Re: TCP-MD5 checksum failure on x86_64 SMP

Eric Dumazet
2010-05-07T15:18:11Z

OK, I found the second problem.

if/when IP route cache is invalidated, ip_queue_xmit() has to refetch a
route and calls sk_setup_caps(sk, &rt->u.dst), destroying the

sk->sk_route_caps &= ~NETIF_F_GSO_MASK

that MD5 desesperatly try to make all over its way (from
tcp_transmit_skb() for example)

So we send few bad packets, and everything is fine when
tcp_transmit_skb() is called again.

You get many errors on remote peer if you do

ip route flush cache