From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <48AFE498.2060805@domain.hid> Date: Sat, 23 Aug 2008 12:21:12 +0200 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <48AFCB3F.6070902@domain.hid> In-Reply-To: <48AFCB3F.6070902@domain.hid> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-core] Racy pse51_mutex_check_init? List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Xenomai-core@domain.hid 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 R=dnslookup T=remote_smtp: SMTP error from remote mailer after RCPT TO:: 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. > > > > If nothing, then I wonder if we actually have to iterate over the whole > > queue to find out whether a given object has been initialized and > > registered already or not. Can't this be encoded differently? > > > > BTW, shadow_mutex.mutex is a kernel pointer sitting in a user-reachable > > memory region? Why not using a handle here, like the native skin does? > > Won't that allow to resolve the issue above as well? This has been so from the beginning, and I did not change it. -- Gilles.