diff --git a/[refs] b/[refs]
index 5a0fd9113cc0..1f650d302a49 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 1e50cc9022d6c0b9175d804573e3f401d00d1381
+refs/heads/master: c0bd3f63ce01a1757dbce6373122a05fbf99ced7
diff --git a/trunk/mm/memcontrol.c b/trunk/mm/memcontrol.c
index e44fb0fbb80e..575203ae2109 100644
--- a/trunk/mm/memcontrol.c
+++ b/trunk/mm/memcontrol.c
@@ -1024,9 +1024,7 @@ static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page)
 		return NULL;
 
 	pc = lookup_page_cgroup(page);
-	/*
-	 * Used bit of swapcache is solid under page lock.
-	 */
+	lock_page_cgroup(pc);
 	if (PageCgroupUsed(pc)) {
 		mem = pc->mem_cgroup;
 		if (mem && !css_tryget(&mem->css))
@@ -1040,6 +1038,7 @@ static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page)
 			mem = NULL;
 		rcu_read_unlock();
 	}
+	unlock_page_cgroup(pc);
 	return mem;
 }