From owner-freebsd-current  Tue Feb 22  7:33:14 2000
Delivered-To: freebsd-current@freebsd.org
Received: from fgwmail7.fujitsu.co.jp (fgwmail7.fujitsu.co.jp [192.51.44.37])
	by hub.freebsd.org (Postfix) with ESMTP
	id 8728037B68C; Tue, 22 Feb 2000 07:33:09 -0800 (PST)
	(envelope-from shin@nd.net.fujitsu.co.jp)
Received: from m4.gw.fujitsu.co.jp by fgwmail7.fujitsu.co.jp (8.9.3/3.7W-MX0002-Fujitsu Gateway)
	id AAA23320; Wed, 23 Feb 2000 00:32:01 +0900 (JST)
	(envelope-from shin@nd.net.fujitsu.co.jp)
Received: from incapgw.fujitsu.co.jp by m4.gw.fujitsu.co.jp (8.9.3/3.7W-0002-Fujitsu Domain Master)
	id AAA10819; Wed, 23 Feb 2000 00:32:01 +0900 (JST)
Received: from localhost ([192.168.245.60]) by incapgw.fujitsu.co.jp (8.9.3/3.7W-0002)
	id AAA01669; Wed, 23 Feb 2000 00:31:59 +0900 (JST)
To: wollman@khavrinen.lcs.mit.edu
Cc: asmodai@bart.nl, freebsd-current@FreeBSD.ORG,
	freebsd-net@FreeBSD.ORG
Subject: Re: Panic (TCP)
In-Reply-To: <200002221505.KAA07676@khavrinen.lcs.mit.edu>
References: <20000221144858.O84100@lucifer.bart.nl>
	<20000222132327B.shin@nd.net.fujitsu.co.jp>
	<200002221505.KAA07676@khavrinen.lcs.mit.edu>
X-Mailer: Mew version 1.94 on Emacs 20.4 / Mule 4.0 (HANANOEN)
X-Prom-Mew: Prom-Mew 1.93.4 (procmail reader for Mew)
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Message-Id: <20000223003250I.shin@nd.net.fujitsu.co.jp>
Date: Wed, 23 Feb 2000 00:32:50 +0900
From: Yoshinobu Inoue <shin@nd.net.fujitsu.co.jp>
X-Dispatcher: imput version 990905(IM130)
Lines: 31
Sender: owner-freebsd-current@FreeBSD.ORG
Precedence: bulk
X-Loop: FreeBSD.ORG

> > If persist timer is working, and if it happen to timeout between
> > 			callout_reset(tp->tt_rexmt, tp->t_rxtcur,
> > 				      tcp_timer_rexmt, tp);
> > and
> > 				callout_stop(tp->tt_persist);
> > then the panic might happen at tcp_setpersist().
> 
> This should never happen, since this code is supposed to be running at
> splnet(), which is supposed to block timeouts.  Rather than papering
> over the problem, I'd like to understand how it's possible.

I also later thought so, but again I suspect that the part is
also one of the cause of the problem. Because as the value of
tp->t_rexmt at panic, retransmit timer also seemed to be
running at the time, and I can't find any other place which
might cause this situation.
Also I think anyway the patch is better to be applied.

My assumption might be wrong but I am now trying if I can
create some patch that make the problem very likely to happen.

Thanks,
Yoshinobu Inoue

> -GAWollman
> 
> --
> Garrett A. Wollman   | O Siem / We are all family / O Siem / We're all the same
> wollman@lcs.mit.edu  | O Siem / The fires of freedom 
> Opinions not those of| Dance in the burning flame
> MIT, LCS, CRS, or NSA|                     - Susan Aglukark and Chad Irschick


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-current" in the body of the message