--- a/sys/dev/netif/sn/if_sn.c
+++ b/sys/dev/netif/sn/if_sn.c
@@ -161,7 +161,10 @@ sn_attach(device_t dev)
 	int		j;
 	int		error;
 
-	sn_activate(dev);
+	error = sn_activate(dev);
+	if (error)
+		return (error);
 
 	snstop(sc);