Commit 
9af3912ec9e30509b76cb376abb65a4d8af27df3 ("[NET] Move DF check
to ip_forward") added a new check to send ICMP fragmentation needed
for large packets.
Unlike the check in ip_finish_output(), it doesn't check for GSO.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
        if (opt->is_strictroute && rt->rt_dst != rt->rt_gateway)
                goto sr_failed;
 
-       if (unlikely(skb->len > dst_mtu(&rt->u.dst) &&
+       if (unlikely(skb->len > dst_mtu(&rt->u.dst) && !skb_is_gso(skb) &&
                     (ip_hdr(skb)->frag_off & htons(IP_DF))) && !skb->local_df) {
                IP_INC_STATS(IPSTATS_MIB_FRAGFAILS);
                icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,