Messages in this thread | | | From | SeongJae Park <> | Subject | Re: Re: [PATCH 2/3] tcp: Reduce SYN resend delay if a suspicous ACK is received | Date | Fri, 31 Jan 2020 23:17:55 +0100 |
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On Fri, 31 Jan 2020 17:11:35 -0500 Neal Cardwell <ncardwell@google.com> wrote:
> On Fri, Jan 31, 2020 at 1:12 PM Eric Dumazet <eric.dumazet@gmail.com> wrote: > > > > > > > > On 1/31/20 7:10 AM, Neal Cardwell wrote: > > > On Fri, Jan 31, 2020 at 7:25 AM <sjpark@amazon.com> wrote: > > >> > > >> From: SeongJae Park <sjpark@amazon.de> > > >> > > >> When closing a connection, the two acks that required to change closing > > >> socket's status to FIN_WAIT_2 and then TIME_WAIT could be processed in > > >> reverse order. This is possible in RSS disabled environments such as a > > >> connection inside a host. [...] > > I looked into fixing this, but my quick reading of the Linux > tcp_rcv_state_process() code is that it should behave correctly and > that a connection in FIN_WAIT_1 that receives a FIN/ACK should move to > TIME_WAIT. > > SeongJae, do you happen to have a tcpdump trace of the problematic > sequence where the "process A" ends up in FIN_WAIT_2 when it should be > in TIME_WAIT?
Hi Neal,
Yes, I have. You can get it from the previous discussion for this patchset (https://lore.kernel.org/bpf/20200129171403.3926-1-sjpark@amazon.com/). As it also has a reproducer program and how I got the tcpdump trace, I believe you could get your own trace, too. If you have any question or need help, feel free to let me know. :)
Thanks, SeongJae Park
> > If I have time I will try to construct a packetdrill case to verify > the behavior in this case. > > thanks, > neal > > >
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