diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index d6283b3f5db50674d18ae485970f1e24ed44569d..9cc48d1d7abb161f3d11ceebefbdb5c77d479932 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -387,6 +387,9 @@ static void blkg_destroy_all(struct request_queue *q)
 		blkg_destroy(blkg);
 		spin_unlock(&blkcg->lock);
 	}
+
+	q->root_blkg = NULL;
+	q->root_rl.blkg = NULL;
 }
 
 /*