Re: [PATCH 6.12.y] xfs: Fix error pointer dereference

["Darrick J. Wong" <djwong@kernel.org>]

On Mon, Mar 09, 2026 at 09:49:55AM -0400, Sasha Levin wrote:
> From: Ethan Tidmore <ethantidmore06@gmail.com>
> 
> [ Upstream commit cddfa648f1ab99e30e91455be19cd5ade26338c2 ]
> 
> The function try_lookup_noperm() can return an error pointer and is not
> checked for one.
> 
> Add checks for error pointer in xrep_adoption_check_dcache() and
> xrep_adoption_zap_dcache().
> 
> Detected by Smatch:
> fs/xfs/scrub/orphanage.c:449 xrep_adoption_check_dcache() error:
> 'd_child' dereferencing possible ERR_PTR()
> 
> fs/xfs/scrub/orphanage.c:485 xrep_adoption_zap_dcache() error:
> 'd_child' dereferencing possible ERR_PTR()
> 
> Fixes: 73597e3e42b4 ("xfs: ensure dentry consistency when the orphanage adopts a file")
> Cc: stable@vger.kernel.org # v6.16
> Signed-off-by: Ethan Tidmore <ethantidmore06@gmail.com>
> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
> Reviewed-by: Nirjhar Roy (IBM) <nirjhar.roy.lists@gmail.com>
> Signed-off-by: Carlos Maiolino <cem@kernel.org>
> [ adapted try_lookup_noperm() calls to d_hash_and_lookup() ]
> Signed-off-by: Sasha Levin <sashal@kernel.org>

Backport looks good to me,
Acked-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  fs/xfs/scrub/orphanage.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/xfs/scrub/orphanage.c b/fs/xfs/scrub/orphanage.c
> index 7148d8362db83..46171f61eda43 100644
> --- a/fs/xfs/scrub/orphanage.c
> +++ b/fs/xfs/scrub/orphanage.c
> @@ -443,6 +443,11 @@ xrep_adoption_check_dcache(
>  		return 0;
>  
>  	d_child = d_hash_and_lookup(d_orphanage, &qname);
> +	if (IS_ERR(d_child)) {
> +		dput(d_orphanage);
> +		return PTR_ERR(d_child);
> +	}
> +
>  	if (d_child) {
>  		trace_xrep_adoption_check_child(sc->mp, d_child);
>  
> @@ -480,7 +485,7 @@ xrep_adoption_zap_dcache(
>  		return;
>  
>  	d_child = d_hash_and_lookup(d_orphanage, &qname);
> -	while (d_child != NULL) {
> +	while (!IS_ERR_OR_NULL(d_child)) {
>  		trace_xrep_adoption_invalidate_child(sc->mp, d_child);
>  
>  		ASSERT(d_is_negative(d_child));
> -- 
> 2.51.0
>