From: Eric Dumazet <[email protected]> Date: Mon, 27 Jun 2016 17:38:50 +0200
> From: Eric Dumazet <[email protected]> > > Arjun reported a bug in TCP stack and bisected it to a recent commit. > > In case where we process SACK, we can coalesce multiple skbs > into fat ones (tcp_shift_skb_data()), to lower write queue > overhead, because we do not expect to retransmit these packets. > > However, SACK reneging can happen, forcing the sender to retransmit > all these packets. If skb->len is above 64KB, we then send buggy > IP packets that could hang TSO engine on cxgb4. > > Neal suggested to use tcp_tso_autosize() instead of tp->gso_segs > so that we cook packets of optimal size vs TCP/pacing. > > Thanks to Arjun for reporting the bug and running the tests ! > > Fixes: 10d3be569243 ("tcp-tso: do not split TSO packets at retransmit time") > Signed-off-by: Eric Dumazet <[email protected]> > Reported-by: Arjun V <[email protected]> > Tested-by: Arjun V <[email protected]> Applied.
