From mboxrd@z Thu Jan  1 00:00:00 1970
From: Oleg Nesterov <oleg-6lXkIZvqkOAvJsYlp49lxw@public.gmane.org>
Subject: Re: [PATCH 4/9] pid: Generalize task_active_pid_ns
Date: Thu, 13 Dec 2007 19:01:28 +0300
Message-ID: <20071213160128.GA219@tv-sign.ru>
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To: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
Cc: Linux Containers <containers-qjLDD68F18O7TbgM5vRIOg@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>
List-Id: containers.vger.kernel.org

Sorry for the delay, and sorry, can't read this series carefully now.
A couple of question though.

On 12/12, Eric W. Biederman wrote:
>
> Currently task_active_pid_ns is not safe to call after a
> task becomes a zombie and exit_task_namespaces is called,
> as nsproxy becomes NULL.  By reading the pid namespace from
> the pid of the task we can trivially solve this problem

Confused. If the task becomes a zombie, we can't assume it has a valid
->pids[].pid. The parent can release us as soon as exit_notify() drops
tasklist.

?

Oleg.