diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 435f08dac8bf6c02a2b71580f8de9dc652fa914f..861037070f6672b3fd9e69d4aa0a796980fb2c7c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -51,6 +51,7 @@ static int really_do_swap_account __initdata = 1; /* for remember boot option*/
 #define do_swap_account		(0)
 #endif
 
+static DEFINE_MUTEX(memcg_tasklist);	/* can be hold under cgroup_mutex */
 
 /*
  * Statistics for memory cgroup.
@@ -827,7 +828,9 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
 
 		if (!nr_retries--) {
 			if (oom) {
+				mutex_lock(&memcg_tasklist);
 				mem_cgroup_out_of_memory(mem_over_limit, gfp_mask);
+				mutex_unlock(&memcg_tasklist);
 				mem_over_limit->last_oom_jiffies = jiffies;
 			}
 			goto nomem;
@@ -2211,10 +2214,12 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss,
 				struct cgroup *old_cont,
 				struct task_struct *p)
 {
+	mutex_lock(&memcg_tasklist);
 	/*
 	 * FIXME: It's better to move charges of this process from old
 	 * memcg to new memcg. But it's just on TODO-List now.
 	 */
+	mutex_unlock(&memcg_tasklist);
 }
 
 struct cgroup_subsys mem_cgroup_subsys = {
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index fd150e3a2567a137eef87c6c76772fd0c34fd112..40ba05061a4fbc8a43d3eb046a58fe756748cd06 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -429,7 +429,6 @@ void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask)
 	unsigned long points = 0;
 	struct task_struct *p;
 
-	cgroup_lock();
 	read_lock(&tasklist_lock);
 retry:
 	p = select_bad_process(&points, mem);
@@ -444,7 +443,6 @@ void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask)
 		goto retry;
 out:
 	read_unlock(&tasklist_lock);
-	cgroup_unlock();
 }
 #endif