From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: 2.6.21-rc4-mm1: freezing of processes broken Date: Wed, 21 Mar 2007 13:08:32 +0100 Message-ID: <200703211308.33295.rjw@sisk.pl> References: <20070319205623.299d0378.akpm@linux-foundation.org> <200703210149.33240.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: "Eric W. Biederman" Cc: Sukadev Bhattiprolu , Jiri Slaby , Pavel Machek , Andrew Morton , linux-pm@lists.osdl.org, linux-kernel@vger.kernel.org, Nigel Cunningham , Oleg Nesterov List-Id: linux-pm@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 o= f 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 tri= es 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