8 [ffffc9003b50bec8] vfs_write at ffffffff81292b9d
   #9 [ffffc9003b50bf00] ksys_pwrite64 at ffffffff81293032

I used drgn to find the respective pages we were stuck on

page_entry.page 0xffffea00fbfc7500 index 8148 bit 15 pid 2167901
page_entry.page 0xffffea00f9bb7400 index 7680 bit 0 pid 1329874

As you can see the kworker is waiting for bit 0 (PG_locked) on index
7680, and aio-dio-invalid is waiting for bit 15 (PG_writeback) on index
8148.  aio-dio-invalid has 7680, and the kworker epd looks like the
following

  crash> struct extent_page_data ffffc900297bbbb0
  struct extent_page_data {
    bio = 0xffff889f747ed830,
    tree = 0xffff889eed6ba448,
    extent_locked = 0,
    sync_io = 0
  }

Probably worth mentioning as well that it waits for writeback of the
page to complete while holding a lock on it (at prepare_pages()).

Using drgn I walked the bio pages looking for page
0xffffea00fbfc7500 which is the one we're waiting for writeback on

  bio = Object(prog, 'struct bio', address=0xffff889f747ed830)
  for i in range(0, bio.bi_vcnt.value_()):
      bv = bio.bi_io_vec[i]
      if bv.bv_page.value_() == 0xffffea00fbfc7500:
	  print("FOUND IT")

which validated what I suspected.

The fix for this is simple, flush the epd before we loop back around to
the beginning of the file during writeout.

Fixes: b293f02 ("Btrfs: Add writepages support")
CC: [email protected] # 4.4+
Reviewed-by: Filipe Manana <[email protected]>
Signed-off-by: Josef Bacik <[email protected]>
Signed-off-by: David Sterba <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Feb 13, 2020
commit 42ffb0b upstream.

There exists a deadlock with range_cyclic that has existed forever.  If
we loop around with a bio already built we could deadlock with a writer
who has the page locked that we're attempting to write but is waiting on
a page in our bio to be written out.  The task traces are as follows

  PID: 1329874  TASK: ffff889ebcdf3800  CPU: 33  COMMAND: "kworker/u113:5"
   #0 [ffffc900297bb658] __schedule at ffffffff81a4c33f
   #1 [ffffc900297bb6e0] schedule at ffffffff81a4c6e3
   #2 [ffffc900297bb6f8] io_schedule at ffffffff81a4ca42
   #3 [ffffc900297bb708] __lock_page at ffffffff811f145b
   #4 [ffffc900297bb798] __process_pages_contig at ffffffff814bc502
   #5 [ffffc900297bb8c8] lock_delalloc_pages at ffffffff814bc684
   #6 [ffffc900297bb900] find_lock_delalloc_range at ffffffff814be9ff
   #7 [ffffc900297bb9a0] writepage_delalloc at ffffffff814bebd0
   #8 [ffffc900297bba18] __extent_writepage at ffffffff814bfbf2
   #9 [ffffc900297bba98] extent_write_cache_pages at ffffffff814bffbd

  PID: 2167901  TASK: ffff889dc6a59c00  CPU: 14  COMMAND:
  "aio-dio-invalid"
   #0 [ffffc9003b50bb18] __schedule at ffffffff81a4c33f
   #1 [ffffc9003b50bba0] schedule at ffffffff81a4c6e3
   #2 [ffffc9003b50bbb8] io_schedule at ffffffff81a4ca42
   #3 [ffffc9003b50bbc8] wait_on_page_bit at ffffffff811f24d6
   #4 [ffffc9003b50bc60] prepare_pages at ffffffff814b05a7
   #5 [ffffc9003b50bcd8] btrfs_buffered_write at ffffffff814b1359
   #6 [ffffc9003b50bdb0] btrfs_file_write_iter at ffffffff814b5933
   #7 [ffffc9003b50be38] new_sync_write at ffffffff8128f6a8
   #8 [ffffc9003b50bec8] vfs_write at ffffffff81292b9d
   #9 [ffffc9003b50bf00] ksys_pwrite64 at ffffffff81293032

I used drgn to find the respective pages we were stuck on

page_entry.page 0xffffea00fbfc7500 index 8148 bit 15 pid 2167901
page_entry.page 0xffffea00f9bb7400 index 7680 bit 0 pid 1329874

As you can see the kworker is waiting for bit 0 (PG_locked) on index
7680, and aio-dio-invalid is waiting for bit 15 (PG_writeback) on index
8148.  aio-dio-invalid has 7680, and the kworker epd looks like the
following

  crash> struct extent_page_data ffffc900297bbbb0
  struct extent_page_data {
    bio = 0xffff889f747ed830,
    tree = 0xffff889eed6ba448,
    extent_locked = 0,
    sync_io = 0
  }

Probably worth mentioning as well that it waits for writeback of the
page to complete while holding a lock on it (at prepare_pages()).

Using drgn I walked the bio pages looking for page
0xffffea00fbfc7500 which is the one we're waiting for writeback on

  bio = Object(prog, 'struct bio', address=0xffff889f747ed830)
  for i in range(0, bio.bi_vcnt.value_()):
      bv = bio.bi_io_vec[i]
      if bv.bv_page.value_() == 0xffffea00fbfc7500:
	  print("FOUND IT")

which validated what I suspected.

The fix for this is simple, flush the epd before we loop back around to
the beginning of the file during writeout.

Fixes: b293f02 ("Btrfs: Add writepages support")
CC: [email protected] # 4.4+
Reviewed-by: Filipe Manana <[email protected]>
Signed-off-by: Josef Bacik <[email protected]>
Signed-off-by: David Sterba <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx pushed a commit that referenced this pull request Feb 16, 2020
[ Upstream commit 42ffb0b ]

There exists a deadlock with range_cyclic that has existed forever.  If
we loop around with a bio already built we could deadlock with a writer
who has the page locked that we're attempting to write but is waiting on
a page in our bio to be written out.  The task traces are as follows

  PID: 1329874  TASK: ffff889ebcdf3800  CPU: 33  COMMAND: "kworker/u113:5"
   #0 [ffffc900297bb658] __schedule at ffffffff81a4c33f
   #1 [ffffc900297bb6e0] schedule at ffffffff81a4c6e3
   #2 [ffffc900297bb6f8] io_schedule at ffffffff81a4ca42
   #3 [ffffc900297bb708] __lock_page at ffffffff811f145b
   #4 [ffffc900297bb798] __process_pages_contig at ffffffff814bc502
   #5 [ffffc900297bb8c8] lock_delalloc_pages at ffffffff814bc684
   #6 [ffffc900297bb900] find_lock_delalloc_range at ffffffff814be9ff
   #7 [ffffc900297bb9a0] writepage_delalloc at ffffffff814bebd0
   #8 [ffffc900297bba18] __extent_writepage at ffffffff814bfbf2
   #9 [ffffc900297bba98] extent_write_cache_pages at ffffffff814bffbd

  PID: 2167901  TASK: ffff889dc6a59c00  CPU: 14  COMMAND:
  "aio-dio-invalid"
   #0 [ffffc9003b50bb18] __schedule at ffffffff81a4c33f
   #1 [ffffc9003b50bba0] schedule at ffffffff81a4c6e3
   #2 [ffffc9003b50bbb8] io_schedule at ffffffff81a4ca42
   #3 [ffffc9003b50bbc8] wait_on_page_bit at ffffffff811f24d6
   #4 [ffffc9003b50bc60] prepare_pages at ffffffff814b05a7
   #5 [ffffc9003b50bcd8] btrfs_buffered_write at ffffffff814b1359
   #6 [ffffc9003b50bdb0] btrfs_file_write_iter at ffffffff814b5933
   #7 [ffffc9003b50be38] new_sync_write at ffffffff8128f6a8
   #8 [ffffc9003b50bec8] vfs_write at ffffffff81292b9d
   #9 [ffffc9003b50bf00] ksys_pwrite64 at ffffffff81293032

I used drgn to find the respective pages we were stuck on

page_entry.page 0xffffea00fbfc7500 index 8148 bit 15 pid 2167901
page_entry.page 0xffffea00f9bb7400 index 7680 bit 0 pid 1329874

As you can see the kworker is waiting for bit 0 (PG_locked) on index
7680, and aio-dio-invalid is waiting for bit 15 (PG_writeback) on index
8148.  aio-dio-invalid has 7680, and the kworker epd looks like the
following

  crash> struct extent_page_data ffffc900297bbbb0
  struct extent_page_data {
    bio = 0xffff889f747ed830,
    tree = 0xffff889eed6ba448,
    extent_locked = 0,
    sync_io = 0
  }

Probably worth mentioning as well that it waits for writeback of the
page to complete while holding a lock on it (at prepare_pages()).

Using drgn I walked the bio pages looking for page
0xffffea00fbfc7500 which is the one we're waiting for writeback on

  bio = Object(prog, 'struct bio', address=0xffff889f747ed830)
  for i in range(0, bio.bi_vcnt.value_()):
      bv = bio.bi_io_vec[i]
      if bv.bv_page.value_() == 0xffffea00fbfc7500:
	  print("FOUND IT")

which validated what I suspected.

The fix for this is simple, flush the epd before we loop back around to
the beginning of the file during writeout.

Fixes: b293f02 ("Btrfs: Add writepages support")
CC: [email protected] # 4.4+
Reviewed-by: Filipe Manana <[email protected]>
Signed-off-by: Josef Bacik <[email protected]>
Signed-off-by: David Sterba <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Mar 17, 2020
commit 42ffb0b upstream.

There exists a deadlock with range_cyclic that has existed forever.  If
we loop around with a bio already built we could deadlock with a writer
who has the page locked that we're attempting to write but is waiting on
a page in our bio to be written out.  The task traces are as follows

  PID: 1329874  TASK: ffff889ebcdf3800  CPU: 33  COMMAND: "kworker/u113:5"
   #0 [ffffc900297bb658] __schedule at ffffffff81a4c33f
   #1 [ffffc900297bb6e0] schedule at ffffffff81a4c6e3
   #2 [ffffc900297bb6f8] io_schedule at ffffffff81a4ca42
   #3 [ffffc900297bb708] __lock_page at ffffffff811f145b
   #4 [ffffc900297bb798] __process_pages_contig at ffffffff814bc502
   #5 [ffffc900297bb8c8] lock_delalloc_pages at ffffffff814bc684
   #6 [ffffc900297bb900] find_lock_delalloc_range at ffffffff814be9ff
   #7 [ffffc900297bb9a0] writepage_delalloc at ffffffff814bebd0
   #8 [ffffc900297bba18] __extent_writepage at ffffffff814bfbf2
   #9 [ffffc900297bba98] extent_write_cache_pages at ffffffff814bffbd

  PID: 2167901  TASK: ffff889dc6a59c00  CPU: 14  COMMAND:
  "aio-dio-invalid"
   #0 [ffffc9003b50bb18] __schedule at ffffffff81a4c33f
   #1 [ffffc9003b50bba0] schedule at ffffffff81a4c6e3
   #2 [ffffc9003b50bbb8] io_schedule at ffffffff81a4ca42
   #3 [ffffc9003b50bbc8] wait_on_page_bit at ffffffff811f24d6
   #4 [ffffc9003b50bc60] prepare_pages at ffffffff814b05a7
   #5 [ffffc9003b50bcd8] btrfs_buffered_write at ffffffff814b1359
   #6 [ffffc9003b50bdb0] btrfs_file_write_iter at ffffffff814b5933
   #7 [ffffc9003b50be38] new_sync_write at ffffffff8128f6a8
   #8 [ffffc9003b50bec8] vfs_write at ffffffff81292b9d
   #9 [ffffc9003b50bf00] ksys_pwrite64 at ffffffff81293032

I used drgn to find the respective pages we were stuck on

page_entry.page 0xffffea00fbfc7500 index 8148 bit 15 pid 2167901
page_entry.page 0xffffea00f9bb7400 index 7680 bit 0 pid 1329874

As you can see the kworker is waiting for bit 0 (PG_locked) on index
7680, and aio-dio-invalid is waiting for bit 15 (PG_writeback) on index
8148.  aio-dio-invalid has 7680, and the kworker epd looks like the
following

  crash> struct extent_page_data ffffc900297bbbb0
  struct extent_page_data {
    bio = 0xffff889f747ed830,
    tree = 0xffff889eed6ba448,
    extent_locked = 0,
    sync_io = 0
  }

Probably worth mentioning as well that it waits for writeback of the
page to complete while holding a lock on it (at prepare_pages()).

Using drgn I walked the bio pages looking for page
0xffffea00fbfc7500 which is the one we're waiting for writeback on

  bio = Object(prog, 'struct bio', address=0xffff889f747ed830)
  for i in range(0, bio.bi_vcnt.value_()):
      bv = bio.bi_io_vec[i]
      if bv.bv_page.value_() == 0xffffea00fbfc7500:
	  print("FOUND IT")

which validated what I suspected.

The fix for this is simple, flush the epd before we loop back around to
the beginning of the file during writeout.

Fixes: b293f02 ("Btrfs: Add writepages support")
CC: [email protected] # 4.4+
Reviewed-by: Filipe Manana <[email protected]>
Signed-off-by: Josef Bacik <[email protected]>
Signed-off-by: David Sterba <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx pushed a commit that referenced this pull request Mar 30, 2020
When experimenting with bpf_send_signal() helper in our production
environment (5.2 based), we experienced a deadlock in NMI mode:
   #5 [ffffc9002219f770] queued_spin_lock_slowpath at ffffffff8110be24
   #6 [ffffc9002219f770] _raw_spin_lock_irqsave at ffffffff81a43012
   #7 [ffffc9002219f780] try_to_wake_up at ffffffff810e7ecd
   #8 [ffffc9002219f7e0] signal_wake_up_state at ffffffff810c7b55
   #9 [ffffc9002219f7f0] __send_signal at ffffffff810c8602
  #10 [ffffc9002219f830] do_send_sig_info at ffffffff810ca31a
  #11 [ffffc9002219f868] bpf_send_signal at ffffffff8119d227
  #12 [ffffc9002219f988] bpf_overflow_handler at ffffffff811d4140
  #13 [ffffc9002219f9e0] __perf_event_overflow at ffffffff811d68cf
  #14 [ffffc9002219fa10] perf_swevent_overflow at ffffffff811d6a09
  #15 [ffffc9002219fa38] ___perf_sw_event at ffffffff811e0f47
  #16 [ffffc9002219fc30] __schedule at ffffffff81a3e04d
  #17 [ffffc9002219fc90] schedule at ffffffff81a3e219
  #18 [ffffc9002219fca0] futex_wait_queue_me at ffffffff8113d1b9
  #19 [ffffc9002219fcd8] futex_wait at ffffffff8113e529
  #20 [ffffc9002219fdf0] do_futex at ffffffff8113ffbc
  #21 [ffffc9002219fec0] __x64_sys_futex at ffffffff81140d1c
  #22 [ffffc9002219ff38] do_syscall_64 at ffffffff81002602
  #23 [ffffc9002219ff50] entry_SYSCALL_64_after_hwframe at ffffffff81c00068

The above call stack is actually very similar to an issue
reported by Commit eac9153 ("bpf/stackmap: Fix deadlock with
rq_lock in bpf_get_stack()") by Song Liu. The only difference is
bpf_send_signal() helper instead of bpf_get_stack() helper.

The above deadlock is triggered with a perf_sw_event.
Similar to Commit eac9153, the below almost identical reproducer
used tracepoint point sched/sched_switch so the issue can be easily caught.
  /* stress_test.c */
  #include <stdio.h>
  #include <stdlib.h>
  #include <sys/mman.h>
  #include <pthread.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <fcntl.h>

  #define THREAD_COUNT 1000
  char *filename;
  void *worker(void *p)
  {
        void *ptr;
        int fd;
        char *pptr;

        fd = open(filename, O_RDONLY);
        if (fd < 0)
                return NULL;
        while (1) {
                struct timespec ts = {0, 1000 + rand() % 2000};

                ptr = mmap(NULL, 4096 * 64, PROT_READ, MAP_PRIVATE, fd, 0);
                usleep(1);
                if (ptr == MAP_FAILED) {
                        printf("failed to mmap\n");
                        break;
                }
                munmap(ptr, 4096 * 64);
                usleep(1);
                pptr = malloc(1);
                usleep(1);
                pptr[0] = 1;
                usleep(1);
                free(pptr);
                usleep(1);
                nanosleep(&ts, NULL);
        }
        close(fd);
        return NULL;
  }

  int main(int argc, char *argv[])
  {
        void *ptr;
        int i;
        pthread_t threads[THREAD_COUNT];

        if (argc < 2)
                return 0;

        filename = argv[1];

        for (i = 0; i < THREAD_COUNT; i++) {
                if (pthread_create(threads + i, NULL, worker, NULL)) {
                        fprintf(stderr, "Error creating thread\n");
                        return 0;
                }
        }

        for (i = 0; i < THREAD_COUNT; i++)
                pthread_join(threads[i], NULL);
        return 0;
  }
and the following command:
  1. run `stress_test /bin/ls` in one windown
  2. hack bcc trace.py with the following change:
     --- a/tools/trace.py
     +++ b/tools/trace.py
     @@ -513,6 +513,7 @@ BPF_PERF_OUTPUT(%s);
              __data.tgid = __tgid;
              __data.pid = __pid;
              bpf_get_current_comm(&__data.comm, sizeof(__data.comm));
     +        bpf_send_signal(10);
      %s
      %s
              %s.perf_submit(%s, &__data, sizeof(__data));
  3. in a different window run
     ./trace.py -p $(pidof stress_test) t:sched:sched_switch

The deadlock can be reproduced in our production system.

Similar to Song's fix, the fix is to delay sending signal if
irqs is disabled to avoid deadlocks involving with rq_lock.
With this change, my above stress-test in our production system
won't cause deadlock any more.

I also implemented a scale-down version of reproducer in the
selftest (a subsequent commit). With latest bpf-next,
it complains for the following potential deadlock.
  [   32.832450] -> #1 (&p->pi_lock){-.-.}:
  [   32.833100]        _raw_spin_lock_irqsave+0x44/0x80
  [   32.833696]        task_rq_lock+0x2c/0xa0
  [   32.834182]        task_sched_runtime+0x59/0xd0
  [   32.834721]        thread_group_cputime+0x250/0x270
  [   32.835304]        thread_group_cputime_adjusted+0x2e/0x70
  [   32.835959]        do_task_stat+0x8a7/0xb80
  [   32.836461]        proc_single_show+0x51/0xb0
  ...
  [   32.839512] -> #0 (&(&sighand->siglock)->rlock){....}:
  [   32.840275]        __lock_acquire+0x1358/0x1a20
  [   32.840826]        lock_acquire+0xc7/0x1d0
  [   32.841309]        _raw_spin_lock_irqsave+0x44/0x80
  [   32.841916]        __lock_task_sighand+0x79/0x160
  [   32.842465]        do_send_sig_info+0x35/0x90
  [   32.842977]        bpf_send_signal+0xa/0x10
  [   32.843464]        bpf_prog_bc13ed9e4d3163e3_send_signal_tp_sched+0x465/0x1000
  [   32.844301]        trace_call_bpf+0x115/0x270
  [   32.844809]        perf_trace_run_bpf_submit+0x4a/0xc0
  [   32.845411]        perf_trace_sched_switch+0x10f/0x180
  [   32.846014]        __schedule+0x45d/0x880
  [   32.846483]        schedule+0x5f/0xd0
  ...

