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From: Vladimir Davydov <vdavydov@virtuozzo.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@kernel.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH] mm: memcontrol: fix possible css ref leak on oom
Date: Mon, 23 May 2016 19:02:10 +0300	[thread overview]
Message-ID: <1464019330-7579-1-git-send-email-vdavydov@virtuozzo.com> (raw)

mem_cgroup_oom may be invoked multiple times while a process is handling
a page fault, in which case current->memcg_in_oom will be overwritten
leaking the previously taken css reference.

Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
---
 mm/memcontrol.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5b48cd25951b..ef8797d34039 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1608,7 +1608,7 @@ static void memcg_oom_recover(struct mem_cgroup *memcg)
 
 static void mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
 {
-	if (!current->memcg_may_oom)
+	if (!current->memcg_may_oom || current->memcg_in_oom)
 		return;
 	/*
 	 * We are in the middle of the charge context here, so we
-- 
2.1.4

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             reply	other threads:[~2016-05-23 16:02 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-23 16:02 Vladimir Davydov [this message]
2016-05-23 17:44 ` Michal Hocko
2016-05-24  8:43   ` Vladimir Davydov
2016-05-24  8:47     ` Michal Hocko
2016-05-24  9:01       ` Vladimir Davydov
2016-05-24  9:22         ` Michal Hocko
2016-05-24 10:05           ` Vladimir Davydov
2016-05-24 11:31             ` Michal Hocko
2016-05-27 17:36 ` Johannes Weiner
2016-05-29  9:11   ` Vladimir Davydov
2016-05-30  7:26   ` Michal Hocko

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