From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752617AbXCUMFi (ORCPT ); Wed, 21 Mar 2007 08:05:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752266AbXCUMFi (ORCPT ); Wed, 21 Mar 2007 08:05:38 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:57577 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752613AbXCUMFf (ORCPT ); Wed, 21 Mar 2007 08:05:35 -0400 From: "Rafael J. Wysocki" To: "Eric W. Biederman" Subject: Re: [linux-pm] 2.6.21-rc4-mm1: freezing of processes broken Date: Wed, 21 Mar 2007 13:08:32 +0100 User-Agent: KMail/1.9.5 Cc: Jiri Slaby , Andrew Morton , Pavel Machek , linux-pm@lists.osdl.org, linux-kernel@vger.kernel.org, Sukadev Bhattiprolu , Oleg Nesterov , Nigel Cunningham References: <20070319205623.299d0378.akpm@linux-foundation.org> <200703210149.33240.rjw@sisk.pl> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200703211308.33295.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday, 21 March 2007 02:23, Eric W. Biederman wrote: > "Rafael J. Wysocki" writes: > > > On Tuesday, 20 March 2007 22:06, Rafael J. Wysocki wrote: > >> On Tuesday, 20 March 2007 21:58, Jiri Slaby wrote: > >> > Rafael J. Wysocki napsal(a): > >> > > Actually, the problem is 100% reproducible on my system too and I doubt > > it's > >> > > caused by the recent freezer patches. > >> > > >> > I don't know what exactly do you mean by recent, but 2.6.21-rc3-mm2 works > >> > for me. > >> > >> Thanks for the confirmation. > >> > >> The patches I was talking about had already been in 2.6.21-rc3-mm2, so the > >> reason of this failure must be different. > > > > Bisection shows that the freezing of processes has been broken by one of the > > patches: > > > > remove-the-likelypid-check-in-copy_process.patch > > Grr. Oleg's review of remove-the-likelypid-check-in-copy-process > showed it to be questionable (and it was just an optimization) > so we can get rid of that one easily. > > Although all it did that was really questionable was add > the idle process to the global process list and bump a process > count when we forked the idle process. Not dramatically dangerous > things. I think this patch is the culprit, though, as it seems that the freezer tries to freeze the idle process and fails. Yesterday I didn't have the time to figure out the exact reason, I'll try to look at it later today. > > use-task_pgrp-task_session-in-copy_process.patch > > As I recall that patch was pretty trivial, and shouldn't have > anything to do with the freezer. The process freezer doesn't care > about pids does it? No, it doesn't, at least not directly. I'll try to run the kernel with this change and without remove-the-likelypid-check-in-copy_process.patch . Greetings, Rafael