diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 9e190d220e98..8b7f306ec976 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -2147,12 +2147,13 @@ again:
 
 	ret = nbd_start_device(nbd);
 out:
-	mutex_unlock(&nbd->config_lock);
 	if (!ret) {
 		set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags);
 		refcount_inc(&nbd->config_refs);
 		nbd_connect_reply(info, nbd->index);
 	}
+	mutex_unlock(&nbd->config_lock);
+
 	nbd_config_put(nbd);
 	if (put_dev)
 		nbd_put(nbd);