diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index ed33cf7192d2..eed63f95e89d 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -2113,6 +2113,8 @@ static void __exit null_exit(void)
 
 	if (tag_set.ops)
 		blk_mq_free_tag_set(&tag_set);
+
+	mutex_destroy(&lock);
 }
 
 module_init(null_init);