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From: Cedric Le Goater <clg@fr.ibm.com>
To: "Serge E. Hallyn" <serue@us.ibm.com>
Cc: linux-kernel@vger.kernel.org,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Oleg Nesterov <oleg@tv-sign.ru>,
	Daniel Hokka Zakrisson <daniel@hozac.com>,
	herbert@13thfloor.at, akpm@osdl.org, trond.myklebust@fys.uio.no,
	Linux Containers <containers@lists.osdl.org>
Subject: Re: [PATCH] namespaces: fix race at task exit
Date: Thu, 25 Jan 2007 16:20:23 +0100	[thread overview]
Message-ID: <45B8CAB7.9050402@fr.ibm.com> (raw)
In-Reply-To: <20070125150542.GA27472@sergelap.austin.ibm.com>

Serge E. Hallyn wrote:
> In do_exit(), the exit_task_namespaces() was placed after
> exit_notify() because exit_notify ends up using the pid
> namespace both to access the reaper, and for detaching the
> pid.  However, this placement allows an nfs server to reap
> the task before exit_task_namespaces() completes.
> 
> This patch moves the exit_task_namespaces() into release_task,
> below release_thread() which puts the pids(), and just above
> the call_rcu(delayed_put_task_struct).  I believe this should
> solve both problems.
> 
> Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>

I've run some tests on x86 and x86_64: mounted a NFS share after 
having unshare(CLONE_NEWNS) and I didn't reproduce the bug Daniel 
had found. 

it looks safe.

C.
 


  reply	other threads:[~2007-01-25 15:20 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-25 15:05 Serge E. Hallyn
2007-01-25 15:20 ` Cedric Le Goater [this message]
2007-01-25 16:29 ` Eric W. Biederman
2007-01-25 17:35   ` Serge E. Hallyn
2007-01-25 20:36     ` Serge E. Hallyn
2007-01-25 16:39 ` Oleg Nesterov
2007-01-25 17:36   ` Serge E. Hallyn

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