Hi. I've applied your test patch but it doesn't fix the issue for me since the warning is still there.
Were you able to reproduce it? On pondělí 11. září 2017 1:59:02 CEST Neal Cardwell wrote: > Thanks for the detailed report! > > I suspect this is due to the following commit, which happened between > 4.10 and 4.11: > > 89fe18e44f7e tcp: extend F-RTO to catch more spurious timeouts > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/? > id=89fe18e44f7e > > This commit expanded the set of scenarios where we would undo a > CA_Loss cwnd reduction and return to TCP_CA_Open, but did not include > a check to see if there were any in-flight retransmissions. I think we > need a fix like the following: > > diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c > index 659d1baefb2b..730a2de9d2b0 100644 > --- a/net/ipv4/tcp_input.c > +++ b/net/ipv4/tcp_input.c > @@ -2439,7 +2439,7 @@ static bool tcp_try_undo_loss(struct sock *sk, > bool frto_undo) > { > struct tcp_sock *tp = tcp_sk(sk); > > - if (frto_undo || tcp_may_undo(tp)) { > + if ((frto_undo || tcp_may_undo(tp)) && !tp->retrans_out) { > tcp_undo_cwnd_reduction(sk, true); > > DBGUNDO(sk, "partial loss"); > > I will try a packetdrill test to see if I can reproduce this issue and > verify the fix. > > thanks, > neal
