diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 7347eb29524d..64551b0aa51e 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1139,6 +1139,7 @@ static void blkcg_fill_root_iostats(void)
 		blkg_iostat_set(&blkg->iostat.cur, &tmp);
 		u64_stats_update_end_irqrestore(&blkg->iostat.sync, flags);
 	}
+	class_dev_iter_exit(&iter);
 }
 
 static void blkcg_print_one_stat(struct blkcg_gq *blkg, struct seq_file *s)