Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754665Ab3IYFw3 (ORCPT ); Wed, 25 Sep 2013 01:52:29 -0400 Received: from mail-ob0-f180.google.com ([209.85.214.180]:43843 "EHLO mail-ob0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751107Ab3IYFw1 (ORCPT ); Wed, 25 Sep 2013 01:52:27 -0400 MIME-Version: 1.0 In-Reply-To: <7588112.eXrFpITlCh@vostro.rjw.lan> References: <5917186.DMyAa9ofOj@amdc1032> <7346644.tueXegsfXu@vostro.rjw.lan> <20130820122727.GC3926@htj.dyndns.org> <7588112.eXrFpITlCh@vostro.rjw.lan> Date: Wed, 25 Sep 2013 14:52:26 +0900 X-Google-Sender-Auth: Pdqj79uIzmZTReLE1UdnJrQrNYM Message-ID: Subject: Re: [RFC PATCH] freezer: allow killing of frozen tasks From: Kyungmin Park To: "Rafael J. Wysocki" , Tejun Heo Cc: Bartlomiej Zolnierkiewicz , Pavel Machek , linux-pm@vger.kernel.org, LKML , Colin Cross Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1916 Lines: 42 On Tue, Aug 20, 2013 at 9:41 PM, Rafael J. Wysocki wrote: > On Tuesday, August 20, 2013 08:27:27 AM Tejun Heo wrote: >> On Tue, Aug 20, 2013 at 02:34:14PM +0200, Rafael J. Wysocki wrote: >> > On Tuesday, August 20, 2013 08:22:00 AM Tejun Heo wrote: >> > > On Tue, Aug 20, 2013 at 02:30:18PM +0200, Rafael J. Wysocki wrote: >> > > > > So, I don't think we can simply turn TASK_UNITERRUPTIBLE to >> > > > > TASK_KILLABLE at this point. We really need to strictly define where >> > > > > a task can freeze before being able to do anything like this. >> > > > >> > > > But we could do that for user space tasks I suppose? >> > > >> > > Even for userland tasks, we don't know where the task is stuck at. I >> > > think there are enough freeze points in the kernel which are in the >> > > middle of something which can be used by userland tasks excuting some >> > > syscall. We need to collect all those sites into well defined trap >> > > points before doing this. >> > >> > OK, thanks! >> >> I scanned through try_to_freeze() users and it seems like we don't >> have that many which can be hit by userland tasks. I think it should >> be doable to audit all the users, remove the ones which can be invoked >> by userland and make try_to_freeze() whine loudly if it's running off >> a userland task except from well-defined spots. > > Which might be worth doing anyway to be sure we know what's going on. > >> Anyways, we need to ensure that userland task doesn't get stuck deep in the >> kernel before allowing this. > > Agreed. Are there any update? we need this feature to kill frozen app easily. Don't need to thaw app to kill. Thank you, Kyungmin Park -- 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/