queue-6.18/xfs-fix-error-pointer-dereference.patch

From cddfa648f1ab99e30e91455be19cd5ade26338c2 Mon Sep 17 00:00:00 2001
From: Ethan Tidmore <ethantidmore06@gmail.com>
Date: Thu, 19 Feb 2026 21:38:25 -0600
Subject: xfs: Fix error pointer dereference

From: Ethan Tidmore <ethantidmore06@gmail.com>

commit cddfa648f1ab99e30e91455be19cd5ade26338c2 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/xfs/scrub/orphanage.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/fs/xfs/scrub/orphanage.c
+++ b/fs/xfs/scrub/orphanage.c
@@ -445,6 +445,11 @@ xrep_adoption_check_dcache(
 		return 0;
 
 	d_child = try_lookup_noperm(&qname, d_orphanage);
+	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);
 
@@ -482,7 +487,7 @@ xrep_adoption_zap_dcache(
 		return;
 
 	d_child = try_lookup_noperm(&qname, d_orphanage);
-	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));