From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <48AFE7AE.4000804@domain.hid>
Date: Sat, 23 Aug 2008 12:34:22 +0200
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
MIME-Version: 1.0
References: <48AFCB3F.6070902@domain.hid> <48AFE498.2060805@domain.hid>
In-Reply-To: <48AFE498.2060805@domain.hid>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Subject: Re: [Xenomai-core] Racy pse51_mutex_check_init?
List-Id: "Xenomai life and development \(bug reports, patches,
	discussions\)" <xenomai.xenomai.org>
List-Unsubscribe: <https://mail.gna.org/listinfo/xenomai-core>,
	<mailto:xenomai-core-request@domain.hid>
List-Archive: </public/xenomai-core>
List-Post: <mailto:xenomai@xenomai.org>
List-Help: <mailto:xenomai-core-request@domain.hid>
List-Subscribe: <https://mail.gna.org/listinfo/xenomai-core>,
	<mailto:xenomai-core-request@domain.hid>
To: Xenomai-core@domain.hid

Gilles Chanteperdrix wrote:
> Hi Jan,
> 
> Please do not use my address at gmail, gna does not want me to post from
> this address:
> 
> 2008-08-23 12:10:19 1KWq4T-0000zD-9E ** xenomai@xenomai.org <Xenomai-core@domain.hid
>> R=dnslookup T=remote_smtp: SMTP error from remote mailer after RCPT TO:<Xenomai-
> core@domain.hid>: host mail.gna.org [88.191.250.46]: 550 rejected because gmail.com i
> s in a black list at dsn.rfc-ignorant.org
> 
> so, here is a repost of my answer:
> 
> Jan Kiszka wrote:
>>> Hi Gilles,
>>>
>>> trying to understand the cb_read/write lock usage, some question came up
>>> here: What prevents that the mutexq iteration in pse51_mutex_check_init
>>> races against pse51_mutex_destroy_internal?
> 
> Well, I am afraid the mechanism used is not 100% safe. Anyway, the aim
> is to catch most of invalid usages, it seems we can not catch them all.

No, it works, because pthread_mutex_destroy will not be able to get the
write lock is the lock is read-locked.

-- 
					    Gilles.