Return-Path: <linux-kernel-owner+w=401wt.eu-S932630AbXAQS6q@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S932630AbXAQS6q (ORCPT <rfc822;w@1wt.eu>);
	Wed, 17 Jan 2007 13:58:46 -0500
Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932636AbXAQS6q
	(ORCPT <rfc822;linux-kernel-outgoing>);
	Wed, 17 Jan 2007 13:58:46 -0500
Received: from mail.screens.ru ([213.234.233.54]:57562 "EHLO mail.screens.ru"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S932630AbXAQS6p (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Wed, 17 Jan 2007 13:58:45 -0500
Date: Wed, 17 Jan 2007 21:58:23 +0300
From: Oleg Nesterov <oleg@tv-sign.ru>
To: Daniel Hokka Zakrisson <daniel@hozac.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>, linux-kernel@vger.kernel.org,
       herbert@13thfloor.at, akpm@osdl.org, trond.myklebust@fys.uio.no,
       Linux Containers <containers@lists.osdl.org>
Subject: Re: NFS causing oops when freeing namespace
Message-ID: <20070117185823.GA878@tv-sign.ru>
References: <57238.192.168.101.6.1169029688.squirrel@intranet> <m18xg1akmd.fsf@ebiederm.dsl.xmission.com> <51072.192.168.101.6.1169039633.squirrel@intranet>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <51072.192.168.101.6.1169039633.squirrel@intranet>
User-Agent: Mutt/1.5.11
Sender: linux-kernel-owner@vger.kernel.org
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 1340
Lines: 40

On 01/17, Daniel Hokka Zakrisson wrote:
>
> >> Call Trace:
> >>  [<c03be6f0>] _spin_lock_irqsave+0x20/0x90
> >>  [<c01f6115>] lockd_down+0x125/0x190
> >>  [<c01d26bd>] nfs_free_server+0x6d/0xd0
> >>  [<c01d8e9c>] nfs_kill_super+0xc/0x20
> >>  [<c0161c5d>] deactivate_super+0x7d/0xa0
> >>  [<c0175e0e>] release_mounts+0x6e/0x80
> >>  [<c0175e86>] __put_mnt_ns+0x66/0x80
> >>  [<c0132b3e>] free_nsproxy+0x5e/0x60
> >>  [<c011f021>] do_exit+0x791/0x810
> >>  [<c011f0c6>] do_group_exit+0x26/0x70
> >>  [<c0103142>] sysenter_past_esp+0x5f/0x85
> >>  [<c03b0033>] rpc_wake_up+0x3/0x70
>
> It was the only semi-plausible explanation I could come up with. I added a
> printk in do_exit right before exit_task_namespaces, where sighand was
> still set, and one right before the spin_lock_irq in lockd_down, where it
> had suddenly been set to NULL.

I can't reproduce the problem, but

	do_exit:
		exit_notify(tsk);
		exit_task_namespaces(tsk);

the task could be reaped by its parent in between.

We should not use ->signal/->sighand after exit_notify().

Can we move exit_task_namespaces() up?

Oleg.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/