Re: [PATCH] fuse: fix uninit-value in fuse_dentry_revalidate()

[Miklos Szeredi]

On Mon, 16 Feb 2026 at 15:48, Luis Henriques <luis@xxxxxxxxxx> wrote:
>
> fuse_dentry_revalidate() may be called with a dentry that didn't had
> ->d_time initialised.  The issue was found with KMSAN, where lookup_open()
> calls __d_alloc(), followed by d_revalidate(), as shown below:
>
> =====================================================
> BUG: KMSAN: uninit-value in fuse_dentry_revalidate+0x150/0x13d0 fs/fuse/dir.c:394
>  fuse_dentry_revalidate+0x150/0x13d0 fs/fuse/dir.c:394
>  d_revalidate fs/namei.c:1030 [inline]
>  lookup_open fs/namei.c:4405 [inline]
>  open_last_lookups fs/namei.c:4583 [inline]
>  path_openat+0x1614/0x64c0 fs/namei.c:4827
>  do_file_open+0x2aa/0x680 fs/namei.c:4859
> [...]
>
> Uninit was created at:
>  slab_post_alloc_hook mm/slub.c:4466 [inline]
>  slab_alloc_node mm/slub.c:4788 [inline]
>  kmem_cache_alloc_lru_noprof+0x382/0x1280 mm/slub.c:4807
>  __d_alloc+0x55/0xa00 fs/dcache.c:1740
>  d_alloc_parallel+0x99/0x2740 fs/dcache.c:2604
>  lookup_open fs/namei.c:4398 [inline]
>  open_last_lookups fs/namei.c:4583 [inline]
>  path_openat+0x135f/0x64c0 fs/namei.c:4827
>  do_file_open+0x2aa/0x680 fs/namei.c:4859
> [...]
> =====================================================
>
> Reported-by: syzbot+fdebb2dc960aa56c600a@xxxxxxxxxxxxxxxxxxxxxxxxx
> Closes: https://lore.kernel.org/all/69917e0d.050a0220.340abe.02e2.GAE@xxxxxxxxxx
> Fixes: 2396356a945b ("fuse: add more control over cache invalidation behaviour")
> Signed-off-by: Luis Henriques <luis@xxxxxxxxxx>

Applied, thanks.

Miklos