From 92c3d8b61579fc6a2f1a0050980d6aaf9e8c1e16 Mon Sep 17 00:00:00 2001
From: Muchun Song <songmuchun@bytedance.com>
Date: Thu, 15 Oct 2020 15:10:21 +0800
Subject: [PATCH] mm/memcontrol.c: add missed css_put()

mainline inclusion
from mainline-v5.8-rc3
commit 3a98990ae2150277ed34d3b248c60e68bf2244b2
category: bugfix
bugzilla: 34611
CVE: NA

-------------------------------------------------

We should put the css reference when memory allocation failed.

Link: http://lkml.kernel.org/r/20200614122653.98829-1-songmuchun@bytedance.com
Fixes: f0a3a24b532d ("mm: memcg/slab: rework non-root kmem_cache lifecycle management")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 mm/memcontrol.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6e5c798c7c77..be50582ae13e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2654,8 +2654,10 @@ 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;
-- 
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