From owner-freebsd-current@FreeBSD.ORG  Tue Oct 19 21:25:01 2004
Return-Path: <owner-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 455AC16A4CE; Tue, 19 Oct 2004 21:25:01 +0000 (GMT)
Received: from mail.vicor-nb.com (bigwoop.vicor-nb.com [208.206.78.2])
	by mx1.FreeBSD.org (Postfix) with ESMTP
	id 1E5F643D49; Tue, 19 Oct 2004 21:25:01 +0000 (GMT)
	(envelope-from julian@elischer.org)
Received: from elischer.org (julian.vicor-nb.com [208.206.78.97])
	by mail.vicor-nb.com (Postfix) with ESMTP
	id EBDC67A425; Tue, 19 Oct 2004 14:25:00 -0700 (PDT)
Message-ID: <4175862C.6030403@elischer.org>
Date: Tue, 19 Oct 2004 14:25:00 -0700
From: Julian Elischer <julian@elischer.org>
User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.3.1) Gecko/20030516
X-Accept-Language: en, hu
MIME-Version: 1.0
To: John Baldwin <jhb@freebsd.org>
References: <20041019023713.GA1072@green.homeunix.org>
	<16757.4854.809996.993051@jerusalem.litteratus.org>
	<20041019160122.GC55255@xor.obsecurity.org>
	<200410191650.28544.jhb@FreeBSD.org>
In-Reply-To: <200410191650.28544.jhb@FreeBSD.org>
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
cc: freebsd-current@freebsd.org
cc: Robert Huff <roberthuff@rcn.com>
cc: Kris Kennaway <kris@obsecurity.org>
Subject: Re: WITNESS bug
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.1
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: Tue, 19 Oct 2004 21:25:01 -0000



John Baldwin wrote:

>On Tuesday 19 October 2004 12:01 pm, Kris Kennaway wrote:
>  
>
>>On Tue, Oct 19, 2004 at 09:13:26AM -0400, Robert Huff wrote:
>>    
>>
>>>Brian Fundakowski Feldman writes:
>>>      
>>>
>>>> You should never not run with WITNESS_SKIPSPIN if you use
>>>> modules.  Any spin mutexes not listed statically in the witness
>>>> code will cause your machine to immediately panic.
>>>>        
>>>>
>>>	If this is true (and I'm not disputing it), shouldn't it be
>>>noted in GENERIC and/or NOTES?  For that matter, what's the penalty
>>>for not automatically including it as part of WITNESS?
>>>      
>>>
>>Sometimes you don't want to use it, e.g. if you actually want to trace
>>spinlock operations with witness.
>>    
>>
>
>True spin mutexes should be rarely used anyways, so I don't think modules 
>needing spin mutexes is all that big of an issue.  Almost all mutexes should 
>just be regular mutexes.
>

netgraph uses a spin mutex for it's node locks

>
>  
>