From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756098Ab0CVT5k (ORCPT ); Mon, 22 Mar 2010 15:57:40 -0400 Received: from e7.ny.us.ibm.com ([32.97.182.137]:53999 "EHLO e7.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755966Ab0CVT5i (ORCPT ); Mon, 22 Mar 2010 15:57:38 -0400 Date: Mon, 22 Mar 2010 12:57:35 -0700 From: Matt Helsley To: "Serge E. Hallyn" Cc: Louis Rilling , Linux Containers , lkml Subject: Re: [PATCH linux-cr] nested pid namespaces (v2) Message-ID: <20100322195735.GE20796@count0.beaverton.ibm.com> References: <20100319213955.GA17912@us.ibm.com> <20100322105502.GB5569@localdomain> <20100322143800.GD3744@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100322143800.GD3744@us.ibm.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 22, 2010 at 09:38:00AM -0500, Serge E. Hallyn wrote: > Quoting Louis Rilling (Louis.Rilling@kerlabs.com): > > On Fri, Mar 19, 2010 at 04:39:55PM -0500, Serge E. Hallyn wrote: > > > Support checkpoint and restart of tasks in nested pid namespaces. At > > It would probably be safer too to use task_active_pid_ns() instead of > > task->nsproxy->pid_ns, just in case some PID namespace unsharing like proposed > > by Eric makes it to mainline. > > The task is frozen though so it shouldn't be able to unshare while being > checkpointed, right? But it's probably better code anyway. By the time it reaches checkpoint a frozen task is in the refrigerator -- most often in the signal delivery portion of syscall return. So it can't be making any new unshare/setns syscalls and any changes to the namespaces should be visible. Cheers, -Matt Helsley