--- x/net/8021q/vlan.c
+++ y/net/8021q/vlan.c
@@ -614,6 +614,9 @@ static int vlan_ioctl_handler(struct net
 		break;
 
 	case ADD_VLAN_CMD:
+		err = -EINVAL;
+		if (is_vlan_dev(dev))
+			break;
 		err = -EPERM;
 		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 			break;