diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c8336e8f8df064c9a1ecdbb8055a785b3481d4f2..da07784dde875247dd7b2c47cd25eacb42780921 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1158,7 +1158,15 @@ mem_cgroup_iter_load(struct mem_cgroup_reclaim_iter *iter,
 	if (iter->last_dead_count == *sequence) {
 		smp_rmb();
 		position = iter->last_visited;
-		if (position && !css_tryget(&position->css))
+
+		/*
+		 * We cannot take a reference to root because we might race
+		 * with root removal and returning NULL would end up in
+		 * an endless loop on the iterator user level when root
+		 * would be returned all the time.
+		 */
+		if (position && position != root &&
+				!css_tryget(&position->css))
 			position = NULL;
 	}
 	return position;
@@ -1167,9 +1175,11 @@ mem_cgroup_iter_load(struct mem_cgroup_reclaim_iter *iter,
 static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter *iter,
 				   struct mem_cgroup *last_visited,
 				   struct mem_cgroup *new_position,
+				   struct mem_cgroup *root,
 				   int sequence)
 {
-	if (last_visited)
+	/* root reference counting symmetric to mem_cgroup_iter_load */
+	if (last_visited && last_visited != root)
 		css_put(&last_visited->css);
 	/*
 	 * We store the sequence count from the time @last_visited was
@@ -1244,7 +1254,8 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
 		memcg = __mem_cgroup_iter_next(root, last_visited);
 
 		if (reclaim) {
-			mem_cgroup_iter_update(iter, last_visited, memcg, seq);
+			mem_cgroup_iter_update(iter, last_visited, memcg, root,
+					seq);
 
 			if (!memcg)
 				iter->generation++;