FAILED: patch "[PATCH] mm/damon/sysfs: fix param_ctx leak on" failed to apply to 6.18-stable tree

FAILED: patch "[PATCH] mm/damon/sysfs: fix param_ctx leak on" failed to apply to 6.18-stable tree

[gregkh]

The patch below does not apply to the 6.18-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x 7fe000eb32904758a85e62f6ea9483f89d5dabfc
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026033007-talon-immature-91a3@gregkh' --subject-prefix 'PATCH 6.18.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 7fe000eb32904758a85e62f6ea9483f89d5dabfc Mon Sep 17 00:00:00 2001
From: Josh Law <objecting@objecting.org>
Date: Sat, 21 Mar 2026 10:54:24 -0700
Subject: [PATCH] mm/damon/sysfs: fix param_ctx leak on
 damon_sysfs_new_test_ctx() failure

Patch series "mm/damon/sysfs: fix memory leak and NULL dereference
issues", v4.

DAMON_SYSFS can leak memory under allocation failure, and do NULL pointer
dereference when a privileged user make wrong sequences of control.  Fix
those.


This patch (of 3):

When damon_sysfs_new_test_ctx() fails in damon_sysfs_commit_input(),
param_ctx is leaked because the early return skips the cleanup at the out
label.  Destroy param_ctx before returning.

Link: https://lkml.kernel.org/r/20260321175427.86000-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20260321175427.86000-2-sj@kernel.org
Fixes: f0c5118ebb0e ("mm/damon/sysfs: catch commit test ctx alloc failure")
Signed-off-by: Josh Law <objecting@objecting.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>	[6.18+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 576d1ddd736b..b573b9d60784 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1524,8 +1524,10 @@ static int damon_sysfs_commit_input(void *data)
 	if (IS_ERR(param_ctx))
 		return PTR_ERR(param_ctx);
 	test_ctx = damon_sysfs_new_test_ctx(kdamond->damon_ctx);
-	if (!test_ctx)
+	if (!test_ctx) {
+		damon_destroy_ctx(param_ctx);
 		return -ENOMEM;
+	}
 	err = damon_commit_ctx(test_ctx, param_ctx);
 	if (err)
 		goto out;

[PATCH 6.18.y] mm/damon/sysfs: fix param_ctx leak on damon_sysfs_new_test_ctx() failure

[SeongJae Park]

From: Josh Law <objecting@objecting.org>

Patch series "mm/damon/sysfs: fix memory leak and NULL dereference
issues", v4.

DAMON_SYSFS can leak memory under allocation failure, and do NULL pointer
dereference when a privileged user make wrong sequences of control.  Fix
those.

This patch (of 3):

When damon_sysfs_new_test_ctx() fails in damon_sysfs_commit_input(),
param_ctx is leaked because the early return skips the cleanup at the out
label.  Destroy param_ctx before returning.

Link: https://lkml.kernel.org/r/20260321175427.86000-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20260321175427.86000-2-sj@kernel.org
Fixes: f0c5118ebb0e ("mm/damon/sysfs: catch commit test ctx alloc failure")
Signed-off-by: Josh Law <objecting@objecting.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>	[6.18+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit 7fe000eb32904758a85e62f6ea9483f89d5dabfc)
Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index dec9f5d0d512..3d410f9213ed 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1476,8 +1476,10 @@ static int damon_sysfs_commit_input(void *data)
 	if (IS_ERR(param_ctx))
 		return PTR_ERR(param_ctx);
 	test_ctx = damon_new_ctx();
-	if (!test_ctx)
+	if (!test_ctx) {
+		damon_destroy_ctx(param_ctx);
 		return -ENOMEM;
+	}
 	err = damon_commit_ctx(test_ctx, param_ctx);
 	if (err)
 		goto out;
-- 
2.47.3