From owner-cvs-src@FreeBSD.ORG  Tue Jun 12 17:52:19 2007
Return-Path: <owner-cvs-src@FreeBSD.ORG>
X-Original-To: cvs-src@FreeBSD.org
Delivered-To: cvs-src@FreeBSD.org
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
	by hub.freebsd.org (Postfix) with ESMTP id 485F016A46C
	for <cvs-src@FreeBSD.org>; Tue, 12 Jun 2007 17:52:19 +0000 (UTC)
	(envelope-from julian@elischer.org)
Received: from outX.internet-mail-service.net (outX.internet-mail-service.net
	[216.240.47.247])
	by mx1.freebsd.org (Postfix) with ESMTP id 3677A13C457
	for <cvs-src@FreeBSD.org>; Tue, 12 Jun 2007 17:52:19 +0000 (UTC)
	(envelope-from julian@elischer.org)
Received: from mx0.idiom.com (HELO idiom.com) (216.240.32.160)
	by out.internet-mail-service.net (qpsmtpd/0.32) with ESMTP;
	Tue, 12 Jun 2007 10:52:18 -0700
Received: from julian-mac.elischer.org (nat.ironport.com [63.251.108.100])
	by idiom.com (Postfix) with ESMTP id 10F14125B4F;
	Tue, 12 Jun 2007 10:52:18 -0700 (PDT)
Message-ID: <466EDD51.8020504@elischer.org>
Date: Tue, 12 Jun 2007 10:52:17 -0700
From: Julian Elischer <julian@elischer.org>
User-Agent: Thunderbird 2.0.0.0 (Macintosh/20070326)
MIME-Version: 1.0
To: Jeff Roberson <jeff@FreeBSD.org>
References: <200706120724.l5C7Olwd088327@repoman.freebsd.org>
In-Reply-To: <200706120724.l5C7Olwd088327@repoman.freebsd.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org
Subject: Re: cvs commit: src/sys/sys proc.h src/sys/kern kern_thread.c
X-BeenThere: cvs-src@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: CVS commit messages for the src tree <cvs-src.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/cvs-src>,
	<mailto:cvs-src-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/cvs-src>
List-Post: <mailto:cvs-src@freebsd.org>
List-Help: <mailto:cvs-src-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/cvs-src>,
	<mailto:cvs-src-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 12 Jun 2007 17:52:19 -0000

Jeff Roberson wrote:
> jeff        2007-06-12 07:24:47 UTC
> 
>   FreeBSD src repository
> 
>   Modified files:
>     sys/sys              proc.h 
>     sys/kern             kern_thread.c 
>   Log:
>   Solve a complex exit race introduced with thread_lock:
>    - Add a count of exiting threads, p_exitthreads, to struct proc.
>    - Increment p_exithreads when we set the deadthread in thread_exit().
>    - When we thread_stash() a deadthread use an atomic to drop the count.
>    - Spin until the p_exithreads count reaches 0 in thread_wait().
>    - Lock the last exiting thread momentarily to be certain that it has
>      exited cpu_throw().

>    - Restructure thread_wait().  It does not need a loop as there will only
>      ever be one thread.

I think I was being paranoid.. also called "being on the safe side".

>   
>   Tested by:      moose@opera.com
>   Reported by:    kris, moose@opera.com
>   
>   Revision  Changes    Path
>   1.249     +33 -15    src/sys/kern/kern_thread.c
>   1.484     +1 -0      src/sys/sys/proc.h