[PATCH 6.19 279/342] mm/damon/sysfs: fix param_ctx leak on damon_sysfs_new_test_ctx() failure

Greg Kroah-Hartman
2026-03-31T16:43:16Z

From: Josh Law <objecting@objecting.org>

commit 7fe000eb32904758a85e62f6ea9483f89d5dabfc upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
mm/damon/sysfs.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1526,8 +1526,10 @@ static int damon_sysfs_commit_input(void
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;