[PATCH 5.7 236/265] mm/memcontrol.c: add missed css_put()

[Sasha Levin]

From: Muchun Song <songmuchun@xxxxxxxxxxxxx>

commit 3a98990ae2150277ed34d3b248c60e68bf2244b2 upstream.

We should put the css reference when memory allocation failed.

Link: http://lkml.kernel.org/r/20200614122653.98829-1-songmuchun@xxxxxxxxxxxxx
Fixes: f0a3a24b532d ("mm: memcg/slab: rework non-root kmem_cache lifecycle management")
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Acked-by: Roman Gushchin <guro@xxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Cc: Qian Cai <cai@xxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 mm/memcontrol.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1b05e25d8aef2..ef0e291a8cf46 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2790,8 +2790,10 @@ static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
 		return;
 
 	cw = kmalloc(sizeof(*cw), GFP_NOWAIT | __GFP_NOWARN);
-	if (!cw)
+	if (!cw) {
+		css_put(&memcg->css);
 		return;
+	}
 
 	cw->memcg = memcg;
 	cw->cachep = cachep;
-- 
2.25.1