From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755406Ab2LRVxz (ORCPT ); Tue, 18 Dec 2012 16:53:55 -0500 Received: from charlotte.tuxdriver.com ([70.61.120.58]:56216 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754569Ab2LRVxw (ORCPT ); Tue, 18 Dec 2012 16:53:52 -0500 Date: Tue, 18 Dec 2012 16:53:16 -0500 From: Neil Horman To: "Eric W. Biederman" Cc: Oleg Nesterov , Pavel Emelyanov , Daniel Berrange , Alexander Viro , Serge Hallyn , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: + core_pattern-set-core-helpers-root-and-namespace-to-crashing-process .patch added to -mm tree Message-ID: <20121218215316.GA4329@neilslaptop.think-freely.org> References: <20121217123428.GA1957@redhat.com> <20121217150559.GD25322@hmsreliant.think-freely.org> <20121217160408.GA20166@redhat.com> <20121217183925.GE25322@hmsreliant.think-freely.org> <20121218200604.GA28834@redhat.com> <20121218201900.GA10059@hmsreliant.think-freely.org> <874njj3x9d.fsf@xmission.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <874njj3x9d.fsf@xmission.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Spam-Score: -2.9 (--) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 18, 2012 at 12:45:18PM -0800, Eric W. Biederman wrote: > Neil Horman writes: > > > On Tue, Dec 18, 2012 at 09:06:04PM +0100, Oleg Nesterov wrote: > >> On 12/17, Neil Horman wrote: > >> > > >> > On Mon, Dec 17, 2012 at 05:04:08PM +0100, Oleg Nesterov wrote: > >> > > > >> > > > Is there a way to switch all namespaces, except for the pid > >> > > > namespace? > >> > > > >> > > Which exactly namespaces you want to change? > >> > > > >> > Ideally, I want the pipe reader process to execute in the same namespaces that > >> > the crashing process executed in (i.e. the pipe reader should execute as though > >> > the crashing process forked it). > >> > >> Yes, and we probably want to change pid_ns as well. But afaics currently > >> this is not possible, even setns can't do this. > > The code for setns to change the pid namespace just merged. > Can you post a link to the merge commit for reference so I can take a look at it? > Oleg I copied you on that code when I put it up for review. Did I use > the wrong email address? > > >> BTW. Of course this is subjective, but personally I think that "||" > >> looks strange. Perhaps it would be better to add something like > >> --croot argument? > >> > > The || is ambiguous with its simmilarity to a shell 'or' command, but I don't > > think the --croot argument is much better on that front, as that then becomes > > ambiguous with arguments supplied to the pipe reader directly. The token should > > be leading the pipe_reader string in core_pattern to indicate a change in > > environment independent of the executable path. Perhaps |^ or something > > simmilar? > > I failed to send my earlier reply but there is another problem with the > approach of only having one global core dump pattern. You can't set it > per container. Which means a special character to switch namespeces > while a reasonable solution (and arguably unnecessary solution) is not a > complete solution. > > > Either way, Andrew, could you please drop this patch? Olegs comments I think > > make it pretty clear I've got some more work to do on this. > > If we just want one pattern we should be able to to robustly implement > this in userspace with the existing functionality. With the caveat that > we need to get some pid namespace and user namespace bugs in the core > pattern generation fixed. But we need to fix those bugs anyway. > Then perhaps the right thing to do here is in fact just make core_pattern a per-namespace sysctl. I only took a brief look, but I was unable to find an example of such a per-namespace systctl. Do we already have the infrastructure to do such a thing? I didn't think we did. Thanks! Neil > Eric >