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From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman)
To: Gao feng <gaofeng-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
Cc: Linux Containers
	<containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Andrew Morton
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	Oleg Nesterov <oleg-6lXkIZvqkOAvJsYlp49lxw@public.gmane.org>
Subject: Re: [PATCH 09/11] pidns: Add setns support
Date: Mon, 19 Nov 2012 01:27:41 -0800	[thread overview]
Message-ID: <87wqxij62a.fsf@xmission.com> (raw)
In-Reply-To: <50A9F7DE.60807-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org> (Gao feng's message of "Mon, 19 Nov 2012 17:11:58 +0800")

Gao feng <gaofeng@cn.fujitsu.com> writes:

> 于 2012年11月17日 00:35, Eric W. Biederman 写道:
>> From: "Eric W. Biederman" <ebiederm@xmission.com>
>> 
>> - Pid namespaces are designed to be inescapable so verify that the
>>   passed in pid namespace is a child of the currently active
>>   pid namespace or the currently active pid namespace itself.
>> 
>>   Allowing the currently active pid namespace is important so
>>   the effects of an earlier setns can be cancelled.
>> 
>> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
>> ---
>
> Hi Eric
>
> I noticed that,after we call setns to change task's pidns to container A's pidns.
> we can't see this task in container A's proc filesystem.
>
> Is this what we expected?

Only children move to the new pid namespace so yes.

Any other semantic requires ugly races with changing the pid of an
existing process.

Eric

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  parent reply	other threads:[~2012-11-19  9:27 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-16 16:32 [REVIEW][PATCH 0/11] pid namespace cleanups and enhancements Eric W. Biederman
     [not found] ` <8739097bkk.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-11-16 16:35   ` [PATCH 01/11] procfs: Use the proc generic infrastructure for proc/self Eric W. Biederman
     [not found]     ` <1353083750-3621-1-git-send-email-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-11-16 16:35       ` [PATCH 02/11] procfs: Don't cache a pid in the root inode Eric W. Biederman
     [not found]         ` <1353083750-3621-2-git-send-email-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-11-21  1:07           ` Gao feng
2012-11-16 16:35       ` [PATCH 03/11] pidns: Capture the user namespace and filter ns_last_pid Eric W. Biederman
     [not found]         ` <1353083750-3621-3-git-send-email-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-11-21  1:26           ` Gao feng
2012-11-16 16:35       ` [PATCH 04/11] pidns: Use task_active_pid_ns where appropriate Eric W. Biederman
     [not found]         ` <1353083750-3621-4-git-send-email-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-11-21  2:02           ` Gao feng
2012-11-16 16:35       ` [PATCH 05/11] pidns: Make the pidns proc mount/umount logic obvious Eric W. Biederman
     [not found]         ` <1353083750-3621-5-git-send-email-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-11-19 11:02           ` Gao feng
2012-11-16 16:35       ` [PATCH 06/11] pidns: Don't allow new processes in a dead pid namespace Eric W. Biederman
     [not found]         ` <1353083750-3621-6-git-send-email-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-11-21  2:17           ` Gao feng
2012-11-16 16:35       ` [PATCH 07/11] pidns: Wait in zap_pid_ns_processes until pid_ns->nr_hashed == 1 Eric W. Biederman
2012-11-16 16:35       ` [PATCH 08/11] pidns: Deny strange cases when creating pid namespaces Eric W. Biederman
     [not found]         ` <1353083750-3621-8-git-send-email-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-11-21  2:25           ` Gao feng
2012-11-16 16:35       ` [PATCH 09/11] pidns: Add setns support Eric W. Biederman
     [not found]         ` <1353083750-3621-9-git-send-email-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-11-19  9:11           ` Gao feng
     [not found]             ` <50A9F7DE.60807-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2012-11-19  9:27               ` Eric W. Biederman [this message]
2012-11-21  2:36           ` Gao feng
2012-11-16 16:35       ` [PATCH 10/11] pidns: Consolidate initialzation of special init task state Eric W. Biederman
     [not found]         ` <1353083750-3621-10-git-send-email-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-11-21  2:56           ` Gao feng
2012-11-16 16:35       ` [PATCH 11/11] pidns: Support unsharing the pid namespace Eric W. Biederman
     [not found]         ` <1353083750-3621-11-git-send-email-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-11-21  2:55           ` Gao feng
2012-12-19 18:14           ` Oleg Nesterov
     [not found]             ` <20121219181400.GA22991-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-12-21  1:43               ` Eric W. Biederman
     [not found]                 ` <871uektc2f.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-12-21 15:49                   ` Oleg Nesterov
     [not found]                     ` <20121221154931.GA18730-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-12-21 17:51                       ` Eric W. Biederman
     [not found]                         ` <87fw2zmgzc.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-12-21 19:24                           ` Rob Landley
2012-12-21 22:58                             ` namespace documentation Eric W. Biederman
     [not found]     ` <1353083750-3621-7-git-send-email-ebiederm@xmission.com>
     [not found]       ` <1353083750-3621-7-git-send-email-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-11-21  2:24         ` [PATCH 07/11] pidns: Wait in zap_pid_ns_processes until pid_ns->nr_hashed == 1 Gao feng
2012-12-19 18:47         ` Oleg Nesterov
     [not found]           ` <20121219184757.GB22991-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-12-21  1:19             ` Eric W. Biederman
     [not found]               ` <87bodourqt.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-12-21 14:11                 ` Oleg Nesterov
     [not found]                   ` <20121221141133.GA13805-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-12-21 15:02                     ` Oleg Nesterov
     [not found]                       ` <20121221150238.GA16003-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-12-21 15:31                         ` Oleg Nesterov
     [not found]                           ` <20121221153152.GA17250-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-12-21 18:42                             ` Eric W. Biederman
2012-12-21 18:33                     ` Eric W. Biederman

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