From owner-svn-src-all@FreeBSD.ORG  Wed Sep 29 02:42:40 2010
Return-Path: <owner-svn-src-all@FreeBSD.ORG>
Delivered-To: svn-src-all@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 1A1B0106564A;
	Wed, 29 Sep 2010 02:42:40 +0000 (UTC)
	(envelope-from davidxu@freebsd.org)
Received: from freefall.freebsd.org (freefall.freebsd.org
	[IPv6:2001:4f8:fff6::28])
	by mx1.freebsd.org (Postfix) with ESMTP id DFC1F8FC27;
	Wed, 29 Sep 2010 02:42:39 +0000 (UTC)
Received: from [127.0.0.1] (localhost [127.0.0.1])
	by freefall.freebsd.org (8.14.4/8.14.4) with ESMTP id o8T2gbd7027871;
	Wed, 29 Sep 2010 02:42:38 GMT (envelope-from davidxu@freebsd.org)
Message-ID: <4CA3181E.6030000@freebsd.org>
Date: Wed, 29 Sep 2010 10:42:38 +0000
From: David Xu <davidxu@freebsd.org>
User-Agent: Thunderbird 2.0.0.24 (X11/20100630)
MIME-Version: 1.0
To: Jung-uk Kim <jkim@freebsd.org>
References: <201009280457.o8S4vuS9060037@svn.freebsd.org>
	<201009281202.22555.jkim@FreeBSD.org>
	<201009281220.12278.jkim@FreeBSD.org>
	<201009281829.13253.jkim@FreeBSD.org>
In-Reply-To: <201009281829.13253.jkim@FreeBSD.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org,
	src-committers@freebsd.org, John Baldwin <jhb@freebsd.org>
Subject: Re: svn commit: r213241 - in head: include lib/libthr/thread
X-BeenThere: svn-src-all@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: "SVN commit messages for the entire src tree \(except for &quot;
	user&quot; and &quot; projects&quot; \)" <svn-src-all.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-all>,
	<mailto:svn-src-all-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-all>
List-Post: <mailto:svn-src-all@freebsd.org>
List-Help: <mailto:svn-src-all-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-all>,
	<mailto:svn-src-all-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 29 Sep 2010 02:42:40 -0000

Jung-uk Kim wrote:
> On Tuesday 28 September 2010 12:20 pm, Jung-uk Kim wrote:
>> On Tuesday 28 September 2010 12:02 pm, Jung-uk Kim wrote:
>>> On Tuesday 28 September 2010 09:31 am, John Baldwin wrote:
>>>> On Tuesday, September 28, 2010 12:57:56 am David Xu wrote:
>>>>> Author: davidxu
>>>>> Date: Tue Sep 28 04:57:56 2010
>>>>> New Revision: 213241
>>>>> URL: http://svn.freebsd.org/changeset/base/213241
>>>>>
>>>>> Log:
>>>>>   In current code, statically initialized and destroyed
>>>>> object have same null value, the code can not distinguish
>>>>> between them, to fix the problem, now a destroyed object is
>>>>> assigned to a non-null value, and it will be rejected by some
>>>>> pthread functions. PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP is
>>>>> changed to number 1, so that adaptive mutex can be statically
>>>>> initialized correctly.
>>>> Does this fix PR threads/150889 then?
>>> It seems it does.
>> Unfortunately, it seems to have a regression:
>>
>> %cat test.c
>> #include <pthread.h>
>> #include <stdio.h>
>>
>> static pthread_cond_t	static_cond = PTHREAD_COND_INITIALIZER;
>> static pthread_mutex_t	static_mutex = PTHREAD_MUTEX_INITIALIZER;
>>
>> int
>> main(void)
>> {
>>
>> 	// pthread_mutex_lock(&static_mutex);
>> 	printf("%d\n", pthread_cond_wait(&static_cond, &static_mutex));
>> 	pthread_mutex_unlock(&static_mutex);
>>
>> 	return (0);
>> }
>> %cc -o test test.c -pthread
>> %./test
>> Segmentation fault (core dumped)
>>
>> pthread_cond_wait(3) had to return EPERM here. :-(
> 
> I realized it is a libthr "feature" to catch real application bugs and 
> to increase performance by not checking rare conditions, I guess. :-/
> 
> Sorry for the noise,
> 
> Jung-uk Kim
> 
I think your example is legal, I might add checking back, however, it
would return two codes, EINVAL and EPERM.