[PATCH v4] damon/sysfs: Fix possible memleak on damon_sysfs_add_target.

SeongJae Park
2022-09-26T16:06:26Z

From: Levi Yun <ppbuk5246@gmail.com>

When damon_sysfs_add_target couldn't find proper task,
New allocated damon_target structure isn't registered yet,
So, it's impossible to free new allocated one by
damon_sysfs_destroy_targets.

By calling daemon_add_target as soon as allocating new target, Fix this
possible memory leak.

Fixes: a61ea561c871 ("mm/damon/sysfs: link DAMON for virtual address spaces monitoring")
Cc: <stable@vger.kernel.org> # 5.17.x
Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
---

Changes from v3
(https://lore.kernel.org/damon/20220925234327.26345-1-ppbuk5246@gmail.com/)
- Fix Fixes: tag
- Add patch changelog

Changes from v2
(https://lore.kernel.org/damon/20220925234053.26090-1-ppbuk5246@gmail.com/)
- Add Fixes: and Cc: stable

Changes from v1
(https://lore.kernel.org/damon/20220925140257.23431-1-ppbuk5246@gmail.com/)
- Do damon_add_target() earlier instead of explicitly freeing the object

mm/damon/sysfs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 455215a5c059..9f1219a67e3f 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -2172,12 +2172,12 @@ static int damon_sysfs_add_target(struct damon_sysfs_target *sys_target,

if (!t)
return -ENOMEM;
+ damon_add_target(ctx, t);
if (damon_target_has_pid(ctx)) {
t->pid = find_get_pid(sys_target->pid);
if (!t->pid)
goto destroy_targets_out;
}
- damon_add_target(ctx, t);
err = damon_sysfs_set_regions(t, sys_target->regions);
if (err)
goto destroy_targets_out;
--
2.25.1