Re: [PATCH net-next 0/8] tcp: receiver changes

[Jakub Kicinski <kuba@kernel.org>]

On Tue, 15 Jul 2025 15:52:33 +0200 Paolo Abeni wrote:
> On 7/15/25 3:33 PM, Jakub Kicinski wrote:
> > On Tue, 15 Jul 2025 06:28:29 -0700 Jakub Kicinski wrote:  
> >> # (null):17: error handling packet: timing error: expected outbound packet at 0.074144 sec but happened at -1752585909.757339 sec; tolerance 0.004000 sec
> >> # script packet:  0.074144 S. 0:0(0) ack 1 <mss 1460,nop,wscale 0>
> >> # actual packet: -1752585909.757339 S.0 0:0(0) ack 1 <mss 1460,nop,wscale 0>  
> > 
> > This is definitely compiler related, I rebuilt with clang and the build
> > error goes away. Now I get a more sane failure:
> > 
> > # tcp_rcv_big_endseq.pkt:41: error handling packet: timing error: expected outbound packet at 1.230105 sec but happened at 1.190101 sec; tolerance 0.005046 sec
> > # script packet:  1.230105 . 1:1(0) ack 54001 win 0 
> > # actual packet:  1.190101 . 1:1(0) ack 54001 win 0 
> > 
> > $ gcc --version
> > gcc (GCC) 15.1.1 20250521 (Red Hat 15.1.1-2)
> > 
> > I don't understand why the ack is supposed to be delayed, should we
> > just do this? (I think Eric is OOO, FWIW)
> > 
> > diff --git a/tools/testing/selftests/net/packetdrill/tcp_rcv_big_endseq.pkt b/tools/testing/selftests/net/packetdrill/tcp_rcv_big_endseq.pkt
> > index 7e170b94fd36..3848b419e68c 100644
> > --- a/tools/testing/selftests/net/packetdrill/tcp_rcv_big_endseq.pkt
> > +++ b/tools/testing/selftests/net/packetdrill/tcp_rcv_big_endseq.pkt
> > @@ -38,7 +38,7 @@
> >  
> >  // If queue is empty, accept a packet even if its end_seq is above wup + rcv_wnd
> >    +0 < P. 4001:54001(50000) ack 1 win 257
> > -  +.040 > .  1:1(0) ack 54001 win 0
> > +  +0 > .  1:1(0) ack 54001 win 0
> >  
> >  // Check LINUX_MIB_BEYOND_WINDOW has been incremented 3 times.
> >  +0 `nstat | grep TcpExtBeyondWindow | grep -q " 3 "`  
> 
> The above looks sane to me, but I Neal or Willem ack would be appreciated.

Posted officially here to get it queued to the CI already:
https://lore.kernel.org/all/20250715142849.959444-1-kuba@kernel.org/