  [   32.853148] Chain exists of:
  [   32.853148]   &(&sighand->siglock)->rlock --> &p->pi_lock --> &rq->lock
  [   32.853148]
  [   32.854451]  Possible unsafe locking scenario:
  [   32.854451]
  [   32.855173]        CPU0                    CPU1
  [   32.855745]        ----                    ----
  [   32.856278]   lock(&rq->lock);
  [   32.856671]                                lock(&p->pi_lock);
  [   32.857332]                                lock(&rq->lock);
  [   32.857999]   lock(&(&sighand->siglock)->rlock);

  Deadlock happens on CPU0 when it tries to acquire &sighand->siglock
  but it has been held by CPU1 and CPU1 tries to grab &rq->lock
  and cannot get it.

  This is not exactly the callstack in our production environment,
  but sympotom is similar and both locks are using spin_lock_irqsave()
  to acquire the lock, and both involves rq_lock. The fix to delay
  sending signal when irq is disabled also fixed this issue.

Signed-off-by: Yonghong Song <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Cc: Song Liu <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
anthraxx pushed a commit that referenced this pull request Apr 18, 2020
[ Upstream commit 1bc7896 ]

When experimenting with bpf_send_signal() helper in our production
environment (5.2 based), we experienced a deadlock in NMI mode:
   #5 [ffffc9002219f770] queued_spin_lock_slowpath at ffffffff8110be24
   #6 [ffffc9002219f770] _raw_spin_lock_irqsave at ffffffff81a43012
   #7 [ffffc9002219f780] try_to_wake_up at ffffffff810e7ecd
   #8 [ffffc9002219f7e0] signal_wake_up_state at ffffffff810c7b55
   #9 [ffffc9002219f7f0] __send_signal at ffffffff810c8602
  #10 [ffffc9002219f830] do_send_sig_info at ffffffff810ca31a
  #11 [ffffc9002219f868] bpf_send_signal at ffffffff8119d227
  #12 [ffffc9002219f988] bpf_overflow_handler at ffffffff811d4140
  #13 [ffffc9002219f9e0] __perf_event_overflow at ffffffff811d68cf
  #14 [ffffc9002219fa10] perf_swevent_overflow at ffffffff811d6a09
  #15 [ffffc9002219fa38] ___perf_sw_event at ffffffff811e0f47
  #16 [ffffc9002219fc30] __schedule at ffffffff81a3e04d
  #17 [ffffc9002219fc90] schedule at ffffffff81a3e219
  #18 [ffffc9002219fca0] futex_wait_queue_me at ffffffff8113d1b9
  #19 [ffffc9002219fcd8] futex_wait at ffffffff8113e529
  #20 [ffffc9002219fdf0] do_futex at ffffffff8113ffbc
  #21 [ffffc9002219fec0] __x64_sys_futex at ffffffff81140d1c
  #22 [ffffc9002219ff38] do_syscall_64 at ffffffff81002602
  #23 [ffffc9002219ff50] entry_SYSCALL_64_after_hwframe at ffffffff81c00068

The above call stack is actually very similar to an issue
reported by Commit eac9153 ("bpf/stackmap: Fix deadlock with
rq_lock in bpf_get_stack()") by Song Liu. The only difference is
bpf_send_signal() helper instead of bpf_get_stack() helper.

The above deadlock is triggered with a perf_sw_event.
Similar to Commit eac9153, the below almost identical reproducer
used tracepoint point sched/sched_switch so the issue can be easily caught.
  /* stress_test.c */
  #include <stdio.h>
  #include <stdlib.h>
  #include <sys/mman.h>
  #include <pthread.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <fcntl.h>

  #define THREAD_COUNT 1000
  char *filename;
  void *worker(void *p)
  {
        void *ptr;
        int fd;
        char *pptr;

        fd = open(filename, O_RDONLY);
        if (fd < 0)
                return NULL;
        while (1) {
                struct timespec ts = {0, 1000 + rand() % 2000};

                ptr = mmap(NULL, 4096 * 64, PROT_READ, MAP_PRIVATE, fd, 0);
                usleep(1);
                if (ptr == MAP_FAILED) {
                        printf("failed to mmap\n");
                        break;
                }
                munmap(ptr, 4096 * 64);
                usleep(1);
                pptr = malloc(1);
                usleep(1);
                pptr[0] = 1;
                usleep(1);
                free(pptr);
                usleep(1);
                nanosleep(&ts, NULL);
        }
        close(fd);
        return NULL;
  }

  int main(int argc, char *argv[])
  {
        void *ptr;
        int i;
        pthread_t threads[THREAD_COUNT];

        if (argc < 2)
                return 0;

        filename = argv[1];

        for (i = 0; i < THREAD_COUNT; i++) {
                if (pthread_create(threads + i, NULL, worker, NULL)) {
                        fprintf(stderr, "Error creating thread\n");
                        return 0;
                }
        }

        for (i = 0; i < THREAD_COUNT; i++)
                pthread_join(threads[i], NULL);
        return 0;
  }
and the following command:
  1. run `stress_test /bin/ls` in one windown
  2. hack bcc trace.py with the following change:
#     --- a/tools/trace.py
#     +++ b/tools/trace.py
     @@ -513,6 +513,7 @@ BPF_PERF_OUTPUT(%s);
              __data.tgid = __tgid;
              __data.pid = __pid;
              bpf_get_current_comm(&__data.comm, sizeof(__data.comm));
     +        bpf_send_signal(10);
      %s
      %s
              %s.perf_submit(%s, &__data, sizeof(__data));
  3. in a different window run
     ./trace.py -p $(pidof stress_test) t:sched:sched_switch

The deadlock can be reproduced in our production system.

Similar to Song's fix, the fix is to delay sending signal if
irqs is disabled to avoid deadlocks involving with rq_lock.
With this change, my above stress-test in our production system
won't cause deadlock any more.

I also implemented a scale-down version of reproducer in the
selftest (a subsequent commit). With latest bpf-next,
it complains for the following potential deadlock.
  [   32.832450] -> #1 (&p->pi_lock){-.-.}:
  [   32.833100]        _raw_spin_lock_irqsave+0x44/0x80
  [   32.833696]        task_rq_lock+0x2c/0xa0
  [   32.834182]        task_sched_runtime+0x59/0xd0
  [   32.834721]        thread_group_cputime+0x250/0x270
  [   32.835304]        thread_group_cputime_adjusted+0x2e/0x70
  [   32.835959]        do_task_stat+0x8a7/0xb80
  [   32.836461]        proc_single_show+0x51/0xb0
  ...
  [   32.839512] -> #0 (&(&sighand->siglock)->rlock){....}:
  [   32.840275]        __lock_acquire+0x1358/0x1a20
  [   32.840826]        lock_acquire+0xc7/0x1d0
  [   32.841309]        _raw_spin_lock_irqsave+0x44/0x80
  [   32.841916]        __lock_task_sighand+0x79/0x160
  [   32.842465]        do_send_sig_info+0x35/0x90
  [   32.842977]        bpf_send_signal+0xa/0x10
  [   32.843464]        bpf_prog_bc13ed9e4d3163e3_send_signal_tp_sched+0x465/0x1000
  [   32.844301]        trace_call_bpf+0x115/0x270
  [   32.844809]        perf_trace_run_bpf_submit+0x4a/0xc0
  [   32.845411]        perf_trace_sched_switch+0x10f/0x180
  [   32.846014]        __schedule+0x45d/0x880
  [   32.846483]        schedule+0x5f/0xd0
  ...

  [   32.853148] Chain exists of:
  [   32.853148]   &(&sighand->siglock)->rlock --> &p->pi_lock --> &rq->lock
  [   32.853148]
  [   32.854451]  Possible unsafe locking scenario:
  [   32.854451]
  [   32.855173]        CPU0                    CPU1
  [   32.855745]        ----                    ----
  [   32.856278]   lock(&rq->lock);
  [   32.856671]                                lock(&p->pi_lock);
  [   32.857332]                                lock(&rq->lock);
  [   32.857999]   lock(&(&sighand->siglock)->rlock);

  Deadlock happens on CPU0 when it tries to acquire &sighand->siglock
  but it has been held by CPU1 and CPU1 tries to grab &rq->lock
  and cannot get it.

  This is not exactly the callstack in our production environment,
  but sympotom is similar and both locks are using spin_lock_irqsave()
  to acquire the lock, and both involves rq_lock. The fix to delay
  sending signal when irq is disabled also fixed this issue.

Signed-off-by: Yonghong Song <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Cc: Song Liu <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx pushed a commit that referenced this pull request Apr 18, 2020
[ Upstream commit 1bc7896 ]

When experimenting with bpf_send_signal() helper in our production
environment (5.2 based), we experienced a deadlock in NMI mode:
   #5 [ffffc9002219f770] queued_spin_lock_slowpath at ffffffff8110be24
   #6 [ffffc9002219f770] _raw_spin_lock_irqsave at ffffffff81a43012
   #7 [ffffc9002219f780] try_to_wake_up at ffffffff810e7ecd
   #8 [ffffc9002219f7e0] signal_wake_up_state at ffffffff810c7b55
   #9 [ffffc9002219f7f0] __send_signal at ffffffff810c8602
  #10 [ffffc9002219f830] do_send_sig_info at ffffffff810ca31a
  #11 [ffffc9002219f868] bpf_send_signal at ffffffff8119d227
  #12 [ffffc9002219f988] bpf_overflow_handler at ffffffff811d4140
  #13 [ffffc9002219f9e0] __perf_event_overflow at ffffffff811d68cf
  #14 [ffffc9002219fa10] perf_swevent_overflow at ffffffff811d6a09
  #15 [ffffc9002219fa38] ___perf_sw_event at ffffffff811e0f47
  #16 [ffffc9002219fc30] __schedule at ffffffff81a3e04d
  #17 [ffffc9002219fc90] schedule at ffffffff81a3e219
  #18 [ffffc9002219fca0] futex_wait_queue_me at ffffffff8113d1b9
  #19 [ffffc9002219fcd8] futex_wait at ffffffff8113e529
  #20 [ffffc9002219fdf0] do_futex at ffffffff8113ffbc
  #21 [ffffc9002219fec0] __x64_sys_futex at ffffffff81140d1c
  #22 [ffffc9002219ff38] do_syscall_64 at ffffffff81002602
  #23 [ffffc9002219ff50] entry_SYSCALL_64_after_hwframe at ffffffff81c00068

The above call stack is actually very similar to an issue
reported by Commit eac9153 ("bpf/stackmap: Fix deadlock with
rq_lock in bpf_get_stack()") by Song Liu. The only difference is
bpf_send_signal() helper instead of bpf_get_stack() helper.

The above deadlock is triggered with a perf_sw_event.
Similar to Commit eac9153, the below almost identical reproducer
used tracepoint point sched/sched_switch so the issue can be easily caught.
  /* stress_test.c */
  #include <stdio.h>
  #include <stdlib.h>
  #include <sys/mman.h>
  #include <pthread.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <fcntl.h>

  #define THREAD_COUNT 1000
  char *filename;
  void *worker(void *p)
  {
        void *ptr;
        int fd;
        char *pptr;

        fd = open(filename, O_RDONLY);
        if (fd < 0)
                return NULL;
        while (1) {
                struct timespec ts = {0, 1000 + rand() % 2000};

                ptr = mmap(NULL, 4096 * 64, PROT_READ, MAP_PRIVATE, fd, 0);
                usleep(1);
                if (ptr == MAP_FAILED) {
                        printf("failed to mmap\n");
                        break;
                }
                munmap(ptr, 4096 * 64);
                usleep(1);
                pptr = malloc(1);
                usleep(1);
                pptr[0] = 1;
                usleep(1);
                free(pptr);
                usleep(1);
                nanosleep(&ts, NULL);
        }
        close(fd);
        return NULL;
  }

  int main(int argc, char *argv[])
  {
        void *ptr;
        int i;
        pthread_t threads[THREAD_COUNT];

        if (argc < 2)
                return 0;

        filename = argv[1];

        for (i = 0; i < THREAD_COUNT; i++) {
                if (pthread_create(threads + i, NULL, worker, NULL)) {
                        fprintf(stderr, "Error creating thread\n");
                        return 0;
                }
        }

        for (i = 0; i < THREAD_COUNT; i++)
                pthread_join(threads[i], NULL);
        return 0;
  }
and the following command:
  1. run `stress_test /bin/ls` in one windown
  2. hack bcc trace.py with the following change:
#     --- a/tools/trace.py
#     +++ b/tools/trace.py
     @@ -513,6 +513,7 @@ BPF_PERF_OUTPUT(%s);
              __data.tgid = __tgid;
              __data.pid = __pid;
              bpf_get_current_comm(&__data.comm, sizeof(__data.comm));
     +        bpf_send_signal(10);
      %s
      %s
              %s.perf_submit(%s, &__data, sizeof(__data));
  3. in a different window run
     ./trace.py -p $(pidof stress_test) t:sched:sched_switch

The deadlock can be reproduced in our production system.

Similar to Song's fix, the fix is to delay sending signal if
irqs is disabled to avoid deadlocks involving with rq_lock.
With this change, my above stress-test in our production system
won't cause deadlock any more.

I also implemented a scale-down version of reproducer in the
selftest (a subsequent commit). With latest bpf-next,
it complains for the following potential deadlock.
  [   32.832450] -> #1 (&p->pi_lock){-.-.}:
  [   32.833100]        _raw_spin_lock_irqsave+0x44/0x80
  [   32.833696]        task_rq_lock+0x2c/0xa0
  [   32.834182]        task_sched_runtime+0x59/0xd0
  [   32.834721]        thread_group_cputime+0x250/0x270
  [   32.835304]        thread_group_cputime_adjusted+0x2e/0x70
  [   32.835959]        do_task_stat+0x8a7/0xb80
  [   32.836461]        proc_single_show+0x51/0xb0
  ...
  [   32.839512] -> #0 (&(&sighand->siglock)->rlock){....}:
  [   32.840275]        __lock_acquire+0x1358/0x1a20
  [   32.840826]        lock_acquire+0xc7/0x1d0
  [   32.841309]        _raw_spin_lock_irqsave+0x44/0x80
  [   32.841916]        __lock_task_sighand+0x79/0x160
  [   32.842465]        do_send_sig_info+0x35/0x90
  [   32.842977]        bpf_send_signal+0xa/0x10
  [   32.843464]        bpf_prog_bc13ed9e4d3163e3_send_signal_tp_sched+0x465/0x1000
  [   32.844301]        trace_call_bpf+0x115/0x270
  [   32.844809]        perf_trace_run_bpf_submit+0x4a/0xc0
  [   32.845411]        perf_trace_sched_switch+0x10f/0x180
  [   32.846014]        __schedule+0x45d/0x880
  [   32.846483]        schedule+0x5f/0xd0
  ...

  [   32.853148] Chain exists of:
  [   32.853148]   &(&sighand->siglock)->rlock --> &p->pi_lock --> &rq->lock
  [   32.853148]
  [   32.854451]  Possible unsafe locking scenario:
  [   32.854451]
  [   32.855173]        CPU0                    CPU1
  [   32.855745]        ----                    ----
  [   32.856278]   lock(&rq->lock);
  [   32.856671]                                lock(&p->pi_lock);
  [   32.857332]                                lock(&rq->lock);
  [   32.857999]   lock(&(&sighand->siglock)->rlock);

  Deadlock happens on CPU0 when it tries to acquire &sighand->siglock
  but it has been held by CPU1 and CPU1 tries to grab &rq->lock
  and cannot get it.

  This is not exactly the callstack in our production environment,
  but sympotom is similar and both locks are using spin_lock_irqsave()
  to acquire the lock, and both involves rq_lock. The fix to delay
  sending signal when irq is disabled also fixed this issue.

Signed-off-by: Yonghong Song <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Cc: Song Liu <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx pushed a commit that referenced this pull request Apr 18, 2020
[ Upstream commit 5737cfe ]

Phy for slot 0 and 1 is shared and handled properly in slot 0.
If there is only one port in use,(slot 0) we shall not call the
'phy_power_off' function with an invalid slot because kernel
will crash with an unaligned access fault like the following:

mt7621-pci 1e140000.pcie: Error applying setting, reverse things back
mt7621-pci-phy 1e149000.pcie-phy: PHY for 0xbe149000 (dual port = 1)
mt7621-pci-phy 1e14a000.pcie-phy: PHY for 0xbe14a000 (dual port = 0)
mt7621-pci-phy 1e149000.pcie-phy: Xtal is 40MHz
mt7621-pci-phy 1e14a000.pcie-phy: Xtal is 40MHz
mt7621-pci 1e140000.pcie: pcie1 no card, disable it (RST & CLK)
Unhandled kernel unaligned access[#1]:
CPU: 3 PID: 111 Comm: kworker/3:2 Not tainted 5.6.0-rc3-00347-g825c6f470c62-dirty #9
Workqueue: events deferred_probe_work_func
$ 0   : 00000000 00000001 5f60d043 8fe1ba80
$ 4   : 0000010d 01eb9000 00000000 00000000
$ 8   : 294b4c00 80940000 00000008 000000ce
$12   : 2e303030 00000000 00000000 65696370
$16   : ffffffed 0000010d 8e373cd0 8214c1e0
$20   : 00000000 82144c80 82144680 8214c250
$24   : 00000018 803ef8f4
$28   : 8e372000 8e373c60 8214c080 803940e8
Hi    : 00000125
Lo    : 122f2000
epc   : 807b3328 mutex_lock+0x8/0x44
ra    : 803940e8 phy_power_off+0x28/0xb0
Status: 1100fc03        KERNEL EXL IE
Cause : 00800010 (ExcCode 04)
BadVA : 0000010d
PrId  : 0001992f (MIPS 1004Kc)
Modules linked in:
Process kworker/3:2 (pid: 111, threadinfo=(ptrval), task=(ptrval), tls=00000000)
Stack : 8e373cd0 803fe4f4 8e372000 8e373c90 8214c080 804fde1c 8e373c98 808d62f4
         8e373c78 00000000 8214c254 804fe648 1e160000 804f27b8 00000001 808d62f4
         00000000 00000001 8214c228 808d62f4 80930000 809a0000 8fd47e10 808d63d4
         808d62d4 8fd47e10 808d0000 808d0000 8e373cd0 8e373cd0 809e2a74 809db510
         809db510 00000006 00000001 00000000 00000000 00000000 01000000 1e1440ff
         ...
Call Trace:
[<807b3328>] mutex_lock+0x8/0x44
[<803940e8>] phy_power_off+0x28/0xb0
[<804fe648>] mt7621_pci_probe+0xc20/0xd18
[<80402ab8>] platform_drv_probe+0x40/0x94
[<80400a74>] really_probe+0x104/0x364
[<803feb74>] bus_for_each_drv+0x84/0xdc
[<80400924>] __device_attach+0xdc/0x120
[<803ffb5c>] bus_probe_device+0xa0/0xbc
[<80400124>] deferred_probe_work_func+0x7c/0xbc
[<800420e8>] process_one_work+0x230/0x450
[<80042638>] worker_thread+0x330/0x5fc
[<80048eb0>] kthread+0x12c/0x134
[<80007438>] ret_from_kernel_thread+0x14/0x1c
Code: 2405000  27bdfff8  8f830000 <c0850000> 14a00005  00000000  00600825  e0810000  1020fffa

Fixes: bf516f4 ("staging: mt7621-pci: use only two phys from device tree")
Signed-off-by: Sergio Paracuellos <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Apr 23, 2020
commit e79b033 upstream.

