From owner-freebsd-current@FreeBSD.ORG  Mon Apr  3 09:07:37 2006
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
X-Original-To: freebsd-current@freebsd.org
Delivered-To: freebsd-current@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 0097F16A420
	for <freebsd-current@freebsd.org>; Mon,  3 Apr 2006 09:07:37 +0000 (UTC)
	(envelope-from rwatson@FreeBSD.org)
Received: from cyrus.watson.org (cyrus.watson.org [209.31.154.42])
	by mx1.FreeBSD.org (Postfix) with ESMTP id ABCB843D45
	for <freebsd-current@freebsd.org>; Mon,  3 Apr 2006 09:07:36 +0000 (GMT)
	(envelope-from rwatson@FreeBSD.org)
Received: from fledge.watson.org (fledge.watson.org [209.31.154.41])
	by cyrus.watson.org (Postfix) with ESMTP id 135CD46B89;
	Mon,  3 Apr 2006 05:07:36 -0400 (EDT)
Date: Mon, 3 Apr 2006 10:07:36 +0100 (BST)
From: Robert Watson <rwatson@FreeBSD.org>
X-X-Sender: robert@fledge.watson.org
To: Ganbold <ganbold@micom.mng.net>
In-Reply-To: <4430DF4E.1060600@micom.mng.net>
Message-ID: <20060403100516.C76562@fledge.watson.org>
References: <4430DF4E.1060600@micom.mng.net>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
Cc: freebsd-current@freebsd.org
Subject: Re: page fault on today's CURRENT (tcp_usr_accept)
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
	<freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>, 
	<mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 03 Apr 2006 09:07:37 -0000


On Mon, 3 Apr 2006, Ganbold wrote:

> I've got page fault on today's CURRENT.
>
> Fatal trap 12: page fault while in kernel mode
> fault virtual address                  = 0xa0
> fault code                                    = supervisor write, page not 
> present
> instructon pointer                     = 0x20: 0xc062bbde
> stack pointer                              = 0x28: 0xcc8efc10
> frame pointer                              = 0x28: 0xcc8efc2c
> code segment                              = base 0x0, limit 0xfffff, type 
> 0x1b
>                                                     =DPL 0, pres 1, def32 1, 
> gran 1
> processor eflags                        = interrupt enabled, resume, IOPL = 0
> current process                        = 435 (smbd)
> [thread pid 435 tid 100039]
> stopped at tcp_usr_accept+0xd6:    cmpxchgl   %ecx, 0xa0(%ebx)
>
> I'm running samba (samba-3.0.21b,1) on this test machine and there is no 
> load.
>
> FreeBSD gw.micom.mng.net 7.0-CURRENT FreeBSD 7.0-CURRENT #16: Mon Apr  3 
> 14:15:48 ULAST 2006     tsgan@gw.micom.mng.net:/usr/obj/usr/src/sys/GW  i386

Is there any chance you can extract a stack trace, as well as file names and 
line numbers for the trace?  If you have a core, could I get you to dump the 
state from the relevant frames?  The above looks like a NULL pointer 
derefernece in tcp_usr_accept().  Since I've moderately exercised the accept() 
path on TCP, it's presumably a race condition of some sort.

Thanks!

Robert N M Watson