diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2a1f7847b6ad..7bc30707d0c6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1238,10 +1238,21 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg)
 	struct task_struct *p;
 
 	p = find_lock_task_mm(task);
-	if (!p)
-		return 0;
-	curr = try_get_mem_cgroup_from_mm(p->mm);
-	task_unlock(p);
+	if (p) {
+		curr = try_get_mem_cgroup_from_mm(p->mm);
+		task_unlock(p);
+	} else {
+		/*
+		 * All threads may have already detached their mm's, but the oom
+		 * killer still needs to detect if they have already been oom
+		 * killed to prevent needlessly killing additional tasks.
+		 */
+		task_lock(task);
+		curr = mem_cgroup_from_task(task);
+		if (curr)
+			css_get(&curr->css);
+		task_unlock(task);
+	}
 	if (!curr)
 		return 0;
 	/*