Fix tcon use-after-free and NULL ptr deref.

Customer system crashes with the following kernel log:

[462233.169868] CIFS VFS: Cancelling wait for mid 4894753 cmd: 14       => a QUERY DIR
[462233.228045] CIFS VFS: cifs_put_smb_ses: Session Logoff failure rc=-4
[462233.305922] CIFS VFS: cifs_put_smb_ses: Session Logoff failure rc=-4
[462233.306205] CIFS VFS: cifs_put_smb_ses: Session Logoff failure rc=-4
[462233.347060] CIFS VFS: cifs_put_smb_ses: Session Logoff failure rc=-4
[462233.347107] CIFS VFS: Close unmatched open
[462233.347113] BUG: unable to handle kernel NULL pointer dereference at 0000000000000038
...
    [exception RIP: cifs_put_tcon+0xa0] (this is doing tcon->ses->server)
 #6 [...] smb2_cancelled_close_fid at ... [cifs]
 #7 [...] process_one_work at ...
 #8 [...] worker_thread at ...
 #9 [...] kthread at ...

The most likely explanation we have is:

* When we put the last reference of a tcon (refcount=0), we close the
  cached share root handle.
* If closing a handle is interrupted, SMB2_close() will
  queue a SMB2_close() in a work thread.
* The queued object keeps a tcon ref so we bump the tcon
  refcount, jumping from 0 to 1.
* We reach the end of cifs_put_tcon(), we free the tcon object despite
  it now having a refcount of 1.
* The queued work now runs, but the tcon, ses & server was freed in
  the meantime resulting in a crash.

THREAD 1
========
cifs_put_tcon                 => tcon refcount reach 0
  SMB2_tdis
   close_shroot_lease
    close_shroot_lease_locked => if cached root has lease && refcount = 0
     smb2_close_cached_fid    => if cached root valid
      SMB2_close              => retry close in a thread if interrupted
       smb2_handle_cancelled_close
        __smb2_handle_cancelled_close    => !! tcon refcount bump 0 => 1 !!
         INIT_WORK(&cancelled->work, smb2_cancelled_close_fid);
         queue_work(cifsiod_wq, &cancelled->work) => queue work
 tconInfoFree(tcon);    ==> freed!
 cifs_put_smb_ses(ses); ==> freed!

THREAD 2 (workqueue)
========
smb2_cancelled_close_fid
  SMB2_close(0, cancelled->tcon, ...); => use-after-free of tcon
  cifs_put_tcon(cancelled->tcon);      => tcon refcount reach 0 second time
  *CRASH*

Fixes: d919131 ("CIFS: Close cached root handle only if it has a lease")
Signed-off-by: Aurelien Aptel <[email protected]>
Signed-off-by: Steve French <[email protected]>
Reviewed-by: Pavel Shilovsky <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx pushed a commit that referenced this pull request May 26, 2020
This BUG halt was reported a while back, but the patch somehow got
missed:

PID: 2879   TASK: c16adaa0  CPU: 1   COMMAND: "sctpn"
 #0 [f418dd28] crash_kexec at c04a7d8c
 #1 [f418dd7c] oops_end at c0863e02
 #2 [f418dd90] do_invalid_op at c040aaca
 #3 [f418de28] error_code (via invalid_op) at c08631a5
    EAX: f34baac0  EBX: 00000090  ECX: f418deb0  EDX: f5542950  EBP: 00000000
    DS:  007b      ESI: f34ba800  ES:  007b      EDI: f418dea0  GS:  00e0
    CS:  0060      EIP: c046fa5e  ERR: ffffffff  EFLAGS: 00010286
 #4 [f418de5c] add_timer at c046fa5e
 #5 [f418de68] sctp_do_sm at f8db8c77 [sctp]
 #6 [f418df30] sctp_primitive_SHUTDOWN at f8dcc1b5 [sctp]
 #7 [f418df48] inet_shutdown at c080baf9
 #8 [f418df5c] sys_shutdown at c079eedf
 #9 [f418df70] sys_socketcall at c079fe88
    EAX: ffffffda  EBX: 0000000d  ECX: bfceea90  EDX: 0937af98
    DS:  007b      ESI: 0000000c  ES:  007b      EDI: b7150ae4
    SS:  007b      ESP: bfceea7c  EBP: bfceeaa8  GS:  0033
    CS:  0073      EIP: b775c424  ERR: 00000066  EFLAGS: 00000282

It appears that the side effect that starts the shutdown timer was processed
multiple times, which can happen as multiple paths can trigger it.  This of
course leads to the BUG halt in add_timer getting called.

Fix seems pretty straightforward, just check before the timer is added if its
already been started.  If it has mod the timer instead to min(current
expiration, new expiration)

Its been tested but not confirmed to fix the problem, as the issue has only
occured in production environments where test kernels are enjoined from being
installed.  It appears to be a sane fix to me though.  Also, recentely,
Jere found a reproducer posted on list to confirm that this resolves the
issues

Signed-off-by: Neil Horman <[email protected]>
CC: Vlad Yasevich <[email protected]>
CC: "David S. Miller" <[email protected]>
CC: [email protected]
CC: [email protected]
CC: [email protected]
Acked-by: Marcelo Ricardo Leitner <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
anthraxx pushed a commit that referenced this pull request Jun 19, 2025
[ Upstream commit 88f7f56 ]

When a bio with REQ_PREFLUSH is submitted to dm, __send_empty_flush()
generates a flush_bio with REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC,
which causes the flush_bio to be throttled by wbt_wait().

An example from v5.4, similar problem also exists in upstream:

    crash> bt 2091206
    PID: 2091206  TASK: ffff2050df92a300  CPU: 109  COMMAND: "kworker/u260:0"
     #0 [ffff800084a2f7f0] __switch_to at ffff80004008aeb8
     #1 [ffff800084a2f820] __schedule at ffff800040bfa0c4
     #2 [ffff800084a2f880] schedule at ffff800040bfa4b4
     #3 [ffff800084a2f8a0] io_schedule at ffff800040bfa9c4
     #4 [ffff800084a2f8c0] rq_qos_wait at ffff8000405925bc
     #5 [ffff800084a2f940] wbt_wait at ffff8000405bb3a0
     #6 [ffff800084a2f9a0] __rq_qos_throttle at ffff800040592254
     #7 [ffff800084a2f9c0] blk_mq_make_request at ffff80004057cf38
     #8 [ffff800084a2fa60] generic_make_request at ffff800040570138
     #9 [ffff800084a2fae0] submit_bio at ffff8000405703b4
    #10 [ffff800084a2fb50] xlog_write_iclog at ffff800001280834 [xfs]
    #11 [ffff800084a2fbb0] xlog_sync at ffff800001280c3c [xfs]
    #12 [ffff800084a2fbf0] xlog_state_release_iclog at ffff800001280df4 [xfs]
    #13 [ffff800084a2fc10] xlog_write at ffff80000128203c [xfs]
    #14 [ffff800084a2fcd0] xlog_cil_push at ffff8000012846dc [xfs]
    #15 [ffff800084a2fda0] xlog_cil_push_work at ffff800001284a2c [xfs]
    #16 [ffff800084a2fdb0] process_one_work at ffff800040111d08
    #17 [ffff800084a2fe00] worker_thread at ffff8000401121cc
    #18 [ffff800084a2fe70] kthread at ffff800040118de4

After commit 2def284 ("xfs: don't allow log IO to be throttled"),
the metadata submitted by xlog_write_iclog() should not be throttled.
But due to the existence of the dm layer, throttling flush_bio indirectly
causes the metadata bio to be throttled.

Fix this by conditionally adding REQ_IDLE to flush_bio.bi_opf, which makes
wbt_should_throttle() return false to avoid wbt_wait().

Signed-off-by: Jinliang Zheng <[email protected]>
Reviewed-by: Tianxiang Peng <[email protected]>
Reviewed-by: Hao Peng <[email protected]>
Signed-off-by: Mikulas Patocka <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jun 19, 2025
[ Upstream commit f34621f ]

According to the board schematics the enable pin of this regulator is
connected to gpio line #9 of the first instance of the TCA9539
GPIO expander, so adjust it.

Signed-off-by: Diogo Ivo <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Thierry Reding <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jun 19, 2025
[ Upstream commit 88f7f56 ]

When a bio with REQ_PREFLUSH is submitted to dm, __send_empty_flush()
generates a flush_bio with REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC,
which causes the flush_bio to be throttled by wbt_wait().

An example from v5.4, similar problem also exists in upstream:

    crash> bt 2091206
    PID: 2091206  TASK: ffff2050df92a300  CPU: 109  COMMAND: "kworker/u260:0"
     #0 [ffff800084a2f7f0] __switch_to at ffff80004008aeb8
     #1 [ffff800084a2f820] __schedule at ffff800040bfa0c4
     #2 [ffff800084a2f880] schedule at ffff800040bfa4b4
     #3 [ffff800084a2f8a0] io_schedule at ffff800040bfa9c4
     #4 [ffff800084a2f8c0] rq_qos_wait at ffff8000405925bc
     #5 [ffff800084a2f940] wbt_wait at ffff8000405bb3a0
     #6 [ffff800084a2f9a0] __rq_qos_throttle at ffff800040592254
     #7 [ffff800084a2f9c0] blk_mq_make_request at ffff80004057cf38
     #8 [ffff800084a2fa60] generic_make_request at ffff800040570138
     #9 [ffff800084a2fae0] submit_bio at ffff8000405703b4
    #10 [ffff800084a2fb50] xlog_write_iclog at ffff800001280834 [xfs]
    #11 [ffff800084a2fbb0] xlog_sync at ffff800001280c3c [xfs]
    #12 [ffff800084a2fbf0] xlog_state_release_iclog at ffff800001280df4 [xfs]
    #13 [ffff800084a2fc10] xlog_write at ffff80000128203c [xfs]
    #14 [ffff800084a2fcd0] xlog_cil_push at ffff8000012846dc [xfs]
    #15 [ffff800084a2fda0] xlog_cil_push_work at ffff800001284a2c [xfs]
    #16 [ffff800084a2fdb0] process_one_work at ffff800040111d08
    #17 [ffff800084a2fe00] worker_thread at ffff8000401121cc
    #18 [ffff800084a2fe70] kthread at ffff800040118de4

After commit 2def284 ("xfs: don't allow log IO to be throttled"),
the metadata submitted by xlog_write_iclog() should not be throttled.
But due to the existence of the dm layer, throttling flush_bio indirectly
causes the metadata bio to be throttled.

Fix this by conditionally adding REQ_IDLE to flush_bio.bi_opf, which makes
wbt_should_throttle() return false to avoid wbt_wait().

Signed-off-by: Jinliang Zheng <[email protected]>
Reviewed-by: Tianxiang Peng <[email protected]>
Reviewed-by: Hao Peng <[email protected]>
Signed-off-by: Mikulas Patocka <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jun 19, 2025
commit 9857af0 upstream.

Commit e77aff5 ("binderfs: fix use-after-free in binder_devices")
addressed a use-after-free where devices could be released without first
being removed from the binder_devices list. However, there is a similar
path in binder_free_proc() that was missed:

  ==================================================================
  BUG: KASAN: slab-use-after-free in binder_remove_device+0xd4/0x100
  Write of size 8 at addr ffff0000c773b900 by task umount/467
  CPU: 12 UID: 0 PID: 467 Comm: umount Not tainted 6.15.0-rc7-00138-g57483a362741 #9 PREEMPT
  Hardware name: linux,dummy-virt (DT)
  Call trace:
   binder_remove_device+0xd4/0x100
   binderfs_evict_inode+0x230/0x2f0
   evict+0x25c/0x5dc
   iput+0x304/0x480
   dentry_unlink_inode+0x208/0x46c
   __dentry_kill+0x154/0x530
   [...]

  Allocated by task 463:
   __kmalloc_cache_noprof+0x13c/0x324
   binderfs_binder_device_create.isra.0+0x138/0xa60
   binder_ctl_ioctl+0x1ac/0x230
  [...]

  Freed by task 215:
   kfree+0x184/0x31c
   binder_proc_dec_tmpref+0x33c/0x4ac
   binder_deferred_func+0xc10/0x1108
   process_one_work+0x520/0xba4
  [...]
  ==================================================================

Call binder_remove_device() within binder_free_proc() to ensure the
device is removed from the binder_devices list before being kfreed.

Cc: [email protected]
Fixes: 12d909c ("binderfs: add new binder devices to binder_devices")
Reported-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=4af454407ec393de51d6
Tested-by: [email protected]
Signed-off-by: Carlos Llamas <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx pushed a commit that referenced this pull request Jun 19, 2025
[ Upstream commit ee684de ]

As shown in [1], it is possible to corrupt a BPF ELF file such that
arbitrary BPF instructions are loaded by libbpf. This can be done by
setting a symbol (BPF program) section offset to a large (unsigned)
number such that <section start + symbol offset> overflows and points
before the section data in the memory.

Consider the situation below where:
- prog_start = sec_start + symbol_offset    <-- size_t overflow here
- prog_end   = prog_start + prog_size

    prog_start        sec_start        prog_end        sec_end
        |                |                 |              |
        v                v                 v              v
    .....................|################################|............

The report in [1] also provides a corrupted BPF ELF which can be used as
a reproducer:

    $ readelf -S crash
    Section Headers:
      [Nr] Name              Type             Address           Offset
           Size              EntSize          Flags  Link  Info  Align
    ...
      [ 2] uretprobe.mu[...] PROGBITS         0000000000000000  00000040
           0000000000000068  0000000000000000  AX       0     0     8

    $ readelf -s crash
    Symbol table '.symtab' contains 8 entries:
       Num:    Value          Size Type    Bind   Vis      Ndx Name
    ...
         6: ffffffffffffffb8   104 FUNC    GLOBAL DEFAULT    2 handle_tp

Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will
point before the actual memory where section 2 is allocated.

This is also reported by AddressSanitizer:

    =================================================================
    ==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490
    READ of size 104 at 0x7c7302fe0000 thread T0
        #0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76)
        #1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856
        #2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928
        #3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930
        #4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067
        #5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090
        #6 0x000000400c16 in main /poc/poc.c:8
        #7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4)
        #8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667)
        #9 0x000000400b34 in _start (/poc/poc+0x400b34)

    0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8)
    allocated by thread T0 here:
        #0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b)
        #1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600)
        #2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018)
        #3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740

The problem here is that currently, libbpf only checks that the program
end is within the section bounds. There used to be a check
`while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was
removed by commit 6245947 ("libbpf: Allow gaps in BPF program
sections to support overriden weak functions").

Add a check for detecting the overflow of `sec_off + prog_sz` to
bpf_object__init_prog to fix this issue.

[1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md

Fixes: 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions")
Reported-by: lmarch2 <[email protected]>
Signed-off-by: Viktor Malik <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Reviewed-by: Shung-Hsi Yu <[email protected]>
Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md
Link: https://lore.kernel.org/bpf/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jun 19, 2025
[ Upstream commit ee684de ]

As shown in [1], it is possible to corrupt a BPF ELF file such that
arbitrary BPF instructions are loaded by libbpf. This can be done by
setting a symbol (BPF program) section offset to a large (unsigned)
number such that <section start + symbol offset> overflows and points
before the section data in the memory.

Consider the situation below where:
- prog_start = sec_start + symbol_offset    <-- size_t overflow here
- prog_end   = prog_start + prog_size

    prog_start        sec_start        prog_end        sec_end
        |                |                 |              |
        v                v                 v              v
    .....................|################################|............

The report in [1] also provides a corrupted BPF ELF which can be used as
a reproducer:

    $ readelf -S crash
    Section Headers:
      [Nr] Name              Type             Address           Offset
           Size              EntSize          Flags  Link  Info  Align
    ...
      [ 2] uretprobe.mu[...] PROGBITS         0000000000000000  00000040
           0000000000000068  0000000000000000  AX       0     0     8

    $ readelf -s crash
    Symbol table '.symtab' contains 8 entries:
       Num:    Value          Size Type    Bind   Vis      Ndx Name
    ...
         6: ffffffffffffffb8   104 FUNC    GLOBAL DEFAULT    2 handle_tp

Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will
point before the actual memory where section 2 is allocated.

This is also reported by AddressSanitizer:

    =================================================================
    ==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490
    READ of size 104 at 0x7c7302fe0000 thread T0
        #0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76)
        #1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856
        #2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928
        #3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930
        #4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067
        #5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090
        #6 0x000000400c16 in main /poc/poc.c:8
        #7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4)
        #8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667)
        #9 0x000000400b34 in _start (/poc/poc+0x400b34)

    0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8)
    allocated by thread T0 here:
        #0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b)
        #1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600)
        #2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018)
        #3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740

The problem here is that currently, libbpf only checks that the program
end is within the section bounds. There used to be a check
`while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was
removed by commit 6245947 ("libbpf: Allow gaps in BPF program
sections to support overriden weak functions").

Add a check for detecting the overflow of `sec_off + prog_sz` to
bpf_object__init_prog to fix this issue.

[1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md

Fixes: 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions")
Reported-by: lmarch2 <[email protected]>
Signed-off-by: Viktor Malik <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Reviewed-by: Shung-Hsi Yu <[email protected]>
Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md
Link: https://lore.kernel.org/bpf/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jul 11, 2025
[ Upstream commit ee684de ]

As shown in [1], it is possible to corrupt a BPF ELF file such that
arbitrary BPF instructions are loaded by libbpf. This can be done by
setting a symbol (BPF program) section offset to a large (unsigned)
number such that <section start + symbol offset> overflows and points
before the section data in the memory.

Consider the situation below where:
- prog_start = sec_start + symbol_offset    <-- size_t overflow here
- prog_end   = prog_start + prog_size

    prog_start        sec_start        prog_end        sec_end
        |                |                 |              |
        v                v                 v              v
    .....................|################################|............

The report in [1] also provides a corrupted BPF ELF which can be used as
a reproducer:

    $ readelf -S crash
    Section Headers:
      [Nr] Name              Type             Address           Offset
           Size              EntSize          Flags  Link  Info  Align
    ...
      [ 2] uretprobe.mu[...] PROGBITS         0000000000000000  00000040
           0000000000000068  0000000000000000  AX       0     0     8

    $ readelf -s crash
    Symbol table '.symtab' contains 8 entries:
       Num:    Value          Size Type    Bind   Vis      Ndx Name
    ...
         6: ffffffffffffffb8   104 FUNC    GLOBAL DEFAULT    2 handle_tp

Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will
point before the actual memory where section 2 is allocated.

This is also reported by AddressSanitizer:

    =================================================================
    ==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490
    READ of size 104 at 0x7c7302fe0000 thread T0
        #0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76)
        #1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856
        #2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928
        #3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930
        #4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067
        #5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090
        #6 0x000000400c16 in main /poc/poc.c:8
        #7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4)
        #8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667)
        #9 0x000000400b34 in _start (/poc/poc+0x400b34)

    0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8)
    allocated by thread T0 here:
        #0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b)
        #1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600)
        #2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018)
        #3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740

The problem here is that currently, libbpf only checks that the program
end is within the section bounds. There used to be a check
`while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was
removed by commit 6245947 ("libbpf: Allow gaps in BPF program
sections to support overriden weak functions").

