--- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -944,7 +944,7 @@ static netdev_tx_t ipip6_tunnel_xmit(str } if (tunnel->parms.iph.daddr) - skb_dst_update_pmtu(skb, mtu); + skb_dst_update_pmtu_no_confirm(skb, mtu); if (skb->len > mtu && !skb_is_gso(skb)) { icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);