From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760312Ab1IKSda (ORCPT ); Sun, 11 Sep 2011 14:33:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39808 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753787Ab1IKSd2 (ORCPT ); Sun, 11 Sep 2011 14:33:28 -0400 Date: Sun, 11 Sep 2011 20:29:53 +0200 From: Oleg Nesterov To: Tejun Heo Cc: "Rafael J. Wysocki" , matthltc@us.ibm.com, paul@paulmenage.org, containers@lists.linux-foundation.org, linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] freezer: fix wait_event_freezable/__thaw_task races Message-ID: <20110911182953.GA22941@redhat.com> References: <20110905162012.GA4445@redhat.com> <20110906032846.GA18425@mtj.dyndns.org> <20110906151836.GA15568@redhat.com> <20110906152539.GA16899@redhat.com> <20110906155332.GF18425@mtj.dyndns.org> <20110907182156.GA13909@redhat.com> <20110907182217.GB13909@redhat.com> <20110908010530.GD3987@mtj.dyndns.org> <20110908175926.GA26986@redhat.com> <20110911015431.GK29319@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110911015431.GK29319@htj.dyndns.org> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On 09/11, Tejun Heo wrote: > > On Thu, Sep 08, 2011 at 07:59:26PM +0200, Oleg Nesterov wrote: > > > > Yeap, with freezable_with_signal gone, this looks correct & simpler to > > > me > > > > I don't really understand this... set_freezable_with_signal() has a > > lot of problems, yes... But even if it wasn't removed this fix makes > > sense anyway, afaics. > > > > If freezable_with_signal caller does wait_event_freezable_timeout(), > > __retval becomes -ERESTARTSYS after freeze_task(). The next iteration > > will return 0 with the KERN_ERR message from schedule_timeout(). > > Hmmm... but with the change, if a kthread gets TIF_SIGPENDING from > freezer and then thawed, it would not enter try_to_freeze() and thus > won't clear TIF_SIGPENDING. Ah yes, you are right, thanks. But once again, please note that in this case wait_event_freezable_timeout() is broken anyway. > > > but it would be nice if you can sprinkle some documentation while > > > at it. :) > > > > But they already have the comment ;) What can I add? > > Proper /** - */ comment w/ return value documentation? :P I already noticed a long ago you like the comments too much ;) OK, will do. Oleg.