Add a check for detecting the overflow of `sec_off + prog_sz` to
bpf_object__init_prog to fix this issue.

[1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md

Fixes: 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions")
Reported-by: lmarch2 <[email protected]>
Signed-off-by: Viktor Malik <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Reviewed-by: Shung-Hsi Yu <[email protected]>
Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md
Link: https://lore.kernel.org/bpf/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jul 11, 2025
[ Upstream commit ee684de ]

As shown in [1], it is possible to corrupt a BPF ELF file such that
arbitrary BPF instructions are loaded by libbpf. This can be done by
setting a symbol (BPF program) section offset to a large (unsigned)
number such that <section start + symbol offset> overflows and points
before the section data in the memory.

Consider the situation below where:
- prog_start = sec_start + symbol_offset    <-- size_t overflow here
- prog_end   = prog_start + prog_size

    prog_start        sec_start        prog_end        sec_end
        |                |                 |              |
        v                v                 v              v
    .....................|################################|............

The report in [1] also provides a corrupted BPF ELF which can be used as
a reproducer:

    $ readelf -S crash
    Section Headers:
      [Nr] Name              Type             Address           Offset
           Size              EntSize          Flags  Link  Info  Align
    ...
      [ 2] uretprobe.mu[...] PROGBITS         0000000000000000  00000040
           0000000000000068  0000000000000000  AX       0     0     8

    $ readelf -s crash
    Symbol table '.symtab' contains 8 entries:
       Num:    Value          Size Type    Bind   Vis      Ndx Name
    ...
         6: ffffffffffffffb8   104 FUNC    GLOBAL DEFAULT    2 handle_tp

Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will
point before the actual memory where section 2 is allocated.

This is also reported by AddressSanitizer:

    =================================================================
    ==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490
    READ of size 104 at 0x7c7302fe0000 thread T0
        #0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76)
        #1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856
        #2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928
        #3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930
        #4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067
        #5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090
        #6 0x000000400c16 in main /poc/poc.c:8
        #7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4)
        #8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667)
        #9 0x000000400b34 in _start (/poc/poc+0x400b34)

    0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8)
    allocated by thread T0 here:
        #0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b)
        #1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600)
        #2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018)
        #3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740

The problem here is that currently, libbpf only checks that the program
end is within the section bounds. There used to be a check
`while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was
removed by commit 6245947 ("libbpf: Allow gaps in BPF program
sections to support overriden weak functions").

Add a check for detecting the overflow of `sec_off + prog_sz` to
bpf_object__init_prog to fix this issue.

[1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md

Fixes: 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions")
Reported-by: lmarch2 <[email protected]>
Signed-off-by: Viktor Malik <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Reviewed-by: Shung-Hsi Yu <[email protected]>
Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md
Link: https://lore.kernel.org/bpf/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jul 11, 2025
[ Upstream commit 6c7ffc9 ]

Remove redundant netif_napi_del() call from disconnect path.

A WARN may be triggered in __netif_napi_del_locked() during USB device
disconnect:

  WARNING: CPU: 0 PID: 11 at net/core/dev.c:7417 __netif_napi_del_locked+0x2b4/0x350

This happens because netif_napi_del() is called in the disconnect path while
NAPI is still enabled. However, it is not necessary to call netif_napi_del()
explicitly, since unregister_netdev() will handle NAPI teardown automatically
and safely. Removing the redundant call avoids triggering the warning.

Full trace:
 lan78xx 1-1:1.0 enu1: Failed to read register index 0x000000c4. ret = -ENODEV
 lan78xx 1-1:1.0 enu1: Failed to set MAC down with error -ENODEV
 lan78xx 1-1:1.0 enu1: Link is Down
 lan78xx 1-1:1.0 enu1: Failed to read register index 0x00000120. ret = -ENODEV
 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 11 at net/core/dev.c:7417 __netif_napi_del_locked+0x2b4/0x350
 Modules linked in: flexcan can_dev fuse
 CPU: 0 UID: 0 PID: 11 Comm: kworker/0:1 Not tainted 6.16.0-rc2-00624-ge926949dab03 #9 PREEMPT
 Hardware name: SKOV IMX8MP CPU revC - bd500 (DT)
 Workqueue: usb_hub_wq hub_event
 pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
 pc : __netif_napi_del_locked+0x2b4/0x350
 lr : __netif_napi_del_locked+0x7c/0x350
 sp : ffffffc085b673c0
 x29: ffffffc085b673c0 x28: ffffff800b7f2000 x27: ffffff800b7f20d8
 x26: ffffff80110bcf58 x25: ffffff80110bd978 x24: 1ffffff0022179eb
 x23: ffffff80110bc000 x22: ffffff800b7f5000 x21: ffffff80110bc000
 x20: ffffff80110bcf38 x19: ffffff80110bcf28 x18: dfffffc000000000
 x17: ffffffc081578940 x16: ffffffc08284cee0 x15: 0000000000000028
 x14: 0000000000000006 x13: 0000000000040000 x12: ffffffb0022179e8
 x11: 1ffffff0022179e7 x10: ffffffb0022179e7 x9 : dfffffc000000000
 x8 : 0000004ffdde8619 x7 : ffffff80110bcf3f x6 : 0000000000000001
 x5 : ffffff80110bcf38 x4 : ffffff80110bcf38 x3 : 0000000000000000
 x2 : 0000000000000000 x1 : 1ffffff0022179e7 x0 : 0000000000000000
 Call trace:
  __netif_napi_del_locked+0x2b4/0x350 (P)
  lan78xx_disconnect+0xf4/0x360
  usb_unbind_interface+0x158/0x718
  device_remove+0x100/0x150
  device_release_driver_internal+0x308/0x478
  device_release_driver+0x1c/0x30
  bus_remove_device+0x1a8/0x368
  device_del+0x2e0/0x7b0
  usb_disable_device+0x244/0x540
  usb_disconnect+0x220/0x758
  hub_event+0x105c/0x35e0
  process_one_work+0x760/0x17b0
  worker_thread+0x768/0xce8
  kthread+0x3bc/0x690
  ret_from_fork+0x10/0x20
 irq event stamp: 211604
 hardirqs last  enabled at (211603): [<ffffffc0828cc9ec>] _raw_spin_unlock_irqrestore+0x84/0x98
 hardirqs last disabled at (211604): [<ffffffc0828a9a84>] el1_dbg+0x24/0x80
 softirqs last  enabled at (211296): [<ffffffc080095f10>] handle_softirqs+0x820/0xbc8
 softirqs last disabled at (210993): [<ffffffc080010288>] __do_softirq+0x18/0x20
 ---[ end trace 0000000000000000 ]---
 lan78xx 1-1:1.0 enu1: failed to kill vid 0081/0

Fixes: ec4c7e1 ("lan78xx: Introduce NAPI polling support")
Suggested-by: Jakub Kicinski <[email protected]>
Signed-off-by: Oleksij Rempel <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jul 11, 2025
[ Upstream commit 6c7ffc9 ]

Remove redundant netif_napi_del() call from disconnect path.

A WARN may be triggered in __netif_napi_del_locked() during USB device
disconnect:

  WARNING: CPU: 0 PID: 11 at net/core/dev.c:7417 __netif_napi_del_locked+0x2b4/0x350

This happens because netif_napi_del() is called in the disconnect path while
NAPI is still enabled. However, it is not necessary to call netif_napi_del()
explicitly, since unregister_netdev() will handle NAPI teardown automatically
and safely. Removing the redundant call avoids triggering the warning.

Full trace:
 lan78xx 1-1:1.0 enu1: Failed to read register index 0x000000c4. ret = -ENODEV
 lan78xx 1-1:1.0 enu1: Failed to set MAC down with error -ENODEV
 lan78xx 1-1:1.0 enu1: Link is Down
 lan78xx 1-1:1.0 enu1: Failed to read register index 0x00000120. ret = -ENODEV
 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 11 at net/core/dev.c:7417 __netif_napi_del_locked+0x2b4/0x350
 Modules linked in: flexcan can_dev fuse
 CPU: 0 UID: 0 PID: 11 Comm: kworker/0:1 Not tainted 6.16.0-rc2-00624-ge926949dab03 #9 PREEMPT
 Hardware name: SKOV IMX8MP CPU revC - bd500 (DT)
 Workqueue: usb_hub_wq hub_event
 pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
 pc : __netif_napi_del_locked+0x2b4/0x350
 lr : __netif_napi_del_locked+0x7c/0x350
 sp : ffffffc085b673c0
 x29: ffffffc085b673c0 x28: ffffff800b7f2000 x27: ffffff800b7f20d8
 x26: ffffff80110bcf58 x25: ffffff80110bd978 x24: 1ffffff0022179eb
 x23: ffffff80110bc000 x22: ffffff800b7f5000 x21: ffffff80110bc000
 x20: ffffff80110bcf38 x19: ffffff80110bcf28 x18: dfffffc000000000
 x17: ffffffc081578940 x16: ffffffc08284cee0 x15: 0000000000000028
 x14: 0000000000000006 x13: 0000000000040000 x12: ffffffb0022179e8
 x11: 1ffffff0022179e7 x10: ffffffb0022179e7 x9 : dfffffc000000000
 x8 : 0000004ffdde8619 x7 : ffffff80110bcf3f x6 : 0000000000000001
 x5 : ffffff80110bcf38 x4 : ffffff80110bcf38 x3 : 0000000000000000
 x2 : 0000000000000000 x1 : 1ffffff0022179e7 x0 : 0000000000000000
 Call trace:
  __netif_napi_del_locked+0x2b4/0x350 (P)
  lan78xx_disconnect+0xf4/0x360
  usb_unbind_interface+0x158/0x718
  device_remove+0x100/0x150
  device_release_driver_internal+0x308/0x478
  device_release_driver+0x1c/0x30
  bus_remove_device+0x1a8/0x368
  device_del+0x2e0/0x7b0
  usb_disable_device+0x244/0x540
  usb_disconnect+0x220/0x758
  hub_event+0x105c/0x35e0
  process_one_work+0x760/0x17b0
  worker_thread+0x768/0xce8
  kthread+0x3bc/0x690
  ret_from_fork+0x10/0x20
 irq event stamp: 211604
 hardirqs last  enabled at (211603): [<ffffffc0828cc9ec>] _raw_spin_unlock_irqrestore+0x84/0x98
 hardirqs last disabled at (211604): [<ffffffc0828a9a84>] el1_dbg+0x24/0x80
 softirqs last  enabled at (211296): [<ffffffc080095f10>] handle_softirqs+0x820/0xbc8
 softirqs last disabled at (210993): [<ffffffc080010288>] __do_softirq+0x18/0x20
 ---[ end trace 0000000000000000 ]---
 lan78xx 1-1:1.0 enu1: failed to kill vid 0081/0

Fixes: ec4c7e1 ("lan78xx: Introduce NAPI polling support")
Suggested-by: Jakub Kicinski <[email protected]>
Signed-off-by: Oleksij Rempel <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jul 11, 2025
[ Upstream commit eedf3e3 ]

ACPICA commit 1c28da2242783579d59767617121035dafba18c3

This was originally done in NetBSD:
NetBSD/src@b69d1ac
and is the correct alternative to the smattering of `memcpy`s I
previously contributed to this repository.

This also sidesteps the newly strict checks added in UBSAN:
llvm/llvm-project@7926744

Before this change we see the following UBSAN stack trace in Fuchsia:

  #0    0x000021afcfdeca5e in acpi_rs_get_address_common(struct acpi_resource*, union aml_resource*) ../../third_party/acpica/source/components/resources/rsaddr.c:329 <platform-bus-x86.so>+0x6aca5e
  #1.2  0x000021982bc4af3c in ubsan_get_stack_trace() compiler-rt/lib/ubsan/ubsan_diag.cpp:41 <libclang_rt.asan.so>+0x41f3c
  #1.1  0x000021982bc4af3c in maybe_print_stack_trace() compiler-rt/lib/ubsan/ubsan_diag.cpp:51 <libclang_rt.asan.so>+0x41f3c
  #1    0x000021982bc4af3c in ~scoped_report() compiler-rt/lib/ubsan/ubsan_diag.cpp:395 <libclang_rt.asan.so>+0x41f3c
  #2    0x000021982bc4bb6f in handletype_mismatch_impl() compiler-rt/lib/ubsan/ubsan_handlers.cpp:137 <libclang_rt.asan.so>+0x42b6f
  #3    0x000021982bc4b723 in __ubsan_handle_type_mismatch_v1 compiler-rt/lib/ubsan/ubsan_handlers.cpp:142 <libclang_rt.asan.so>+0x42723
  #4    0x000021afcfdeca5e in acpi_rs_get_address_common(struct acpi_resource*, union aml_resource*) ../../third_party/acpica/source/components/resources/rsaddr.c:329 <platform-bus-x86.so>+0x6aca5e
  #5    0x000021afcfdf2089 in acpi_rs_convert_aml_to_resource(struct acpi_resource*, union aml_resource*, struct acpi_rsconvert_info*) ../../third_party/acpica/source/components/resources/rsmisc.c:355 <platform-bus-x86.so>+0x6b2089
  #6    0x000021afcfded169 in acpi_rs_convert_aml_to_resources(u8*, u32, u32, u8, void**) ../../third_party/acpica/source/components/resources/rslist.c:137 <platform-bus-x86.so>+0x6ad169
  #7    0x000021afcfe2d24a in acpi_ut_walk_aml_resources(struct acpi_walk_state*, u8*, acpi_size, acpi_walk_aml_callback, void**) ../../third_party/acpica/source/components/utilities/utresrc.c:237 <platform-bus-x86.so>+0x6ed24a
  #8    0x000021afcfde66b7 in acpi_rs_create_resource_list(union acpi_operand_object*, struct acpi_buffer*) ../../third_party/acpica/source/components/resources/rscreate.c:199 <platform-bus-x86.so>+0x6a66b7
  #9    0x000021afcfdf6979 in acpi_rs_get_method_data(acpi_handle, const char*, struct acpi_buffer*) ../../third_party/acpica/source/components/resources/rsutils.c:770 <platform-bus-x86.so>+0x6b6979
  #10   0x000021afcfdf708f in acpi_walk_resources(acpi_handle, char*, acpi_walk_resource_callback, void*) ../../third_party/acpica/source/components/resources/rsxface.c:731 <platform-bus-x86.so>+0x6b708f
  #11   0x000021afcfa95dcf in acpi::acpi_impl::walk_resources(acpi::acpi_impl*, acpi_handle, const char*, acpi::Acpi::resources_callable) ../../src/devices/board/lib/acpi/acpi-impl.cc:41 <platform-bus-x86.so>+0x355dcf
  #12   0x000021afcfaa8278 in acpi::device_builder::gather_resources(acpi::device_builder*, acpi::Acpi*, fidl::any_arena&, acpi::Manager*, acpi::device_builder::gather_resources_callback) ../../src/devices/board/lib/acpi/device-builder.cc:84 <platform-bus-x86.so>+0x368278
  #13   0x000021afcfbddb87 in acpi::Manager::configure_discovered_devices(acpi::Manager*) ../../src/devices/board/lib/acpi/manager.cc:75 <platform-bus-x86.so>+0x49db87
  #14   0x000021afcf99091d in publish_acpi_devices(acpi::Manager*, zx_device_t*, zx_device_t*) ../../src/devices/board/drivers/x86/acpi-nswalk.cc:95 <platform-bus-x86.so>+0x25091d
  #15   0x000021afcf9c1d4e in x86::X86::do_init(x86::X86*) ../../src/devices/board/drivers/x86/x86.cc:60 <platform-bus-x86.so>+0x281d4e
  #16   0x000021afcf9e33ad in λ(x86::X86::ddk_init::(anon class)*) ../../src/devices/board/drivers/x86/x86.cc:77 <platform-bus-x86.so>+0x2a33ad
  #17   0x000021afcf9e313e in fit::internal::target<(lambda at../../src/devices/board/drivers/x86/x86.cc:76:19), false, false, std::__2::allocator<std::byte>, void>::invoke(void*) ../../sdk/lib/fit/include/lib/fit/internal/function.h:183 <platform-bus-x86.so>+0x2a313e
  #18   0x000021afcfbab4c7 in fit::internal::function_base<16UL, false, void(), std::__2::allocator<std::byte>>::invoke(const fit::internal::function_base<16UL, false, void (), std::__2::allocator<std::byte> >*) ../../sdk/lib/fit/include/lib/fit/internal/function.h:522 <platform-bus-x86.so>+0x46b4c7
  #19   0x000021afcfbab342 in fit::function_impl<16UL, false, void(), std::__2::allocator<std::byte>>::operator()(const fit::function_impl<16UL, false, void (), std::__2::allocator<std::byte> >*) ../../sdk/lib/fit/include/lib/fit/function.h:315 <platform-bus-x86.so>+0x46b342
  #20   0x000021afcfcd98c3 in async::internal::retained_task::Handler(async_dispatcher_t*, async_task_t*, zx_status_t) ../../sdk/lib/async/task.cc:24 <platform-bus-x86.so>+0x5998c3
  #21   0x00002290f9924616 in λ(const driver_runtime::Dispatcher::post_task::(anon class)*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, zx_status_t) ../../src/devices/bin/driver_runtime/dispatcher.cc:789 <libdriver_runtime.so>+0x10a616
  #22   0x00002290f9924323 in fit::internal::target<(lambda at../../src/devices/bin/driver_runtime/dispatcher.cc:788:7), true, false, std::__2::allocator<std::byte>, void, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request>>, int>::invoke(void*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int) ../../sdk/lib/fit/include/lib/fit/internal/function.h:128 <libdriver_runtime.so>+0x10a323
  #23   0x00002290f9904b76 in fit::internal::function_base<24UL, true, void(std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request>>, int), std::__2::allocator<std::byte>>::invoke(const fit::internal::function_base<24UL, true, void (std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int), std::__2::allocator<std::byte> >*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int) ../../sdk/lib/fit/include/lib/fit/internal/function.h:522 <libdriver_runtime.so>+0xeab76
  #24   0x00002290f9904831 in fit::callback_impl<24UL, true, void(std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request>>, int), std::__2::allocator<std::byte>>::operator()(fit::callback_impl<24UL, true, void (std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int), std::__2::allocator<std::byte> >*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int) ../../sdk/lib/fit/include/lib/fit/function.h:471 <libdriver_runtime.so>+0xea831
  #25   0x00002290f98d5adc in driver_runtime::callback_request::Call(driver_runtime::callback_request*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, zx_status_t) ../../src/devices/bin/driver_runtime/callback_request.h:74 <libdriver_runtime.so>+0xbbadc
  #26   0x00002290f98e1e58 in driver_runtime::Dispatcher::dispatch_callback(driver_runtime::Dispatcher*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >) ../../src/devices/bin/driver_runtime/dispatcher.cc:1248 <libdriver_runtime.so>+0xc7e58
  #27   0x00002290f98e4159 in driver_runtime::Dispatcher::dispatch_callbacks(driver_runtime::Dispatcher*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../src/devices/bin/driver_runtime/dispatcher.cc:1308 <libdriver_runtime.so>+0xca159
  #28   0x00002290f9918414 in λ(const driver_runtime::Dispatcher::create_with_adder::(anon class)*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../src/devices/bin/driver_runtime/dispatcher.cc:353 <libdriver_runtime.so>+0xfe414
  #29   0x00002290f991812d in fit::internal::target<(lambda at../../src/devices/bin/driver_runtime/dispatcher.cc:351:7), true, false, std::__2::allocator<std::byte>, void, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter>>, fbl::ref_ptr<driver_runtime::Dispatcher>>::invoke(void*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../sdk/lib/fit/include/lib/fit/internal/function.h:128 <libdriver_runtime.so>+0xfe12d
  #30   0x00002290f9906fc7 in fit::internal::function_base<8UL, true, void(std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter>>, fbl::ref_ptr<driver_runtime::Dispatcher>), std::__2::allocator<std::byte>>::invoke(const fit::internal::function_base<8UL, true, void (std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>), std::__2::allocator<std::byte> >*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../sdk/lib/fit/include/lib/fit/internal/function.h:522 <libdriver_runtime.so>+0xecfc7
  #31   0x00002290f9906c66 in fit::function_impl<8UL, true, void(std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter>>, fbl::ref_ptr<driver_runtime::Dispatcher>), std::__2::allocator<std::byte>>::operator()(const fit::function_impl<8UL, true, void (std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>), std::__2::allocator<std::byte> >*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../sdk/lib/fit/include/lib/fit/function.h:315 <libdriver_runtime.so>+0xecc66
  #32   0x00002290f98e73d9 in driver_runtime::Dispatcher::event_waiter::invoke_callback(driver_runtime::Dispatcher::event_waiter*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../src/devices/bin/driver_runtime/dispatcher.h:543 <libdriver_runtime.so>+0xcd3d9
  #33   0x00002290f98e700d in driver_runtime::Dispatcher::event_waiter::handle_event(std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, async_dispatcher_t*, async::wait_base*, zx_status_t, zx_packet_signal_t const*) ../../src/devices/bin/driver_runtime/dispatcher.cc:1442 <libdriver_runtime.so>+0xcd00d
  #34   0x00002290f9918983 in async_loop_owned_event_handler<driver_runtime::Dispatcher::event_waiter>::handle_event(async_loop_owned_event_handler<driver_runtime::Dispatcher::event_waiter>*, async_dispatcher_t*, async::wait_base*, zx_status_t, zx_packet_signal_t const*) ../../src/devices/bin/driver_runtime/async_loop_owned_event_handler.h:59 <libdriver_runtime.so>+0xfe983
  #35   0x00002290f9918b9e in async::wait_method<async_loop_owned_event_handler<driver_runtime::Dispatcher::event_waiter>, &async_loop_owned_event_handler<driver_runtime::Dispatcher::event_waiter>::handle_event>::call_handler(async_dispatcher_t*, async_wait_t*, zx_status_t, zx_packet_signal_t const*) ../../sdk/lib/async/include/lib/async/cpp/wait.h:201 <libdriver_runtime.so>+0xfeb9e
  #36   0x00002290f99bf509 in async_loop_dispatch_wait(async_loop_t*, async_wait_t*, zx_status_t, zx_packet_signal_t const*) ../../sdk/lib/async-loop/loop.c:394 <libdriver_runtime.so>+0x1a5509
  #37   0x00002290f99b9958 in async_loop_run_once(async_loop_t*, zx_time_t) ../../sdk/lib/async-loop/loop.c:343 <libdriver_runtime.so>+0x19f958
  #38   0x00002290f99b9247 in async_loop_run(async_loop_t*, zx_time_t, _Bool) ../../sdk/lib/async-loop/loop.c:301 <libdriver_runtime.so>+0x19f247
  #39   0x00002290f99ba962 in async_loop_run_thread(void*) ../../sdk/lib/async-loop/loop.c:860 <libdriver_runtime.so>+0x1a0962
  #40   0x000041afd176ef30 in start_c11(void*) ../../zircon/third_party/ulib/musl/pthread/pthread_create.c:63 <libc.so>+0x84f30
  #41   0x000041afd18a448d in thread_trampoline(uintptr_t, uintptr_t) ../../zircon/system/ulib/runtime/thread.cc:100 <libc.so>+0x1ba48d

