Re: [PATCH] fs: writeback: fix use-after-free in __mark_inode_dirty()

[Christian Brauner]

On Mon, 28 Jul 2025 18:07:15 +0800, Jiufei Xue wrote:
> An use-after-free issue occurred when __mark_inode_dirty() get the
> bdi_writeback that was in the progress of switching.
> 
> CPU: 1 PID: 562 Comm: systemd-random- Not tainted 6.6.56-gb4403bd46a8e #1
> ......
> pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : __mark_inode_dirty+0x124/0x418
> lr : __mark_inode_dirty+0x118/0x418
> sp : ffffffc08c9dbbc0
> ........
> Call trace:
>  __mark_inode_dirty+0x124/0x418
>  generic_update_time+0x4c/0x60
>  file_modified+0xcc/0xd0
>  ext4_buffered_write_iter+0x58/0x124
>  ext4_file_write_iter+0x54/0x704
>  vfs_write+0x1c0/0x308
>  ksys_write+0x74/0x10c
>  __arm64_sys_write+0x1c/0x28
>  invoke_syscall+0x48/0x114
>  el0_svc_common.constprop.0+0xc0/0xe0
>  do_el0_svc+0x1c/0x28
>  el0_svc+0x40/0xe4
>  el0t_64_sync_handler+0x120/0x12c
>  el0t_64_sync+0x194/0x198
> 
> [...]

Applied to the vfs.fixes branch of the vfs/vfs.git tree.
Patches in the vfs.fixes 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.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

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

[1/1] fs: writeback: fix use-after-free in __mark_inode_dirty()
      https://git.kernel.org/vfs/vfs/c/f8371b50ceaa