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From: Oleksandr Natalenko <oleksandr@natalenko.name>
To: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Patrick McHardy <kaber@trash.net>,
	Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
	James Morris <jmorris@namei.org>,
	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
	"David S. Miller" <davem@davemloft.net>,
	Yuchung Cheng <ycheng@google.com>
Subject: [REGRESSION] tcp/ipv4: kernel panic because of (possible) division by zero
Date: Mon, 21 Dec 2015 22:25:30 +0200	[thread overview]
Message-ID: <26396443.iDTTxgChSj@spock> (raw)

Commit 3759824da87b30ce7a35b4873b62b0ba38905ef5 (tcp: PRR uses CRB mode by 
default and SS mode conditionally) introduced changes to net/ipv4/tcp_input.c 
tcp_cwnd_reduction() that, possibly, cause division by zero, and therefore, 
kernel panic in interrupt handler [1].

Reverting 3759824da87b30ce7a35b4873b62b0ba38905ef5 seems to fix the issue.

I'm able to reproduce the issue on 4.3.0–4.3.3 once per several day 
(occasionally).

What could be done to help in debugging this issue?

Regards,
  Oleksandr.

[1] http://i.piccy.info/
i9/6f5cb187c4ff282d189f78c63f95af43/1450729403/283985/951663/panic.jpg

             reply	other threads:[~2015-12-21 20:25 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-21 20:25 Oleksandr Natalenko [this message]
2015-12-22  2:10 ` [REGRESSION] tcp/ipv4: kernel panic because of (possible) division by zero Yuchung Cheng
2015-12-22 20:13   ` Oleksandr Natalenko
2016-01-06 16:50   ` Oleksandr Natalenko
2016-01-06 18:19     ` Yuchung Cheng
2016-01-06 18:43       ` Yuchung Cheng
2016-01-06 18:49         ` Oleksandr Natalenko
2016-01-09 17:34         ` Oleksandr Natalenko
2016-01-10 10:23         ` Oleksandr Natalenko
2016-01-10 14:48           ` Neal Cardwell
2016-01-10 14:54             ` Neal Cardwell
2016-01-10 14:57               ` Oleksandr Natalenko
2016-01-10 14:57             ` Oleksandr Natalenko
2016-01-10 17:29               ` Neal Cardwell
2016-01-10 17:50                 ` Oleksandr Natalenko
2016-01-10 18:00                   ` Neal Cardwell
2016-01-10 21:56                 ` Oleksandr Natalenko
2016-01-11 18:47                   ` Neal Cardwell
2016-01-11 23:26                     ` Oleksandr Natalenko

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