Link: acpica/acpica@1c28da22
Signed-off-by: Rafael J. Wysocki <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Tamir Duberstein <[email protected]>
[ rjw: Pick up the tag from Tamir ]
Signed-off-by: Rafael J. Wysocki <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jul 11, 2025
[ Upstream commit 6c7ffc9 ]

Remove redundant netif_napi_del() call from disconnect path.

A WARN may be triggered in __netif_napi_del_locked() during USB device
disconnect:

  WARNING: CPU: 0 PID: 11 at net/core/dev.c:7417 __netif_napi_del_locked+0x2b4/0x350

This happens because netif_napi_del() is called in the disconnect path while
NAPI is still enabled. However, it is not necessary to call netif_napi_del()
explicitly, since unregister_netdev() will handle NAPI teardown automatically
and safely. Removing the redundant call avoids triggering the warning.

Full trace:
 lan78xx 1-1:1.0 enu1: Failed to read register index 0x000000c4. ret = -ENODEV
 lan78xx 1-1:1.0 enu1: Failed to set MAC down with error -ENODEV
 lan78xx 1-1:1.0 enu1: Link is Down
 lan78xx 1-1:1.0 enu1: Failed to read register index 0x00000120. ret = -ENODEV
 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 11 at net/core/dev.c:7417 __netif_napi_del_locked+0x2b4/0x350
 Modules linked in: flexcan can_dev fuse
 CPU: 0 UID: 0 PID: 11 Comm: kworker/0:1 Not tainted 6.16.0-rc2-00624-ge926949dab03 #9 PREEMPT
 Hardware name: SKOV IMX8MP CPU revC - bd500 (DT)
 Workqueue: usb_hub_wq hub_event
 pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
 pc : __netif_napi_del_locked+0x2b4/0x350
 lr : __netif_napi_del_locked+0x7c/0x350
 sp : ffffffc085b673c0
 x29: ffffffc085b673c0 x28: ffffff800b7f2000 x27: ffffff800b7f20d8
 x26: ffffff80110bcf58 x25: ffffff80110bd978 x24: 1ffffff0022179eb
 x23: ffffff80110bc000 x22: ffffff800b7f5000 x21: ffffff80110bc000
 x20: ffffff80110bcf38 x19: ffffff80110bcf28 x18: dfffffc000000000
 x17: ffffffc081578940 x16: ffffffc08284cee0 x15: 0000000000000028
 x14: 0000000000000006 x13: 0000000000040000 x12: ffffffb0022179e8
 x11: 1ffffff0022179e7 x10: ffffffb0022179e7 x9 : dfffffc000000000
 x8 : 0000004ffdde8619 x7 : ffffff80110bcf3f x6 : 0000000000000001
 x5 : ffffff80110bcf38 x4 : ffffff80110bcf38 x3 : 0000000000000000
 x2 : 0000000000000000 x1 : 1ffffff0022179e7 x0 : 0000000000000000
 Call trace:
  __netif_napi_del_locked+0x2b4/0x350 (P)
  lan78xx_disconnect+0xf4/0x360
  usb_unbind_interface+0x158/0x718
  device_remove+0x100/0x150
  device_release_driver_internal+0x308/0x478
  device_release_driver+0x1c/0x30
  bus_remove_device+0x1a8/0x368
  device_del+0x2e0/0x7b0
  usb_disable_device+0x244/0x540
  usb_disconnect+0x220/0x758
  hub_event+0x105c/0x35e0
  process_one_work+0x760/0x17b0
  worker_thread+0x768/0xce8
  kthread+0x3bc/0x690
  ret_from_fork+0x10/0x20
 irq event stamp: 211604
 hardirqs last  enabled at (211603): [<ffffffc0828cc9ec>] _raw_spin_unlock_irqrestore+0x84/0x98
 hardirqs last disabled at (211604): [<ffffffc0828a9a84>] el1_dbg+0x24/0x80
 softirqs last  enabled at (211296): [<ffffffc080095f10>] handle_softirqs+0x820/0xbc8
 softirqs last disabled at (210993): [<ffffffc080010288>] __do_softirq+0x18/0x20
 ---[ end trace 0000000000000000 ]---
 lan78xx 1-1:1.0 enu1: failed to kill vid 0081/0

Fixes: ec4c7e1 ("lan78xx: Introduce NAPI polling support")
Suggested-by: Jakub Kicinski <[email protected]>
Signed-off-by: Oleksij Rempel <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jul 27, 2025
commit 9857af0 upstream.

Commit e77aff5 ("binderfs: fix use-after-free in binder_devices")
addressed a use-after-free where devices could be released without first
being removed from the binder_devices list. However, there is a similar
path in binder_free_proc() that was missed:

  ==================================================================
  BUG: KASAN: slab-use-after-free in binder_remove_device+0xd4/0x100
  Write of size 8 at addr ffff0000c773b900 by task umount/467
  CPU: 12 UID: 0 PID: 467 Comm: umount Not tainted 6.15.0-rc7-00138-g57483a362741 #9 PREEMPT
  Hardware name: linux,dummy-virt (DT)
  Call trace:
   binder_remove_device+0xd4/0x100
   binderfs_evict_inode+0x230/0x2f0
   evict+0x25c/0x5dc
   iput+0x304/0x480
   dentry_unlink_inode+0x208/0x46c
   __dentry_kill+0x154/0x530
   [...]

  Allocated by task 463:
   __kmalloc_cache_noprof+0x13c/0x324
   binderfs_binder_device_create.isra.0+0x138/0xa60
   binder_ctl_ioctl+0x1ac/0x230
  [...]

  Freed by task 215:
   kfree+0x184/0x31c
   binder_proc_dec_tmpref+0x33c/0x4ac
   binder_deferred_func+0xc10/0x1108
   process_one_work+0x520/0xba4
  [...]
  ==================================================================

Call binder_remove_device() within binder_free_proc() to ensure the
device is removed from the binder_devices list before being kfreed.

Cc: [email protected]
Fixes: 12d909c ("binderfs: add new binder devices to binder_devices")
Reported-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=4af454407ec393de51d6
Tested-by: [email protected]
Signed-off-by: Carlos Llamas <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
anthraxx pushed a commit that referenced this pull request Jul 27, 2025
[ Upstream commit ee684de ]

As shown in [1], it is possible to corrupt a BPF ELF file such that
arbitrary BPF instructions are loaded by libbpf. This can be done by
setting a symbol (BPF program) section offset to a large (unsigned)
number such that <section start + symbol offset> overflows and points
before the section data in the memory.

Consider the situation below where:
- prog_start = sec_start + symbol_offset    <-- size_t overflow here
- prog_end   = prog_start + prog_size

    prog_start        sec_start        prog_end        sec_end
        |                |                 |              |
        v                v                 v              v
    .....................|################################|............

The report in [1] also provides a corrupted BPF ELF which can be used as
a reproducer:

    $ readelf -S crash
    Section Headers:
      [Nr] Name              Type             Address           Offset
           Size              EntSize          Flags  Link  Info  Align
    ...
      [ 2] uretprobe.mu[...] PROGBITS         0000000000000000  00000040
           0000000000000068  0000000000000000  AX       0     0     8

    $ readelf -s crash
    Symbol table '.symtab' contains 8 entries:
       Num:    Value          Size Type    Bind   Vis      Ndx Name
    ...
         6: ffffffffffffffb8   104 FUNC    GLOBAL DEFAULT    2 handle_tp

Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will
point before the actual memory where section 2 is allocated.

This is also reported by AddressSanitizer:

    =================================================================
    ==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490
    READ of size 104 at 0x7c7302fe0000 thread T0
        #0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76)
        #1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856
        #2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928
        #3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930
        #4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067
        #5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090
        #6 0x000000400c16 in main /poc/poc.c:8
        #7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4)
        #8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667)
        #9 0x000000400b34 in _start (/poc/poc+0x400b34)

    0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8)
    allocated by thread T0 here:
        #0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b)
        #1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600)
        #2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018)
        #3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740

The problem here is that currently, libbpf only checks that the program
end is within the section bounds. There used to be a check
`while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was
removed by commit 6245947 ("libbpf: Allow gaps in BPF program
sections to support overriden weak functions").

Add a check for detecting the overflow of `sec_off + prog_sz` to
bpf_object__init_prog to fix this issue.

[1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md

Fixes: 6245947 ("libbpf: Allow gaps in BPF program sections to support overriden weak functions")
Reported-by: lmarch2 <[email protected]>
Signed-off-by: Viktor Malik <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Reviewed-by: Shung-Hsi Yu <[email protected]>
Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md
Link: https://lore.kernel.org/bpf/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jul 27, 2025
[ Upstream commit eedf3e3 ]

ACPICA commit 1c28da2242783579d59767617121035dafba18c3

This was originally done in NetBSD:
NetBSD/src@b69d1ac
and is the correct alternative to the smattering of `memcpy`s I
previously contributed to this repository.

This also sidesteps the newly strict checks added in UBSAN:
llvm/llvm-project@7926744

Before this change we see the following UBSAN stack trace in Fuchsia:

  #0    0x000021afcfdeca5e in acpi_rs_get_address_common(struct acpi_resource*, union aml_resource*) ../../third_party/acpica/source/components/resources/rsaddr.c:329 <platform-bus-x86.so>+0x6aca5e
  #1.2  0x000021982bc4af3c in ubsan_get_stack_trace() compiler-rt/lib/ubsan/ubsan_diag.cpp:41 <libclang_rt.asan.so>+0x41f3c
  #1.1  0x000021982bc4af3c in maybe_print_stack_trace() compiler-rt/lib/ubsan/ubsan_diag.cpp:51 <libclang_rt.asan.so>+0x41f3c
  #1    0x000021982bc4af3c in ~scoped_report() compiler-rt/lib/ubsan/ubsan_diag.cpp:395 <libclang_rt.asan.so>+0x41f3c
  #2    0x000021982bc4bb6f in handletype_mismatch_impl() compiler-rt/lib/ubsan/ubsan_handlers.cpp:137 <libclang_rt.asan.so>+0x42b6f
  #3    0x000021982bc4b723 in __ubsan_handle_type_mismatch_v1 compiler-rt/lib/ubsan/ubsan_handlers.cpp:142 <libclang_rt.asan.so>+0x42723
  #4    0x000021afcfdeca5e in acpi_rs_get_address_common(struct acpi_resource*, union aml_resource*) ../../third_party/acpica/source/components/resources/rsaddr.c:329 <platform-bus-x86.so>+0x6aca5e
  #5    0x000021afcfdf2089 in acpi_rs_convert_aml_to_resource(struct acpi_resource*, union aml_resource*, struct acpi_rsconvert_info*) ../../third_party/acpica/source/components/resources/rsmisc.c:355 <platform-bus-x86.so>+0x6b2089
  #6    0x000021afcfded169 in acpi_rs_convert_aml_to_resources(u8*, u32, u32, u8, void**) ../../third_party/acpica/source/components/resources/rslist.c:137 <platform-bus-x86.so>+0x6ad169
  #7    0x000021afcfe2d24a in acpi_ut_walk_aml_resources(struct acpi_walk_state*, u8*, acpi_size, acpi_walk_aml_callback, void**) ../../third_party/acpica/source/components/utilities/utresrc.c:237 <platform-bus-x86.so>+0x6ed24a
  #8    0x000021afcfde66b7 in acpi_rs_create_resource_list(union acpi_operand_object*, struct acpi_buffer*) ../../third_party/acpica/source/components/resources/rscreate.c:199 <platform-bus-x86.so>+0x6a66b7
  #9    0x000021afcfdf6979 in acpi_rs_get_method_data(acpi_handle, const char*, struct acpi_buffer*) ../../third_party/acpica/source/components/resources/rsutils.c:770 <platform-bus-x86.so>+0x6b6979
  #10   0x000021afcfdf708f in acpi_walk_resources(acpi_handle, char*, acpi_walk_resource_callback, void*) ../../third_party/acpica/source/components/resources/rsxface.c:731 <platform-bus-x86.so>+0x6b708f
  #11   0x000021afcfa95dcf in acpi::acpi_impl::walk_resources(acpi::acpi_impl*, acpi_handle, const char*, acpi::Acpi::resources_callable) ../../src/devices/board/lib/acpi/acpi-impl.cc:41 <platform-bus-x86.so>+0x355dcf
  #12   0x000021afcfaa8278 in acpi::device_builder::gather_resources(acpi::device_builder*, acpi::Acpi*, fidl::any_arena&, acpi::Manager*, acpi::device_builder::gather_resources_callback) ../../src/devices/board/lib/acpi/device-builder.cc:84 <platform-bus-x86.so>+0x368278
  #13   0x000021afcfbddb87 in acpi::Manager::configure_discovered_devices(acpi::Manager*) ../../src/devices/board/lib/acpi/manager.cc:75 <platform-bus-x86.so>+0x49db87
  #14   0x000021afcf99091d in publish_acpi_devices(acpi::Manager*, zx_device_t*, zx_device_t*) ../../src/devices/board/drivers/x86/acpi-nswalk.cc:95 <platform-bus-x86.so>+0x25091d
  #15   0x000021afcf9c1d4e in x86::X86::do_init(x86::X86*) ../../src/devices/board/drivers/x86/x86.cc:60 <platform-bus-x86.so>+0x281d4e
  #16   0x000021afcf9e33ad in λ(x86::X86::ddk_init::(anon class)*) ../../src/devices/board/drivers/x86/x86.cc:77 <platform-bus-x86.so>+0x2a33ad
  #17   0x000021afcf9e313e in fit::internal::target<(lambda at../../src/devices/board/drivers/x86/x86.cc:76:19), false, false, std::__2::allocator<std::byte>, void>::invoke(void*) ../../sdk/lib/fit/include/lib/fit/internal/function.h:183 <platform-bus-x86.so>+0x2a313e
  #18   0x000021afcfbab4c7 in fit::internal::function_base<16UL, false, void(), std::__2::allocator<std::byte>>::invoke(const fit::internal::function_base<16UL, false, void (), std::__2::allocator<std::byte> >*) ../../sdk/lib/fit/include/lib/fit/internal/function.h:522 <platform-bus-x86.so>+0x46b4c7
  #19   0x000021afcfbab342 in fit::function_impl<16UL, false, void(), std::__2::allocator<std::byte>>::operator()(const fit::function_impl<16UL, false, void (), std::__2::allocator<std::byte> >*) ../../sdk/lib/fit/include/lib/fit/function.h:315 <platform-bus-x86.so>+0x46b342
  #20   0x000021afcfcd98c3 in async::internal::retained_task::Handler(async_dispatcher_t*, async_task_t*, zx_status_t) ../../sdk/lib/async/task.cc:24 <platform-bus-x86.so>+0x5998c3
  #21   0x00002290f9924616 in λ(const driver_runtime::Dispatcher::post_task::(anon class)*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, zx_status_t) ../../src/devices/bin/driver_runtime/dispatcher.cc:789 <libdriver_runtime.so>+0x10a616
  #22   0x00002290f9924323 in fit::internal::target<(lambda at../../src/devices/bin/driver_runtime/dispatcher.cc:788:7), true, false, std::__2::allocator<std::byte>, void, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request>>, int>::invoke(void*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int) ../../sdk/lib/fit/include/lib/fit/internal/function.h:128 <libdriver_runtime.so>+0x10a323
  #23   0x00002290f9904b76 in fit::internal::function_base<24UL, true, void(std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request>>, int), std::__2::allocator<std::byte>>::invoke(const fit::internal::function_base<24UL, true, void (std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int), std::__2::allocator<std::byte> >*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int) ../../sdk/lib/fit/include/lib/fit/internal/function.h:522 <libdriver_runtime.so>+0xeab76
  #24   0x00002290f9904831 in fit::callback_impl<24UL, true, void(std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request>>, int), std::__2::allocator<std::byte>>::operator()(fit::callback_impl<24UL, true, void (std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int), std::__2::allocator<std::byte> >*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, int) ../../sdk/lib/fit/include/lib/fit/function.h:471 <libdriver_runtime.so>+0xea831
  #25   0x00002290f98d5adc in driver_runtime::callback_request::Call(driver_runtime::callback_request*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >, zx_status_t) ../../src/devices/bin/driver_runtime/callback_request.h:74 <libdriver_runtime.so>+0xbbadc
  #26   0x00002290f98e1e58 in driver_runtime::Dispatcher::dispatch_callback(driver_runtime::Dispatcher*, std::__2::unique_ptr<driver_runtime::callback_request, std::__2::default_delete<driver_runtime::callback_request> >) ../../src/devices/bin/driver_runtime/dispatcher.cc:1248 <libdriver_runtime.so>+0xc7e58
  #27   0x00002290f98e4159 in driver_runtime::Dispatcher::dispatch_callbacks(driver_runtime::Dispatcher*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../src/devices/bin/driver_runtime/dispatcher.cc:1308 <libdriver_runtime.so>+0xca159
  #28   0x00002290f9918414 in λ(const driver_runtime::Dispatcher::create_with_adder::(anon class)*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../src/devices/bin/driver_runtime/dispatcher.cc:353 <libdriver_runtime.so>+0xfe414
  #29   0x00002290f991812d in fit::internal::target<(lambda at../../src/devices/bin/driver_runtime/dispatcher.cc:351:7), true, false, std::__2::allocator<std::byte>, void, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter>>, fbl::ref_ptr<driver_runtime::Dispatcher>>::invoke(void*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../sdk/lib/fit/include/lib/fit/internal/function.h:128 <libdriver_runtime.so>+0xfe12d
  #30   0x00002290f9906fc7 in fit::internal::function_base<8UL, true, void(std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter>>, fbl::ref_ptr<driver_runtime::Dispatcher>), std::__2::allocator<std::byte>>::invoke(const fit::internal::function_base<8UL, true, void (std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>), std::__2::allocator<std::byte> >*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../sdk/lib/fit/include/lib/fit/internal/function.h:522 <libdriver_runtime.so>+0xecfc7
  #31   0x00002290f9906c66 in fit::function_impl<8UL, true, void(std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter>>, fbl::ref_ptr<driver_runtime::Dispatcher>), std::__2::allocator<std::byte>>::operator()(const fit::function_impl<8UL, true, void (std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>), std::__2::allocator<std::byte> >*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../sdk/lib/fit/include/lib/fit/function.h:315 <libdriver_runtime.so>+0xecc66
  #32   0x00002290f98e73d9 in driver_runtime::Dispatcher::event_waiter::invoke_callback(driver_runtime::Dispatcher::event_waiter*, std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, fbl::ref_ptr<driver_runtime::Dispatcher>) ../../src/devices/bin/driver_runtime/dispatcher.h:543 <libdriver_runtime.so>+0xcd3d9
  #33   0x00002290f98e700d in driver_runtime::Dispatcher::event_waiter::handle_event(std::__2::unique_ptr<driver_runtime::Dispatcher::event_waiter, std::__2::default_delete<driver_runtime::Dispatcher::event_waiter> >, async_dispatcher_t*, async::wait_base*, zx_status_t, zx_packet_signal_t const*) ../../src/devices/bin/driver_runtime/dispatcher.cc:1442 <libdriver_runtime.so>+0xcd00d
  #34   0x00002290f9918983 in async_loop_owned_event_handler<driver_runtime::Dispatcher::event_waiter>::handle_event(async_loop_owned_event_handler<driver_runtime::Dispatcher::event_waiter>*, async_dispatcher_t*, async::wait_base*, zx_status_t, zx_packet_signal_t const*) ../../src/devices/bin/driver_runtime/async_loop_owned_event_handler.h:59 <libdriver_runtime.so>+0xfe983
  #35   0x00002290f9918b9e in async::wait_method<async_loop_owned_event_handler<driver_runtime::Dispatcher::event_waiter>, &async_loop_owned_event_handler<driver_runtime::Dispatcher::event_waiter>::handle_event>::call_handler(async_dispatcher_t*, async_wait_t*, zx_status_t, zx_packet_signal_t const*) ../../sdk/lib/async/include/lib/async/cpp/wait.h:201 <libdriver_runtime.so>+0xfeb9e
  #36   0x00002290f99bf509 in async_loop_dispatch_wait(async_loop_t*, async_wait_t*, zx_status_t, zx_packet_signal_t const*) ../../sdk/lib/async-loop/loop.c:394 <libdriver_runtime.so>+0x1a5509
  #37   0x00002290f99b9958 in async_loop_run_once(async_loop_t*, zx_time_t) ../../sdk/lib/async-loop/loop.c:343 <libdriver_runtime.so>+0x19f958
  #38   0x00002290f99b9247 in async_loop_run(async_loop_t*, zx_time_t, _Bool) ../../sdk/lib/async-loop/loop.c:301 <libdriver_runtime.so>+0x19f247
  #39   0x00002290f99ba962 in async_loop_run_thread(void*) ../../sdk/lib/async-loop/loop.c:860 <libdriver_runtime.so>+0x1a0962
  #40   0x000041afd176ef30 in start_c11(void*) ../../zircon/third_party/ulib/musl/pthread/pthread_create.c:63 <libc.so>+0x84f30
  #41   0x000041afd18a448d in thread_trampoline(uintptr_t, uintptr_t) ../../zircon/system/ulib/runtime/thread.cc:100 <libc.so>+0x1ba48d

