From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752387Ab1HVRmz (ORCPT ); Mon, 22 Aug 2011 13:42:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:17037 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751997Ab1HVRmx (ORCPT ); Mon, 22 Aug 2011 13:42:53 -0400 Date: Mon, 22 Aug 2011 19:39:49 +0200 From: Oleg Nesterov To: Bruno =?iso-8859-1?Q?Pr=E9mont?= Cc: Daniel Lezcano , "Serge E. Hallyn" , akpm@linux-foundation.org, containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/2] Send a SIGCHLD to the init's pid namespace parent when reboot Message-ID: <20110822173949.GA13242@redhat.com> References: <1313094241-3674-1-git-send-email-daniel.lezcano@free.fr> <20110814161707.GB30846@redhat.com> <20110814213642.GB13799@hallyn.com> <20110815144744.GA9660@redhat.com> <4E4DA461.8030006@free.fr> <20110819152416.GA17034@redhat.com> <4E524B73.3050704@free.fr> <20110822154448.GA8527@redhat.com> <20110822183134.10390b46@neptune.home> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20110822183134.10390b46@neptune.home> 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 On 08/22, Bruno Prémont wrote: > > On Mon, 22 August 2011 Oleg Nesterov wrote: > > On 08/22, Daniel Lezcano wrote: > > > > > > If we pass the reason to the exit_code of the init process, that will be > > > a bit weird as the process is signaled and did not exited no ? > > > > Just in case, you shouldn't change ->exit_code blindly. We should only > > change it if init was a) SIGKILL'ed and b) pid_ns->reboot_cmd is set. > > In this case we can assume that it was killed by sys_reboot. > > > > Now. I didn't really mean exit_state should be equal to sys_reboot's > > cmd arg. I thought about something like > > > > swicth (reboot_cmd) { > > case LINUX_REBOOT_CMD_RESTART: > > code = SIGHUP; > > break; > > case LINUX_REBOOT_CMD_HALT: > > code = SIGINT; // doesn't really matter what we report > > ... > > } > > Isn't it possible to add the two cases to si_code possible values, e.g. > CDL_RESTART, CDL_HALT (or CDL_SYS_RESTART, CDL_SYS_HALT How? You should change do_wait() paths then. Even if we could, personally I'd strongly object ;) Look, you have the very specific problem. The kernel can't do everything to make everyone happy. There is tradeoff. But if you really meant siginfo->si_code, I do not understand at all what you actually mean. This info is not preserved when the task exits. > to avoid possible > confusion with CDL_STOPPED)? How it is possible to confuse this with CDL_STOPPED? > Then on sys_reboot() flag container init and kill it (this way sys_reboot() > preserves its "will not return on success for restart/halt" scematic)? This is what I suggested... > Then container init would see CLD_KILLED replaced with matching reboot > reason. For what? its parent need this info, not container init. I guess I got lost completely. > Playing with the exit code is probably more problematic OK, then please do something else. I do not pretend I really understand what do you really need to solve your problem. But please do not forget the kernel is already very complex and full of misc hacks ;) > > And, iiuc, the point was to "fix" sys_reboot() so that we do not need > > to mofify the distro/userspace? > > That's definitely the goal (not modify distro/userspace running inside > container). In this case I do not understand how prctl() can help. But please do not try to convince me, this is simply unnecessary ;) Oleg.