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From: Oleksandr Natalenko <oleksandr@natalenko.name>
To: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>,
	"David S. Miller" <davem@davemloft.net>,
	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
	Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
	Netdev <netdev@vger.kernel.org>
Subject: Re: [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c
Date: Tue, 19 Sep 2017 13:04:10 +0200	[thread overview]
Message-ID: <13e86265b8db3a5b1f1eaf8135ff4510@natalenko.name> (raw)
In-Reply-To: <CAK6E8=e7SE-M4r2nJ8K_FoDMVcN2xYdtw=MetvD5MvXMm9iA1Q@mail.gmail.com>

Hi.

18.09.2017 23:40, Yuchung Cheng wrote:
> I assume this kernel does not have the patch that Neal proposed in his
> first reply?

Correct.

> The main warning needs to be triggered by another peculiar SACK that
> kicks the sender into recovery again (after undo). Please let it run
> longer if possible to see if we can get both. But the new data does
> indicate the we can (validly) be in CA_Open with retrans_out > 0.

OK, here it is:

===
» LC_TIME=C jctl -kb | grep RIP
…
Sep 19 12:54:03 defiant kernel: RIP: 
0010:tcp_undo_cwnd_reduction+0xbd/0xd0
Sep 19 12:54:22 defiant kernel: RIP: 
0010:tcp_undo_cwnd_reduction+0xbd/0xd0
Sep 19 12:54:25 defiant kernel: RIP: 
0010:tcp_undo_cwnd_reduction+0xbd/0xd0
Sep 19 12:56:00 defiant kernel: RIP: 
0010:tcp_fastretrans_alert+0x7c8/0x990
Sep 19 12:57:07 defiant kernel: RIP: 
0010:tcp_undo_cwnd_reduction+0xbd/0xd0
Sep 19 12:57:14 defiant kernel: RIP: 
0010:tcp_undo_cwnd_reduction+0xbd/0xd0
Sep 19 12:58:04 defiant kernel: RIP: 
0010:tcp_undo_cwnd_reduction+0xbd/0xd0
…
===

Note timestamps — two types of warning are distant in time, so didn't 
happen at once.

While still running this kernel, anything else I can check for you?

  reply	other threads:[~2017-09-19 11:04 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-10 20:53 [REGRESSION] Warning in tcp_fastretrans_alert() of net/ipv4/tcp_input.c Oleksandr Natalenko
2017-09-10 23:59 ` Neal Cardwell
2017-09-15  5:03   ` Oleksandr Natalenko
2017-09-15 14:03     ` Neal Cardwell
2017-09-15 19:04       ` Oleksandr Natalenko
2017-09-17 18:43         ` Oleksandr Natalenko
2017-09-18 17:18           ` Yuchung Cheng
2017-09-18 17:51             ` Yuchung Cheng
2017-09-18 17:59               ` Oleksandr Natalenko
2017-09-18 18:01                 ` Yuchung Cheng
2017-09-18 18:04                   ` Oleksandr Natalenko
2017-09-18 20:41                   ` Oleksandr Natalenko
2017-09-18 20:46                   ` Oleksandr Natalenko
2017-09-18 21:40                     ` Yuchung Cheng
2017-09-19 11:04                       ` Oleksandr Natalenko [this message]
2017-09-19 18:16                         ` Yuchung Cheng
2017-09-19 16:05                       ` Oleksandr Natalenko
  -- strict thread matches above, loose matches on Subject: below --
2017-09-21  1:46 Roman Gushchin
2017-09-21 17:07 ` Yuchung Cheng
     [not found]   ` <CAK6E8=cGF+xKiixRVvA=3PVPA7OQta9hVLTgCbKgvYf3e9Eu-A@mail.gmail.com>
2017-09-26 13:10     ` Roman Gushchin
2017-09-27  0:12       ` Yuchung Cheng
2017-09-27  0:18         ` Yuchung Cheng
2017-09-28  8:14           ` Oleksandr Natalenko
2017-09-28 23:36             ` Yuchung Cheng
2017-10-26  2:07               ` Alexei Starovoitov
2017-10-26  5:37                 ` Yuchung Cheng
2017-10-27 20:38                   ` Eric Dumazet
2017-11-06 22:27                     ` Yuchung Cheng
2017-11-10 13:15                       ` Oleksandr Natalenko
2017-11-10 13:40                         ` Oleksandr Natalenko

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