Link: acpica/acpica@1c28da22
Signed-off-by: Rafael J. Wysocki <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Tamir Duberstein <[email protected]>
[ rjw: Pick up the tag from Tamir ]
Signed-off-by: Rafael J. Wysocki <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jul 27, 2025
[ Upstream commit 6c7ffc9 ]

Remove redundant netif_napi_del() call from disconnect path.

A WARN may be triggered in __netif_napi_del_locked() during USB device
disconnect:

  WARNING: CPU: 0 PID: 11 at net/core/dev.c:7417 __netif_napi_del_locked+0x2b4/0x350

This happens because netif_napi_del() is called in the disconnect path while
NAPI is still enabled. However, it is not necessary to call netif_napi_del()
explicitly, since unregister_netdev() will handle NAPI teardown automatically
and safely. Removing the redundant call avoids triggering the warning.

Full trace:
 lan78xx 1-1:1.0 enu1: Failed to read register index 0x000000c4. ret = -ENODEV
 lan78xx 1-1:1.0 enu1: Failed to set MAC down with error -ENODEV
 lan78xx 1-1:1.0 enu1: Link is Down
 lan78xx 1-1:1.0 enu1: Failed to read register index 0x00000120. ret = -ENODEV
 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 11 at net/core/dev.c:7417 __netif_napi_del_locked+0x2b4/0x350
 Modules linked in: flexcan can_dev fuse
 CPU: 0 UID: 0 PID: 11 Comm: kworker/0:1 Not tainted 6.16.0-rc2-00624-ge926949dab03 #9 PREEMPT
 Hardware name: SKOV IMX8MP CPU revC - bd500 (DT)
 Workqueue: usb_hub_wq hub_event
 pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
 pc : __netif_napi_del_locked+0x2b4/0x350
 lr : __netif_napi_del_locked+0x7c/0x350
 sp : ffffffc085b673c0
 x29: ffffffc085b673c0 x28: ffffff800b7f2000 x27: ffffff800b7f20d8
 x26: ffffff80110bcf58 x25: ffffff80110bd978 x24: 1ffffff0022179eb
 x23: ffffff80110bc000 x22: ffffff800b7f5000 x21: ffffff80110bc000
 x20: ffffff80110bcf38 x19: ffffff80110bcf28 x18: dfffffc000000000
 x17: ffffffc081578940 x16: ffffffc08284cee0 x15: 0000000000000028
 x14: 0000000000000006 x13: 0000000000040000 x12: ffffffb0022179e8
 x11: 1ffffff0022179e7 x10: ffffffb0022179e7 x9 : dfffffc000000000
 x8 : 0000004ffdde8619 x7 : ffffff80110bcf3f x6 : 0000000000000001
 x5 : ffffff80110bcf38 x4 : ffffff80110bcf38 x3 : 0000000000000000
 x2 : 0000000000000000 x1 : 1ffffff0022179e7 x0 : 0000000000000000
 Call trace:
  __netif_napi_del_locked+0x2b4/0x350 (P)
  lan78xx_disconnect+0xf4/0x360
  usb_unbind_interface+0x158/0x718
  device_remove+0x100/0x150
  device_release_driver_internal+0x308/0x478
  device_release_driver+0x1c/0x30
  bus_remove_device+0x1a8/0x368
  device_del+0x2e0/0x7b0
  usb_disable_device+0x244/0x540
  usb_disconnect+0x220/0x758
  hub_event+0x105c/0x35e0
  process_one_work+0x760/0x17b0
  worker_thread+0x768/0xce8
  kthread+0x3bc/0x690
  ret_from_fork+0x10/0x20
 irq event stamp: 211604
 hardirqs last  enabled at (211603): [<ffffffc0828cc9ec>] _raw_spin_unlock_irqrestore+0x84/0x98
 hardirqs last disabled at (211604): [<ffffffc0828a9a84>] el1_dbg+0x24/0x80
 softirqs last  enabled at (211296): [<ffffffc080095f10>] handle_softirqs+0x820/0xbc8
 softirqs last disabled at (210993): [<ffffffc080010288>] __do_softirq+0x18/0x20
 ---[ end trace 0000000000000000 ]---
 lan78xx 1-1:1.0 enu1: failed to kill vid 0081/0

Fixes: ec4c7e1 ("lan78xx: Introduce NAPI polling support")
Suggested-by: Jakub Kicinski <[email protected]>
Signed-off-by: Oleksij Rempel <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jul 27, 2025
[ Upstream commit 2d72afb ]

A crash in conntrack was reported while trying to unlink the conntrack
entry from the hash bucket list:
    [exception RIP: __nf_ct_delete_from_lists+172]
    [..]
 #7 [ff539b5a2b043aa0] nf_ct_delete at ffffffffc124d421 [nf_conntrack]
 #8 [ff539b5a2b043ad0] nf_ct_gc_expired at ffffffffc124d999 [nf_conntrack]
 #9 [ff539b5a2b043ae0] __nf_conntrack_find_get at ffffffffc124efbc [nf_conntrack]
    [..]

The nf_conn struct is marked as allocated from slab but appears to be in
a partially initialised state:

 ct hlist pointer is garbage; looks like the ct hash value
 (hence crash).
 ct->status is equal to IPS_CONFIRMED|IPS_DYING, which is expected
 ct->timeout is 30000 (=30s), which is unexpected.

Everything else looks like normal udp conntrack entry.  If we ignore
ct->status and pretend its 0, the entry matches those that are newly
allocated but not yet inserted into the hash:
  - ct hlist pointers are overloaded and store/cache the raw tuple hash
  - ct->timeout matches the relative time expected for a new udp flow
    rather than the absolute 'jiffies' value.

If it were not for the presence of IPS_CONFIRMED,
__nf_conntrack_find_get() would have skipped the entry.

Theory is that we did hit following race:

cpu x 			cpu y			cpu z
 found entry E		found entry E
 E is expired		<preemption>
 nf_ct_delete()
 return E to rcu slab
					init_conntrack
					E is re-inited,
					ct->status set to 0
					reply tuplehash hnnode.pprev
					stores hash value.

cpu y found E right before it was deleted on cpu x.
E is now re-inited on cpu z.  cpu y was preempted before
checking for expiry and/or confirm bit.

					->refcnt set to 1
					E now owned by skb
					->timeout set to 30000

If cpu y were to resume now, it would observe E as
expired but would skip E due to missing CONFIRMED bit.

					nf_conntrack_confirm gets called
					sets: ct->status |= CONFIRMED
					This is wrong: E is not yet added
					to hashtable.

cpu y resumes, it observes E as expired but CONFIRMED:
			<resumes>
			nf_ct_expired()
			 -> yes (ct->timeout is 30s)
			confirmed bit set.

cpu y will try to delete E from the hashtable:
			nf_ct_delete() -> set DYING bit
			__nf_ct_delete_from_lists

Even this scenario doesn't guarantee a crash:
cpu z still holds the table bucket lock(s) so y blocks:

			wait for spinlock held by z

					CONFIRMED is set but there is no
					guarantee ct will be added to hash:
					"chaintoolong" or "clash resolution"
					logic both skip the insert step.
					reply hnnode.pprev still stores the
					hash value.

					unlocks spinlock
					return NF_DROP
			<unblocks, then
			 crashes on hlist_nulls_del_rcu pprev>

In case CPU z does insert the entry into the hashtable, cpu y will unlink
E again right away but no crash occurs.

Without 'cpu y' race, 'garbage' hlist is of no consequence:
ct refcnt remains at 1, eventually skb will be free'd and E gets
destroyed via: nf_conntrack_put -> nf_conntrack_destroy -> nf_ct_destroy.

To resolve this, move the IPS_CONFIRMED assignment after the table
insertion but before the unlock.

Pablo points out that the confirm-bit-store could be reordered to happen
before hlist add resp. the timeout fixup, so switch to set_bit and
before_atomic memory barrier to prevent this.

It doesn't matter if other CPUs can observe a newly inserted entry right
before the CONFIRMED bit was set:

Such event cannot be distinguished from above "E is the old incarnation"
case: the entry will be skipped.

Also change nf_ct_should_gc() to first check the confirmed bit.

The gc sequence is:
 1. Check if entry has expired, if not skip to next entry
 2. Obtain a reference to the expired entry.
 3. Call nf_ct_should_gc() to double-check step 1.

nf_ct_should_gc() is thus called only for entries that already failed an
expiry check. After this patch, once the confirmed bit check passes
ct->timeout has been altered to reflect the absolute 'best before' date
instead of a relative time.  Step 3 will therefore not remove the entry.

Without this change to nf_ct_should_gc() we could still get this sequence:

 1. Check if entry has expired.
 2. Obtain a reference.
 3. Call nf_ct_should_gc() to double-check step 1:
    4 - entry is still observed as expired
    5 - meanwhile, ct->timeout is corrected to absolute value on other CPU
      and confirm bit gets set
    6 - confirm bit is seen
    7 - valid entry is removed again

First do check 6), then 4) so the gc expiry check always picks up either
confirmed bit unset (entry gets skipped) or expiry re-check failure for
re-inited conntrack objects.

This change cannot be backported to releases before 5.19. Without
commit 8a75a2c ("netfilter: conntrack: remove unconfirmed list")
|= IPS_CONFIRMED line cannot be moved without further changes.

Cc: Razvan Cojocaru <[email protected]>
Link: https://lore.kernel.org/netfilter-devel/[email protected]/
Link: https://lore.kernel.org/netfilter-devel/[email protected]/
Fixes: 1397af5 ("netfilter: conntrack: remove the percpu dying list")
Signed-off-by: Florian Westphal <[email protected]>
Signed-off-by: Pablo Neira Ayuso <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jul 27, 2025
[ Upstream commit 2d72afb ]

A crash in conntrack was reported while trying to unlink the conntrack
entry from the hash bucket list:
    [exception RIP: __nf_ct_delete_from_lists+172]
    [..]
 #7 [ff539b5a2b043aa0] nf_ct_delete at ffffffffc124d421 [nf_conntrack]
 #8 [ff539b5a2b043ad0] nf_ct_gc_expired at ffffffffc124d999 [nf_conntrack]
 #9 [ff539b5a2b043ae0] __nf_conntrack_find_get at ffffffffc124efbc [nf_conntrack]
    [..]

The nf_conn struct is marked as allocated from slab but appears to be in
a partially initialised state:

 ct hlist pointer is garbage; looks like the ct hash value
 (hence crash).
 ct->status is equal to IPS_CONFIRMED|IPS_DYING, which is expected
 ct->timeout is 30000 (=30s), which is unexpected.

Everything else looks like normal udp conntrack entry.  If we ignore
ct->status and pretend its 0, the entry matches those that are newly
allocated but not yet inserted into the hash:
  - ct hlist pointers are overloaded and store/cache the raw tuple hash
  - ct->timeout matches the relative time expected for a new udp flow
    rather than the absolute 'jiffies' value.

If it were not for the presence of IPS_CONFIRMED,
__nf_conntrack_find_get() would have skipped the entry.

Theory is that we did hit following race:

cpu x 			cpu y			cpu z
 found entry E		found entry E
 E is expired		<preemption>
 nf_ct_delete()
 return E to rcu slab
					init_conntrack
					E is re-inited,
					ct->status set to 0
					reply tuplehash hnnode.pprev
					stores hash value.

cpu y found E right before it was deleted on cpu x.
E is now re-inited on cpu z.  cpu y was preempted before
checking for expiry and/or confirm bit.

					->refcnt set to 1
					E now owned by skb
					->timeout set to 30000

If cpu y were to resume now, it would observe E as
expired but would skip E due to missing CONFIRMED bit.

					nf_conntrack_confirm gets called
					sets: ct->status |= CONFIRMED
					This is wrong: E is not yet added
					to hashtable.

cpu y resumes, it observes E as expired but CONFIRMED:
			<resumes>
			nf_ct_expired()
			 -> yes (ct->timeout is 30s)
			confirmed bit set.

cpu y will try to delete E from the hashtable:
			nf_ct_delete() -> set DYING bit
			__nf_ct_delete_from_lists

Even this scenario doesn't guarantee a crash:
cpu z still holds the table bucket lock(s) so y blocks:

			wait for spinlock held by z

					CONFIRMED is set but there is no
					guarantee ct will be added to hash:
					"chaintoolong" or "clash resolution"
					logic both skip the insert step.
					reply hnnode.pprev still stores the
					hash value.

					unlocks spinlock
					return NF_DROP
			<unblocks, then
			 crashes on hlist_nulls_del_rcu pprev>

In case CPU z does insert the entry into the hashtable, cpu y will unlink
E again right away but no crash occurs.

Without 'cpu y' race, 'garbage' hlist is of no consequence:
ct refcnt remains at 1, eventually skb will be free'd and E gets
destroyed via: nf_conntrack_put -> nf_conntrack_destroy -> nf_ct_destroy.

To resolve this, move the IPS_CONFIRMED assignment after the table
insertion but before the unlock.

Pablo points out that the confirm-bit-store could be reordered to happen
before hlist add resp. the timeout fixup, so switch to set_bit and
before_atomic memory barrier to prevent this.

It doesn't matter if other CPUs can observe a newly inserted entry right
before the CONFIRMED bit was set:

Such event cannot be distinguished from above "E is the old incarnation"
case: the entry will be skipped.

Also change nf_ct_should_gc() to first check the confirmed bit.

The gc sequence is:
 1. Check if entry has expired, if not skip to next entry
 2. Obtain a reference to the expired entry.
 3. Call nf_ct_should_gc() to double-check step 1.

nf_ct_should_gc() is thus called only for entries that already failed an
expiry check. After this patch, once the confirmed bit check passes
ct->timeout has been altered to reflect the absolute 'best before' date
instead of a relative time.  Step 3 will therefore not remove the entry.

