memcg: avoid dangling reference count in creation failure.
When use_hierarchy is enabled, we acquire an extra reference count in
our parent during cgroup creation. We don't release it, though, if any
failure exist in the creation process.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Reported-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f4f41c3..60d28e3 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6196,6 +6196,8 @@
* call __mem_cgroup_free, so return directly
*/
mem_cgroup_put(memcg);
+ if (parent->use_hierarchy)
+ mem_cgroup_put(parent);
}
return error;
}