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From: David Rientjes <rientjes@google.com>
To: Lukasz Pawelczyk <l.pawelczyk@samsung.com>
Cc: Lukasz Pawelczyk <havner@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>, Michal Hocko <mhocko@suse.cz>,
	Sameer Nanda <snanda@chromium.org>,
	Guillaume Morin <guillaume@morinfr.org>,
	Li Zefan <lizefan@huawei.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] kernel/exit.c: make sure current's nsproxy != NULL while checking caps
Date: Mon, 1 Dec 2014 13:08:46 -0800 (PST)	[thread overview]
Message-ID: <alpine.DEB.2.10.1412011307450.16984@chino.kir.corp.google.com> (raw)
In-Reply-To: <1417086070.1805.9.camel@samsung.com>

[-- Attachment #1: Type: TEXT/PLAIN, Size: 1588 bytes --]

On Thu, 27 Nov 2014, Lukasz Pawelczyk wrote:

> On śro, 2014-11-26 at 13:32 -0800, David Rientjes wrote:
> > On Wed, 26 Nov 2014, Lukasz Pawelczyk wrote:
> > > 
> > > LSM task_kill() hook is triggered and current->nsproxy within is NULL.
> > > 
> > > This happens during an exit() syscall because exit_task_namespaces() is
> > > called before the exit_notify(). This patch changes their order.
> > > 
> > 
> > This is a classic case of a patch being proposed for a problem that only 
> > occurs on kernels that include other patches that are not upstream.  The 
> > order that things are deconstructed in the exit path is complex and 
> > carefully choreographed, changing it comes at significant risk.  That risk 
> > would be justified if a patch were being proposed for upstream that fixes 
> > an upstream problem.  It becomes too much of a maintenance nightmare to 
> > try to address problems and keep issues from arising for non-upstream 
> > patches.  Thus, I don't think this is something that we want.
> 
> This is a problem for the change I'm working on and I will be
> upstreaming it too at some point. Please see my other reply for more
> details:
> 
> http://www.spinics.net/lists/kernel/msg1877152.html
> 
> The only thing I can do then is to post this patch together with the
> other patches when the time comes. But since this issue is rather
> separate I've decided to try to push it earlier.
> 

Yeah, it would be best to fold this into a series that needs 
current->nsproxy to be valid at a sequence point in the exit path as part 
of the same patch that requires it.

      reply	other threads:[~2014-12-01 21:08 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-26 14:21 [PATCH] kernel/exit.c: make sure current's nsproxy != NULL while checking caps Lukasz Pawelczyk
2014-11-26 20:52 ` Oleg Nesterov
2014-11-27 10:55   ` Lukasz Pawelczyk
2014-11-26 21:32 ` David Rientjes
2014-11-27 11:01   ` Lukasz Pawelczyk
2014-12-01 21:08     ` David Rientjes [this message]

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