Without this change to nf_ct_should_gc() we could still get this sequence:

 1. Check if entry has expired.
 2. Obtain a reference.
 3. Call nf_ct_should_gc() to double-check step 1:
    4 - entry is still observed as expired
    5 - meanwhile, ct->timeout is corrected to absolute value on other CPU
      and confirm bit gets set
    6 - confirm bit is seen
    7 - valid entry is removed again

First do check 6), then 4) so the gc expiry check always picks up either
confirmed bit unset (entry gets skipped) or expiry re-check failure for
re-inited conntrack objects.

This change cannot be backported to releases before 5.19. Without
commit 8a75a2c ("netfilter: conntrack: remove unconfirmed list")
|= IPS_CONFIRMED line cannot be moved without further changes.

Cc: Razvan Cojocaru <[email protected]>
Link: https://lore.kernel.org/netfilter-devel/[email protected]/
Link: https://lore.kernel.org/netfilter-devel/[email protected]/
Fixes: 1397af5 ("netfilter: conntrack: remove the percpu dying list")
Signed-off-by: Florian Westphal <[email protected]>
Signed-off-by: Pablo Neira Ayuso <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jul 27, 2025
[ Upstream commit 2d72afb ]

A crash in conntrack was reported while trying to unlink the conntrack
entry from the hash bucket list:
    [exception RIP: __nf_ct_delete_from_lists+172]
    [..]
 #7 [ff539b5a2b043aa0] nf_ct_delete at ffffffffc124d421 [nf_conntrack]
 #8 [ff539b5a2b043ad0] nf_ct_gc_expired at ffffffffc124d999 [nf_conntrack]
 #9 [ff539b5a2b043ae0] __nf_conntrack_find_get at ffffffffc124efbc [nf_conntrack]
    [..]

The nf_conn struct is marked as allocated from slab but appears to be in
a partially initialised state:

 ct hlist pointer is garbage; looks like the ct hash value
 (hence crash).
 ct->status is equal to IPS_CONFIRMED|IPS_DYING, which is expected
 ct->timeout is 30000 (=30s), which is unexpected.

Everything else looks like normal udp conntrack entry.  If we ignore
ct->status and pretend its 0, the entry matches those that are newly
allocated but not yet inserted into the hash:
  - ct hlist pointers are overloaded and store/cache the raw tuple hash
  - ct->timeout matches the relative time expected for a new udp flow
    rather than the absolute 'jiffies' value.

If it were not for the presence of IPS_CONFIRMED,
__nf_conntrack_find_get() would have skipped the entry.

Theory is that we did hit following race:

cpu x 			cpu y			cpu z
 found entry E		found entry E
 E is expired		<preemption>
 nf_ct_delete()
 return E to rcu slab
					init_conntrack
					E is re-inited,
					ct->status set to 0
					reply tuplehash hnnode.pprev
					stores hash value.

cpu y found E right before it was deleted on cpu x.
E is now re-inited on cpu z.  cpu y was preempted before
checking for expiry and/or confirm bit.

					->refcnt set to 1
					E now owned by skb
					->timeout set to 30000

If cpu y were to resume now, it would observe E as
expired but would skip E due to missing CONFIRMED bit.

					nf_conntrack_confirm gets called
					sets: ct->status |= CONFIRMED
					This is wrong: E is not yet added
					to hashtable.

cpu y resumes, it observes E as expired but CONFIRMED:
			<resumes>
			nf_ct_expired()
			 -> yes (ct->timeout is 30s)
			confirmed bit set.

cpu y will try to delete E from the hashtable:
			nf_ct_delete() -> set DYING bit
			__nf_ct_delete_from_lists

Even this scenario doesn't guarantee a crash:
cpu z still holds the table bucket lock(s) so y blocks:

			wait for spinlock held by z

					CONFIRMED is set but there is no
					guarantee ct will be added to hash:
					"chaintoolong" or "clash resolution"
					logic both skip the insert step.
					reply hnnode.pprev still stores the
					hash value.

					unlocks spinlock
					return NF_DROP
			<unblocks, then
			 crashes on hlist_nulls_del_rcu pprev>

In case CPU z does insert the entry into the hashtable, cpu y will unlink
E again right away but no crash occurs.

Without 'cpu y' race, 'garbage' hlist is of no consequence:
ct refcnt remains at 1, eventually skb will be free'd and E gets
destroyed via: nf_conntrack_put -> nf_conntrack_destroy -> nf_ct_destroy.

To resolve this, move the IPS_CONFIRMED assignment after the table
insertion but before the unlock.

Pablo points out that the confirm-bit-store could be reordered to happen
before hlist add resp. the timeout fixup, so switch to set_bit and
before_atomic memory barrier to prevent this.

It doesn't matter if other CPUs can observe a newly inserted entry right
before the CONFIRMED bit was set:

Such event cannot be distinguished from above "E is the old incarnation"
case: the entry will be skipped.

Also change nf_ct_should_gc() to first check the confirmed bit.

The gc sequence is:
 1. Check if entry has expired, if not skip to next entry
 2. Obtain a reference to the expired entry.
 3. Call nf_ct_should_gc() to double-check step 1.

nf_ct_should_gc() is thus called only for entries that already failed an
expiry check. After this patch, once the confirmed bit check passes
ct->timeout has been altered to reflect the absolute 'best before' date
instead of a relative time.  Step 3 will therefore not remove the entry.

Without this change to nf_ct_should_gc() we could still get this sequence:

 1. Check if entry has expired.
 2. Obtain a reference.
 3. Call nf_ct_should_gc() to double-check step 1:
    4 - entry is still observed as expired
    5 - meanwhile, ct->timeout is corrected to absolute value on other CPU
      and confirm bit gets set
    6 - confirm bit is seen
    7 - valid entry is removed again

First do check 6), then 4) so the gc expiry check always picks up either
confirmed bit unset (entry gets skipped) or expiry re-check failure for
re-inited conntrack objects.

This change cannot be backported to releases before 5.19. Without
commit 8a75a2c ("netfilter: conntrack: remove unconfirmed list")
|= IPS_CONFIRMED line cannot be moved without further changes.

Cc: Razvan Cojocaru <[email protected]>
Link: https://lore.kernel.org/netfilter-devel/[email protected]/
Link: https://lore.kernel.org/netfilter-devel/[email protected]/
Fixes: 1397af5 ("netfilter: conntrack: remove the percpu dying list")
Signed-off-by: Florian Westphal <[email protected]>
Signed-off-by: Pablo Neira Ayuso <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Jul 28, 2025
[ Upstream commit 2d72afb ]

A crash in conntrack was reported while trying to unlink the conntrack
entry from the hash bucket list:
    [exception RIP: __nf_ct_delete_from_lists+172]
    [..]
 #7 [ff539b5a2b043aa0] nf_ct_delete at ffffffffc124d421 [nf_conntrack]
 #8 [ff539b5a2b043ad0] nf_ct_gc_expired at ffffffffc124d999 [nf_conntrack]
 #9 [ff539b5a2b043ae0] __nf_conntrack_find_get at ffffffffc124efbc [nf_conntrack]
    [..]

The nf_conn struct is marked as allocated from slab but appears to be in
a partially initialised state:

 ct hlist pointer is garbage; looks like the ct hash value
 (hence crash).
 ct->status is equal to IPS_CONFIRMED|IPS_DYING, which is expected
 ct->timeout is 30000 (=30s), which is unexpected.

Everything else looks like normal udp conntrack entry.  If we ignore
ct->status and pretend its 0, the entry matches those that are newly
allocated but not yet inserted into the hash:
  - ct hlist pointers are overloaded and store/cache the raw tuple hash
  - ct->timeout matches the relative time expected for a new udp flow
    rather than the absolute 'jiffies' value.

If it were not for the presence of IPS_CONFIRMED,
__nf_conntrack_find_get() would have skipped the entry.

Theory is that we did hit following race:

cpu x 			cpu y			cpu z
 found entry E		found entry E
 E is expired		<preemption>
 nf_ct_delete()
 return E to rcu slab
					init_conntrack
					E is re-inited,
					ct->status set to 0
					reply tuplehash hnnode.pprev
					stores hash value.

cpu y found E right before it was deleted on cpu x.
E is now re-inited on cpu z.  cpu y was preempted before
checking for expiry and/or confirm bit.

					->refcnt set to 1
					E now owned by skb
					->timeout set to 30000

If cpu y were to resume now, it would observe E as
expired but would skip E due to missing CONFIRMED bit.

					nf_conntrack_confirm gets called
					sets: ct->status |= CONFIRMED
					This is wrong: E is not yet added
					to hashtable.

cpu y resumes, it observes E as expired but CONFIRMED:
			<resumes>
			nf_ct_expired()
			 -> yes (ct->timeout is 30s)
			confirmed bit set.

cpu y will try to delete E from the hashtable:
			nf_ct_delete() -> set DYING bit
			__nf_ct_delete_from_lists

Even this scenario doesn't guarantee a crash:
cpu z still holds the table bucket lock(s) so y blocks:

			wait for spinlock held by z

					CONFIRMED is set but there is no
					guarantee ct will be added to hash:
					"chaintoolong" or "clash resolution"
					logic both skip the insert step.
					reply hnnode.pprev still stores the
					hash value.

					unlocks spinlock
					return NF_DROP
			<unblocks, then
			 crashes on hlist_nulls_del_rcu pprev>

In case CPU z does insert the entry into the hashtable, cpu y will unlink
E again right away but no crash occurs.

Without 'cpu y' race, 'garbage' hlist is of no consequence:
ct refcnt remains at 1, eventually skb will be free'd and E gets
destroyed via: nf_conntrack_put -> nf_conntrack_destroy -> nf_ct_destroy.

To resolve this, move the IPS_CONFIRMED assignment after the table
insertion but before the unlock.

Pablo points out that the confirm-bit-store could be reordered to happen
before hlist add resp. the timeout fixup, so switch to set_bit and
before_atomic memory barrier to prevent this.

It doesn't matter if other CPUs can observe a newly inserted entry right
before the CONFIRMED bit was set:

Such event cannot be distinguished from above "E is the old incarnation"
case: the entry will be skipped.

Also change nf_ct_should_gc() to first check the confirmed bit.

The gc sequence is:
 1. Check if entry has expired, if not skip to next entry
 2. Obtain a reference to the expired entry.
 3. Call nf_ct_should_gc() to double-check step 1.

nf_ct_should_gc() is thus called only for entries that already failed an
expiry check. After this patch, once the confirmed bit check passes
ct->timeout has been altered to reflect the absolute 'best before' date
instead of a relative time.  Step 3 will therefore not remove the entry.

Without this change to nf_ct_should_gc() we could still get this sequence:

 1. Check if entry has expired.
 2. Obtain a reference.
 3. Call nf_ct_should_gc() to double-check step 1:
    4 - entry is still observed as expired
    5 - meanwhile, ct->timeout is corrected to absolute value on other CPU
      and confirm bit gets set
    6 - confirm bit is seen
    7 - valid entry is removed again

First do check 6), then 4) so the gc expiry check always picks up either
confirmed bit unset (entry gets skipped) or expiry re-check failure for
re-inited conntrack objects.

This change cannot be backported to releases before 5.19. Without
commit 8a75a2c ("netfilter: conntrack: remove unconfirmed list")
|= IPS_CONFIRMED line cannot be moved without further changes.

Cc: Razvan Cojocaru <[email protected]>
Link: https://lore.kernel.org/netfilter-devel/[email protected]/
Link: https://lore.kernel.org/netfilter-devel/[email protected]/
Fixes: 1397af5 ("netfilter: conntrack: remove the percpu dying list")
Signed-off-by: Florian Westphal <[email protected]>
Signed-off-by: Pablo Neira Ayuso <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Aug 1, 2025
A crash in conntrack was reported while trying to unlink the conntrack
entry from the hash bucket list:
    [exception RIP: __nf_ct_delete_from_lists+172]
    [..]
 #7 [ff539b5a2b043aa0] nf_ct_delete at ffffffffc124d421 [nf_conntrack]
 #8 [ff539b5a2b043ad0] nf_ct_gc_expired at ffffffffc124d999 [nf_conntrack]
 #9 [ff539b5a2b043ae0] __nf_conntrack_find_get at ffffffffc124efbc [nf_conntrack]
    [..]

The nf_conn struct is marked as allocated from slab but appears to be in
a partially initialised state:

 ct hlist pointer is garbage; looks like the ct hash value
 (hence crash).
 ct->status is equal to IPS_CONFIRMED|IPS_DYING, which is expected
 ct->timeout is 30000 (=30s), which is unexpected.

Everything else looks like normal udp conntrack entry.  If we ignore
ct->status and pretend its 0, the entry matches those that are newly
allocated but not yet inserted into the hash:
  - ct hlist pointers are overloaded and store/cache the raw tuple hash
  - ct->timeout matches the relative time expected for a new udp flow
    rather than the absolute 'jiffies' value.

If it were not for the presence of IPS_CONFIRMED,
__nf_conntrack_find_get() would have skipped the entry.

Theory is that we did hit following race:

cpu x 			cpu y			cpu z
 found entry E		found entry E
 E is expired		<preemption>
 nf_ct_delete()
 return E to rcu slab
					init_conntrack
					E is re-inited,
					ct->status set to 0
					reply tuplehash hnnode.pprev
					stores hash value.

cpu y found E right before it was deleted on cpu x.
E is now re-inited on cpu z.  cpu y was preempted before
checking for expiry and/or confirm bit.

					->refcnt set to 1
					E now owned by skb
					->timeout set to 30000

If cpu y were to resume now, it would observe E as
expired but would skip E due to missing CONFIRMED bit.

					nf_conntrack_confirm gets called
					sets: ct->status |= CONFIRMED
					This is wrong: E is not yet added
					to hashtable.

cpu y resumes, it observes E as expired but CONFIRMED:
			<resumes>
			nf_ct_expired()
			 -> yes (ct->timeout is 30s)
			confirmed bit set.

cpu y will try to delete E from the hashtable:
			nf_ct_delete() -> set DYING bit
			__nf_ct_delete_from_lists

Even this scenario doesn't guarantee a crash:
cpu z still holds the table bucket lock(s) so y blocks:

			wait for spinlock held by z

					CONFIRMED is set but there is no
					guarantee ct will be added to hash:
					"chaintoolong" or "clash resolution"
					logic both skip the insert step.
					reply hnnode.pprev still stores the
					hash value.

					unlocks spinlock
					return NF_DROP
			<unblocks, then
			 crashes on hlist_nulls_del_rcu pprev>

In case CPU z does insert the entry into the hashtable, cpu y will unlink
E again right away but no crash occurs.

Without 'cpu y' race, 'garbage' hlist is of no consequence:
ct refcnt remains at 1, eventually skb will be free'd and E gets
destroyed via: nf_conntrack_put -> nf_conntrack_destroy -> nf_ct_destroy.

To resolve this, move the IPS_CONFIRMED assignment after the table
insertion but before the unlock.

Pablo points out that the confirm-bit-store could be reordered to happen
before hlist add resp. the timeout fixup, so switch to set_bit and
before_atomic memory barrier to prevent this.

It doesn't matter if other CPUs can observe a newly inserted entry right
before the CONFIRMED bit was set:

Such event cannot be distinguished from above "E is the old incarnation"
case: the entry will be skipped.

Also change nf_ct_should_gc() to first check the confirmed bit.

The gc sequence is:
 1. Check if entry has expired, if not skip to next entry
 2. Obtain a reference to the expired entry.
 3. Call nf_ct_should_gc() to double-check step 1.

nf_ct_should_gc() is thus called only for entries that already failed an
expiry check. After this patch, once the confirmed bit check passes
ct->timeout has been altered to reflect the absolute 'best before' date
instead of a relative time.  Step 3 will therefore not remove the entry.

Without this change to nf_ct_should_gc() we could still get this sequence:

 1. Check if entry has expired.
 2. Obtain a reference.
 3. Call nf_ct_should_gc() to double-check step 1:
    4 - entry is still observed as expired
    5 - meanwhile, ct->timeout is corrected to absolute value on other CPU
      and confirm bit gets set
    6 - confirm bit is seen
    7 - valid entry is removed again

First do check 6), then 4) so the gc expiry check always picks up either
confirmed bit unset (entry gets skipped) or expiry re-check failure for
re-inited conntrack objects.

This change cannot be backported to releases before 5.19. Without
commit 8a75a2c ("netfilter: conntrack: remove unconfirmed list")
|= IPS_CONFIRMED line cannot be moved without further changes.

Cc: Razvan Cojocaru <[email protected]>
Link: https://lore.kernel.org/netfilter-devel/[email protected]/
Link: https://lore.kernel.org/netfilter-devel/[email protected]/
Fixes: 1397af5 ("netfilter: conntrack: remove the percpu dying list")
Signed-off-by: Florian Westphal <[email protected]>
Signed-off-by: Pablo Neira Ayuso <[email protected]>
anthraxx pushed a commit that referenced this pull request Aug 24, 2025
[ Upstream commit 08a7efc ]

When testing F2FS with xfstests using UFS backed virtual disks the
kernel complains sometimes that f2fs_release_decomp_mem() calls
vm_unmap_ram() from an invalid context. Example trace from
f2fs/007 test:

f2fs/007 5s ...  [12:59:38][    8.902525] run fstests f2fs/007
[   11.468026] BUG: sleeping function called from invalid context at mm/vmalloc.c:2978
[   11.471849] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 68, name: irq/22-ufshcd
[   11.475357] preempt_count: 1, expected: 0
[   11.476970] RCU nest depth: 0, expected: 0
[   11.478531] CPU: 0 UID: 0 PID: 68 Comm: irq/22-ufshcd Tainted: G        W           6.16.0-rc5-xfstests-ufs-g40f92e79b0aa #9 PREEMPT(none)
[   11.478535] Tainted: [W]=WARN
[   11.478536] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   11.478537] Call Trace:
[   11.478543]  <TASK>
[   11.478545]  dump_stack_lvl+0x4e/0x70
[   11.478554]  __might_resched.cold+0xaf/0xbe
[   11.478557]  vm_unmap_ram+0x21/0xb0
[   11.478560]  f2fs_release_decomp_mem+0x59/0x80
[   11.478563]  f2fs_free_dic+0x18/0x1a0
[   11.478565]  f2fs_finish_read_bio+0xd7/0x290
[   11.478570]  blk_update_request+0xec/0x3b0
[   11.478574]  ? sbitmap_queue_clear+0x3b/0x60
[   11.478576]  scsi_end_request+0x27/0x1a0
[   11.478582]  scsi_io_completion+0x40/0x300
[   11.478583]  ufshcd_mcq_poll_cqe_lock+0xa3/0xe0
[   11.478588]  ufshcd_sl_intr+0x194/0x1f0
[   11.478592]  ufshcd_threaded_intr+0x68/0xb0
[   11.478594]  ? __pfx_irq_thread_fn+0x10/0x10
[   11.478599]  irq_thread_fn+0x20/0x60
[   11.478602]  ? __pfx_irq_thread_fn+0x10/0x10
[   11.478603]  irq_thread+0xb9/0x180
[   11.478605]  ? __pfx_irq_thread_dtor+0x10/0x10
[   11.478607]  ? __pfx_irq_thread+0x10/0x10
[   11.478609]  kthread+0x10a/0x230
[   11.478614]  ? __pfx_kthread+0x10/0x10
[   11.478615]  ret_from_fork+0x7e/0xd0
[   11.478619]  ? __pfx_kthread+0x10/0x10
[   11.478621]  ret_from_fork_asm+0x1a/0x30
[   11.478623]  </TASK>

This patch modifies in_task() check inside f2fs_read_end_io() to also
check if interrupts are disabled. This ensures that pages are unmapped
asynchronously in an interrupt handler.

