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 <[email protected]> Reported-by: Michal Hocko <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Tejun Heo <[email protected]> Cc: Hiroyuki Kamezawa <[email protected]> Cc: Johannes Weiner <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
chewitt · Feb 24, 2013 · e4715f0 · e4715f0
1 parent 692e89a
commit e4715f0
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
@@ -6196,6 +6196,8 @@ mem_cgroup_css_online(struct cgroup *cont)
 		 * call __mem_cgroup_free, so return directly
 		 */
 		mem_cgroup_put(memcg);
+		if (parent->use_hierarchy)
+			mem_cgroup_put(parent);
 	}
 	return error;
 }