Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751818AbWIGSlu (ORCPT ); Thu, 7 Sep 2006 14:41:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751833AbWIGSlu (ORCPT ); Thu, 7 Sep 2006 14:41:50 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:52355 "EHLO ebiederm.dsl.xmission.com") by vger.kernel.org with ESMTP id S1751818AbWIGSlt (ORCPT ); Thu, 7 Sep 2006 14:41:49 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Jean Delvare Cc: Andrew Morton , Oleg Nesterov , KAMEZAWA Hiroyuki , linux-kernel@vger.kernel.org, ak@suse.de Subject: Re: [PATCH] proc: readdir race fix (take 3) References: <20060825182943.697d9d81.kamezawa.hiroyu@jp.fujitsu.com> <200609071031.33855.jdelvare@suse.de> <200609072007.25239.jdelvare@suse.de> Date: Thu, 07 Sep 2006 12:40:46 -0600 In-Reply-To: <200609072007.25239.jdelvare@suse.de> (Jean Delvare's message of "Thu, 7 Sep 2006 20:07:24 +0200") Message-ID: User-Agent: Gnus/5.110004 (No Gnus v0.4) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1983 Lines: 45 Jean Delvare writes: > On Thursday 7 September 2006 15:57, Eric W. Biederman wrote: >> Jean Delvare writes: >> > I'll now apply Oleg's fix and see if things get better. > > After 8 hours of stress testing on two machines, no crash and no freeze. > So Oleg's fix seems to do the trick. Thanks Oleg :) > > I'll keep the patches applied on both machines, even without stress tests > it is still better to make sure nothing bad happens in the long run. > >> > "My" test program forks 1000 children who sleep for 1 second then >> > look for themselves in /proc, warn if they can't find themselves, and >> > exit. So basically the idea is that the process list will shrink very >> > rapidly at the same moment every child does readdir(/proc). >> > >> > I attached the test program, I take no credit (nor shame) for it, it >> > was provided to me by IBM (possibly on behalf of one of their own >> > customers) as a way to demonstrate and reproduce the original >> > readdir(/proc) race bug. >> >> Ok. So whatever is creating lots of child threads that tripped you >> up is probably peculiar to the environment on your laptop. > > There's nothing really special running on this laptop. Slackware 10.2 with > xterm, firefox, sylpheed, xchat, and that's about it. At least one of the > crashes I had yesterday happened when I was actively using firefox, I > can't tell for the other one. Well firefox is threaded so that may be enough. It takes a threaded program to be able to trigger it. > The difference with the system where no problem was observed may be that > the laptop has a preemptive kernel, and the desktop hasn't. I suspect that just has the potential to make the window bigger. Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/