2 files changed, 5 insertions, 2 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 435f08dac8bf..861037070f66 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 fd150e3a2567..40ba05061a4f 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 @@ retry:
                 goto retry;
 out:
         read_unlock(&tasklist_lock);
-        cgroup_unlock();
 }
 #endif