Re: [PATCH v2] poll: Fix use-after-free in poll_freewait()

[Christian Brauner]

On Wed, 14 Jun 2023 15:07:33 +0800, Lu Jialin wrote:
> We found a UAF bug in remove_wait_queue as follows:
> 
> ==================================================================
> BUG: KASAN: use-after-free in _raw_spin_lock_irqsave+0x71/0xe0
> Write of size 4 at addr ffff8881150d7b28 by task psi_trigger/15306
> Call Trace:
>  dump_stack+0x9c/0xd3
>  print_address_description.constprop.0+0x19/0x170
>  __kasan_report.cold+0x6c/0x84
>  kasan_report+0x3a/0x50
>  check_memory_region+0xfd/0x1f0
>  _raw_spin_lock_irqsave+0x71/0xe0
>  remove_wait_queue+0x26/0xc0
>  poll_freewait+0x6b/0x120
>  do_sys_poll+0x305/0x400
>  do_syscall_64+0x33/0x40
>  entry_SYSCALL_64_after_hwframe+0x61/0xc6
> 
> [...]

Applied to the vfs.misc branch of the vfs/vfs.git tree.
Patches in the vfs.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs.misc

[1/1] poll: Fix use-after-free in poll_freewait()
      https://git.kernel.org/vfs/vfs/c/e5f00a6f63bc