Fixes: bff139b ("f2fs: handle decompress only post processing in softirq")
Signed-off-by: Jan Prusakowski <[email protected]>
Reviewed-by: Chao Yu <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Aug 24, 2025
[ Upstream commit 08a7efc ]

When testing F2FS with xfstests using UFS backed virtual disks the
kernel complains sometimes that f2fs_release_decomp_mem() calls
vm_unmap_ram() from an invalid context. Example trace from
f2fs/007 test:

f2fs/007 5s ...  [12:59:38][    8.902525] run fstests f2fs/007
[   11.468026] BUG: sleeping function called from invalid context at mm/vmalloc.c:2978
[   11.471849] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 68, name: irq/22-ufshcd
[   11.475357] preempt_count: 1, expected: 0
[   11.476970] RCU nest depth: 0, expected: 0
[   11.478531] CPU: 0 UID: 0 PID: 68 Comm: irq/22-ufshcd Tainted: G        W           6.16.0-rc5-xfstests-ufs-g40f92e79b0aa #9 PREEMPT(none)
[   11.478535] Tainted: [W]=WARN
[   11.478536] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   11.478537] Call Trace:
[   11.478543]  <TASK>
[   11.478545]  dump_stack_lvl+0x4e/0x70
[   11.478554]  __might_resched.cold+0xaf/0xbe
[   11.478557]  vm_unmap_ram+0x21/0xb0
[   11.478560]  f2fs_release_decomp_mem+0x59/0x80
[   11.478563]  f2fs_free_dic+0x18/0x1a0
[   11.478565]  f2fs_finish_read_bio+0xd7/0x290
[   11.478570]  blk_update_request+0xec/0x3b0
[   11.478574]  ? sbitmap_queue_clear+0x3b/0x60
[   11.478576]  scsi_end_request+0x27/0x1a0
[   11.478582]  scsi_io_completion+0x40/0x300
[   11.478583]  ufshcd_mcq_poll_cqe_lock+0xa3/0xe0
[   11.478588]  ufshcd_sl_intr+0x194/0x1f0
[   11.478592]  ufshcd_threaded_intr+0x68/0xb0
[   11.478594]  ? __pfx_irq_thread_fn+0x10/0x10
[   11.478599]  irq_thread_fn+0x20/0x60
[   11.478602]  ? __pfx_irq_thread_fn+0x10/0x10
[   11.478603]  irq_thread+0xb9/0x180
[   11.478605]  ? __pfx_irq_thread_dtor+0x10/0x10
[   11.478607]  ? __pfx_irq_thread+0x10/0x10
[   11.478609]  kthread+0x10a/0x230
[   11.478614]  ? __pfx_kthread+0x10/0x10
[   11.478615]  ret_from_fork+0x7e/0xd0
[   11.478619]  ? __pfx_kthread+0x10/0x10
[   11.478621]  ret_from_fork_asm+0x1a/0x30
[   11.478623]  </TASK>

This patch modifies in_task() check inside f2fs_read_end_io() to also
check if interrupts are disabled. This ensures that pages are unmapped
asynchronously in an interrupt handler.

Fixes: bff139b ("f2fs: handle decompress only post processing in softirq")
Signed-off-by: Jan Prusakowski <[email protected]>
Reviewed-by: Chao Yu <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Aug 24, 2025
[ Upstream commit 08a7efc ]

When testing F2FS with xfstests using UFS backed virtual disks the
kernel complains sometimes that f2fs_release_decomp_mem() calls
vm_unmap_ram() from an invalid context. Example trace from
f2fs/007 test:

f2fs/007 5s ...  [12:59:38][    8.902525] run fstests f2fs/007
[   11.468026] BUG: sleeping function called from invalid context at mm/vmalloc.c:2978
[   11.471849] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 68, name: irq/22-ufshcd
[   11.475357] preempt_count: 1, expected: 0
[   11.476970] RCU nest depth: 0, expected: 0
[   11.478531] CPU: 0 UID: 0 PID: 68 Comm: irq/22-ufshcd Tainted: G        W           6.16.0-rc5-xfstests-ufs-g40f92e79b0aa #9 PREEMPT(none)
[   11.478535] Tainted: [W]=WARN
[   11.478536] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   11.478537] Call Trace:
[   11.478543]  <TASK>
[   11.478545]  dump_stack_lvl+0x4e/0x70
[   11.478554]  __might_resched.cold+0xaf/0xbe
[   11.478557]  vm_unmap_ram+0x21/0xb0
[   11.478560]  f2fs_release_decomp_mem+0x59/0x80
[   11.478563]  f2fs_free_dic+0x18/0x1a0
[   11.478565]  f2fs_finish_read_bio+0xd7/0x290
[   11.478570]  blk_update_request+0xec/0x3b0
[   11.478574]  ? sbitmap_queue_clear+0x3b/0x60
[   11.478576]  scsi_end_request+0x27/0x1a0
[   11.478582]  scsi_io_completion+0x40/0x300
[   11.478583]  ufshcd_mcq_poll_cqe_lock+0xa3/0xe0
[   11.478588]  ufshcd_sl_intr+0x194/0x1f0
[   11.478592]  ufshcd_threaded_intr+0x68/0xb0
[   11.478594]  ? __pfx_irq_thread_fn+0x10/0x10
[   11.478599]  irq_thread_fn+0x20/0x60
[   11.478602]  ? __pfx_irq_thread_fn+0x10/0x10
[   11.478603]  irq_thread+0xb9/0x180
[   11.478605]  ? __pfx_irq_thread_dtor+0x10/0x10
[   11.478607]  ? __pfx_irq_thread+0x10/0x10
[   11.478609]  kthread+0x10a/0x230
[   11.478614]  ? __pfx_kthread+0x10/0x10
[   11.478615]  ret_from_fork+0x7e/0xd0
[   11.478619]  ? __pfx_kthread+0x10/0x10
[   11.478621]  ret_from_fork_asm+0x1a/0x30
[   11.478623]  </TASK>

This patch modifies in_task() check inside f2fs_read_end_io() to also
check if interrupts are disabled. This ensures that pages are unmapped
asynchronously in an interrupt handler.

Fixes: bff139b ("f2fs: handle decompress only post processing in softirq")
Signed-off-by: Jan Prusakowski <[email protected]>
Reviewed-by: Chao Yu <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Aug 24, 2025
[ Upstream commit 08a7efc ]

When testing F2FS with xfstests using UFS backed virtual disks the
kernel complains sometimes that f2fs_release_decomp_mem() calls
vm_unmap_ram() from an invalid context. Example trace from
f2fs/007 test:

f2fs/007 5s ...  [12:59:38][    8.902525] run fstests f2fs/007
[   11.468026] BUG: sleeping function called from invalid context at mm/vmalloc.c:2978
[   11.471849] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 68, name: irq/22-ufshcd
[   11.475357] preempt_count: 1, expected: 0
[   11.476970] RCU nest depth: 0, expected: 0
[   11.478531] CPU: 0 UID: 0 PID: 68 Comm: irq/22-ufshcd Tainted: G        W           6.16.0-rc5-xfstests-ufs-g40f92e79b0aa #9 PREEMPT(none)
[   11.478535] Tainted: [W]=WARN
[   11.478536] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   11.478537] Call Trace:
[   11.478543]  <TASK>
[   11.478545]  dump_stack_lvl+0x4e/0x70
[   11.478554]  __might_resched.cold+0xaf/0xbe
[   11.478557]  vm_unmap_ram+0x21/0xb0
[   11.478560]  f2fs_release_decomp_mem+0x59/0x80
[   11.478563]  f2fs_free_dic+0x18/0x1a0
[   11.478565]  f2fs_finish_read_bio+0xd7/0x290
[   11.478570]  blk_update_request+0xec/0x3b0
[   11.478574]  ? sbitmap_queue_clear+0x3b/0x60
[   11.478576]  scsi_end_request+0x27/0x1a0
[   11.478582]  scsi_io_completion+0x40/0x300
[   11.478583]  ufshcd_mcq_poll_cqe_lock+0xa3/0xe0
[   11.478588]  ufshcd_sl_intr+0x194/0x1f0
[   11.478592]  ufshcd_threaded_intr+0x68/0xb0
[   11.478594]  ? __pfx_irq_thread_fn+0x10/0x10
[   11.478599]  irq_thread_fn+0x20/0x60
[   11.478602]  ? __pfx_irq_thread_fn+0x10/0x10
[   11.478603]  irq_thread+0xb9/0x180
[   11.478605]  ? __pfx_irq_thread_dtor+0x10/0x10
[   11.478607]  ? __pfx_irq_thread+0x10/0x10
[   11.478609]  kthread+0x10a/0x230
[   11.478614]  ? __pfx_kthread+0x10/0x10
[   11.478615]  ret_from_fork+0x7e/0xd0
[   11.478619]  ? __pfx_kthread+0x10/0x10
[   11.478621]  ret_from_fork_asm+0x1a/0x30
[   11.478623]  </TASK>

This patch modifies in_task() check inside f2fs_read_end_io() to also
check if interrupts are disabled. This ensures that pages are unmapped
asynchronously in an interrupt handler.

Fixes: bff139b ("f2fs: handle decompress only post processing in softirq")
Signed-off-by: Jan Prusakowski <[email protected]>
Reviewed-by: Chao Yu <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Sep 20, 2025
[ Upstream commit 08a7efc ]

When testing F2FS with xfstests using UFS backed virtual disks the
kernel complains sometimes that f2fs_release_decomp_mem() calls
vm_unmap_ram() from an invalid context. Example trace from
f2fs/007 test:

f2fs/007 5s ...  [12:59:38][    8.902525] run fstests f2fs/007
[   11.468026] BUG: sleeping function called from invalid context at mm/vmalloc.c:2978
[   11.471849] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 68, name: irq/22-ufshcd
[   11.475357] preempt_count: 1, expected: 0
[   11.476970] RCU nest depth: 0, expected: 0
[   11.478531] CPU: 0 UID: 0 PID: 68 Comm: irq/22-ufshcd Tainted: G        W           6.16.0-rc5-xfstests-ufs-g40f92e79b0aa #9 PREEMPT(none)
[   11.478535] Tainted: [W]=WARN
[   11.478536] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   11.478537] Call Trace:
[   11.478543]  <TASK>
[   11.478545]  dump_stack_lvl+0x4e/0x70
[   11.478554]  __might_resched.cold+0xaf/0xbe
[   11.478557]  vm_unmap_ram+0x21/0xb0
[   11.478560]  f2fs_release_decomp_mem+0x59/0x80
[   11.478563]  f2fs_free_dic+0x18/0x1a0
[   11.478565]  f2fs_finish_read_bio+0xd7/0x290
[   11.478570]  blk_update_request+0xec/0x3b0
[   11.478574]  ? sbitmap_queue_clear+0x3b/0x60
[   11.478576]  scsi_end_request+0x27/0x1a0
[   11.478582]  scsi_io_completion+0x40/0x300
[   11.478583]  ufshcd_mcq_poll_cqe_lock+0xa3/0xe0
[   11.478588]  ufshcd_sl_intr+0x194/0x1f0
[   11.478592]  ufshcd_threaded_intr+0x68/0xb0
[   11.478594]  ? __pfx_irq_thread_fn+0x10/0x10
[   11.478599]  irq_thread_fn+0x20/0x60
[   11.478602]  ? __pfx_irq_thread_fn+0x10/0x10
[   11.478603]  irq_thread+0xb9/0x180
[   11.478605]  ? __pfx_irq_thread_dtor+0x10/0x10
[   11.478607]  ? __pfx_irq_thread+0x10/0x10
[   11.478609]  kthread+0x10a/0x230
[   11.478614]  ? __pfx_kthread+0x10/0x10
[   11.478615]  ret_from_fork+0x7e/0xd0
[   11.478619]  ? __pfx_kthread+0x10/0x10
[   11.478621]  ret_from_fork_asm+0x1a/0x30
[   11.478623]  </TASK>

This patch modifies in_task() check inside f2fs_read_end_io() to also
check if interrupts are disabled. This ensures that pages are unmapped
asynchronously in an interrupt handler.

Fixes: bff139b ("f2fs: handle decompress only post processing in softirq")
Signed-off-by: Jan Prusakowski <[email protected]>
Reviewed-by: Chao Yu <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Sep 21, 2025
[ Upstream commit ba1e942 ]

BUG: kernel NULL pointer dereference, address: 00000000000002ec
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP PTI
CPU: 28 UID: 0 PID: 343 Comm: kworker/28:1 Kdump: loaded Tainted: G        OE       6.17.0-rc2+ #9 NONE
Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
Workqueue: smc_hs_wq smc_listen_work [smc]
RIP: 0010:smc_ib_is_sg_need_sync+0x9e/0xd0 [smc]
...
Call Trace:
 <TASK>
 smcr_buf_map_link+0x211/0x2a0 [smc]
 __smc_buf_create+0x522/0x970 [smc]
 smc_buf_create+0x3a/0x110 [smc]
 smc_find_rdma_v2_device_serv+0x18f/0x240 [smc]
 ? smc_vlan_by_tcpsk+0x7e/0xe0 [smc]
 smc_listen_find_device+0x1dd/0x2b0 [smc]
 smc_listen_work+0x30f/0x580 [smc]
 process_one_work+0x18c/0x340
 worker_thread+0x242/0x360
 kthread+0xe7/0x220
 ret_from_fork+0x13a/0x160
 ret_from_fork_asm+0x1a/0x30
 </TASK>

If the software RoCE device is used, ibdev->dma_device is a null pointer.
As a result, the problem occurs. Null pointer detection is added to
prevent problems.

Fixes: 0ef69e7 ("net/smc: optimize for smc_sndbuf_sync_sg_for_device and smc_rmb_sync_sg_for_cpu")
Signed-off-by: Liu Jian <[email protected]>
Reviewed-by: Guangguan Wang <[email protected]>
Reviewed-by: Zhu Yanjun <[email protected]>
Reviewed-by: D. Wythe <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Sep 21, 2025
[ Upstream commit ba1e942 ]

BUG: kernel NULL pointer dereference, address: 00000000000002ec
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP PTI
CPU: 28 UID: 0 PID: 343 Comm: kworker/28:1 Kdump: loaded Tainted: G        OE       6.17.0-rc2+ #9 NONE
Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
Workqueue: smc_hs_wq smc_listen_work [smc]
RIP: 0010:smc_ib_is_sg_need_sync+0x9e/0xd0 [smc]
...
Call Trace:
 <TASK>
 smcr_buf_map_link+0x211/0x2a0 [smc]
 __smc_buf_create+0x522/0x970 [smc]
 smc_buf_create+0x3a/0x110 [smc]
 smc_find_rdma_v2_device_serv+0x18f/0x240 [smc]
 ? smc_vlan_by_tcpsk+0x7e/0xe0 [smc]
 smc_listen_find_device+0x1dd/0x2b0 [smc]
 smc_listen_work+0x30f/0x580 [smc]
 process_one_work+0x18c/0x340
 worker_thread+0x242/0x360
 kthread+0xe7/0x220
 ret_from_fork+0x13a/0x160
 ret_from_fork_asm+0x1a/0x30
 </TASK>

If the software RoCE device is used, ibdev->dma_device is a null pointer.
As a result, the problem occurs. Null pointer detection is added to
prevent problems.

Fixes: 0ef69e7 ("net/smc: optimize for smc_sndbuf_sync_sg_for_device and smc_rmb_sync_sg_for_cpu")
Signed-off-by: Liu Jian <[email protected]>
Reviewed-by: Guangguan Wang <[email protected]>
Reviewed-by: Zhu Yanjun <[email protected]>
Reviewed-by: D. Wythe <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Sep 21, 2025
[ Upstream commit ba1e942 ]

BUG: kernel NULL pointer dereference, address: 00000000000002ec
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP PTI
CPU: 28 UID: 0 PID: 343 Comm: kworker/28:1 Kdump: loaded Tainted: G        OE       6.17.0-rc2+ #9 NONE
Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
Workqueue: smc_hs_wq smc_listen_work [smc]
RIP: 0010:smc_ib_is_sg_need_sync+0x9e/0xd0 [smc]
...
Call Trace:
 <TASK>
 smcr_buf_map_link+0x211/0x2a0 [smc]
 __smc_buf_create+0x522/0x970 [smc]
 smc_buf_create+0x3a/0x110 [smc]
 smc_find_rdma_v2_device_serv+0x18f/0x240 [smc]
 ? smc_vlan_by_tcpsk+0x7e/0xe0 [smc]
 smc_listen_find_device+0x1dd/0x2b0 [smc]
 smc_listen_work+0x30f/0x580 [smc]
 process_one_work+0x18c/0x340
 worker_thread+0x242/0x360
 kthread+0xe7/0x220
 ret_from_fork+0x13a/0x160
 ret_from_fork_asm+0x1a/0x30
 </TASK>

If the software RoCE device is used, ibdev->dma_device is a null pointer.
As a result, the problem occurs. Null pointer detection is added to
prevent problems.

Fixes: 0ef69e7 ("net/smc: optimize for smc_sndbuf_sync_sg_for_device and smc_rmb_sync_sg_for_cpu")
Signed-off-by: Liu Jian <[email protected]>
Reviewed-by: Guangguan Wang <[email protected]>
Reviewed-by: Zhu Yanjun <[email protected]>
Reviewed-by: D. Wythe <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
anthraxx pushed a commit that referenced this pull request Sep 21, 2025
[ Upstream commit ba1e942 ]

BUG: kernel NULL pointer dereference, address: 00000000000002ec
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP PTI
CPU: 28 UID: 0 PID: 343 Comm: kworker/28:1 Kdump: loaded Tainted: G        OE       6.17.0-rc2+ #9 NONE
Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
Workqueue: smc_hs_wq smc_listen_work [smc]
RIP: 0010:smc_ib_is_sg_need_sync+0x9e/0xd0 [smc]
...
Call Trace:
 <TASK>
 smcr_buf_map_link+0x211/0x2a0 [smc]
 __smc_buf_create+0x522/0x970 [smc]
 smc_buf_create+0x3a/0x110 [smc]
 smc_find_rdma_v2_device_serv+0x18f/0x240 [smc]
 ? smc_vlan_by_tcpsk+0x7e/0xe0 [smc]
 smc_listen_find_device+0x1dd/0x2b0 [smc]
 smc_listen_work+0x30f/0x580 [smc]
 process_one_work+0x18c/0x340
 worker_thread+0x242/0x360
 kthread+0xe7/0x220
 ret_from_fork+0x13a/0x160
 ret_from_fork_asm+0x1a/0x30
 </TASK>

If the software RoCE device is used, ibdev->dma_device is a null pointer.
As a result, the problem occurs. Null pointer detection is added to
prevent problems.

Fixes: 0ef69e7 ("net/smc: optimize for smc_sndbuf_sync_sg_for_device and smc_rmb_sync_sg_for_cpu")
Signed-off-by: Liu Jian <[email protected]>
Reviewed-by: Guangguan Wang <[email protected]>
Reviewed-by: Zhu Yanjun <[email protected]>
Reviewed-by: D. Wythe <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
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