Re: [PATCH v3] dcache: unpoison the inline name buffer in __d_alloc()

[Christian Brauner]

On Fri, 18 Sep 2026 23:42:04 +0100, Drif Abdelmalek Mohamed Said wrote:
> syzbot reported:
> 
>     BUG: KMSAN: uninit-value in dentry_string_cmp fs/dcache.c:291 [inline]
>     BUG: KMSAN: uninit-value in dentry_cmp fs/dcache.c:322 [inline]
>     BUG: KMSAN: uninit-value in __d_lookup_rcu+0x37d/0x5e0 fs/dcache.c:2522
> 
>      dentry_string_cmp fs/dcache.c:291 [inline]
>      dentry_cmp fs/dcache.c:322 [inline]
>      __d_lookup_rcu+0x37d/0x5e0 fs/dcache.c:2522
>      lookup_fast+0x194/0xa40 fs/namei.c:1854
>      lookup_fast_for_open fs/namei.c:4545 [inline]
>      open_last_lookups fs/namei.c:4579 [inline]
>      path_openat+0x9ef/0x6540 fs/namei.c:4856
>      do_file_open+0x2aa/0x680 fs/namei.c:4888
>      do_sys_openat2+0x17c/0x390 fs/open.c:1395
>      do_sys_open fs/open.c:1401 [inline]
>      __do_sys_openat fs/open.c:1417 [inline]
>      __se_sys_openat fs/open.c:1412 [inline]
>      __x64_sys_openat+0x240/0x300 fs/open.c:1412
>      x64_sys_call+0x2445/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:258
>      do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>      do_syscall_64+0x15d/0x3c0 arch/x86/entry/syscall_64.c:94
>      entry_SYSCALL_64_after_hwframe+0x77/0x7f
> 
> [...]

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] dcache: unpoison the inline name buffer in __d_alloc()
      https://git.kernel.org/vfs/vfs/c/76d8e697242e