[PATCH 3/3] mm/damon/sysfs-schemes: handle tried region directory allocation failure

[SeongJae Park <sj@kernel.org>]

DAMON sysfs interface's before_damos_apply callback
(damon_sysfs_before_damos_apply()), which creates the DAMOS tried
regions for each DAMOS action applied region, is not handling the
allocation failure for the sysfs directory data.  As a result, NULL
pointer derefeence is possible.  Fix it by handling the case.

Fixes: f1d13cacabe1 ("mm/damon/sysfs: implement DAMOS tried regions update command")
Cc: <stable@vger.kernel.org> # 6.2.x
Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-schemes.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 7413cb35c5a9..be667236b8e6 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -1826,6 +1826,8 @@ static int damon_sysfs_before_damos_apply(struct damon_ctx *ctx,
 		return 0;
 
 	region = damon_sysfs_scheme_region_alloc(r);
+	if (!region)
+		return 0;
 	list_add_tail(&region->list, &sysfs_regions->regions_list);
 	sysfs_regions->nr_regions++;
 	if (kobject_init_and_add(&region->kobj,
-- 
2.34.1