Return-Path: linux-nfs-owner@vger.kernel.org
Received: from out2-smtp.messagingengine.com ([66.111.4.26]:33560 "EHLO
	out2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK)
	by vger.kernel.org with ESMTP id S1754654Ab3LFScr (ORCPT
	<rfc822;linux-nfs@vger.kernel.org>); Fri, 6 Dec 2013 13:32:47 -0500
Date: Fri, 6 Dec 2013 10:32:45 -0800
From: Greg KH <greg@kroah.com>
To: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Weng Meiling <wengmeiling.weng@huawei.com>, stable@vger.kernel.org,
        skinsbursky@parallels.com, linux-nfs@vger.kernel.org,
        lizefan@huawei.com, h.huangqiang@huawei.com
Subject: Re: [PATCH 3.4 9/9] nfsd: use the current net ns in write_threads()
 and write_ports()
Message-ID: <20131206183245.GB4379@kroah.com>
References: <1386136415-30976-1-git-send-email-wengmeiling.weng@huawei.com>
 <1386136415-30976-10-git-send-email-wengmeiling.weng@huawei.com>
 <20131204212532.GB19452@fieldses.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
In-Reply-To: <20131204212532.GB19452@fieldses.org>
Sender: linux-nfs-owner@vger.kernel.org
List-ID: <linux-nfs.vger.kernel.org>

On Wed, Dec 04, 2013 at 04:25:33PM -0500, J. Bruce Fields wrote:
> On Wed, Dec 04, 2013 at 01:53:35PM +0800, Weng Meiling wrote:
> > Upstream commit f7fb86c6e639360ad9c253cec534819ef928a674 (nfsd: use
> > "init_net" for portmapper) introduced a bug.
> > 
> > Starting NFSd in a non init_net network namespace will lead to
> > NULL pointer deference. Because RPCBIND client will be NULL when register
> > RPC service with the local portmapper in svc_addsock().
> > 
> > BUG: unable to handle kernel NULL pointer dereference at 0000000000000060
> > IP: [<ffffffffa0439150>] call_start+0x10/0x30 [sunrpc]
> > ...
> > Pid: 27770, comm: rpc.nfsd ...
> > RIP: 0010:[<ffffffffa0439150>]  [<ffffffffa0439150>] call_start+0x10/0x30 [sunrpc]
> > ...
> >   [<ffffffffa0442841>] __rpc_execute+0x91/0x160 [sunrpc]
> >   [<ffffffffa0442981>] rpc_execute+0x71/0x80 [sunrpc]
> >   [<ffffffffa043ab49>] rpc_run_task+0x89/0xa0 [sunrpc]
> >   [<ffffffffa043ac5d>] rpc_call_sync+0x3d/0x70 [sunrpc]
> >   [<ffffffffa044b316>] rpcb_register+0xa6/0xd0 [sunrpc]
> >   [<ffffffffa0444ede>] __svc_register+0x1ae/0x1c0 [sunrpc]
> >   [<ffffffff8114f975>] ? cache_alloc_refill+0x85/0x290
> >   [<ffffffffa0444f7f>] svc_register+0x8f/0xc0 [sunrpc]
> >   [<ffffffff811504f3>] ? kmem_cache_alloc_trace+0xc3/0x1d0
> >   [<ffffffffa04472f8>] svc_setup_socket+0x1a8/0x2c0 [sunrpc]
> >   [<ffffffff81009546>] ? read_tsc+0x16/0x40
> >   [<ffffffffa0448078>] svc_addsock+0x118/0x1c0 [sunrpc]
> >   [<ffffffff81090ee5>] ? do_gettimeofday+0x15/0x50
> >   [<ffffffffa049e69c>] ? nfsd_create_serv+0xdc/0x150 [nfsd]
> >   [<ffffffff8125605c>] ? simple_strtoull+0x2c/0x50
> >   [<ffffffffa049fdce>] __write_ports+0x1fe/0x230 [nfsd]
> >   [<ffffffffa049fe37>] write_ports+0x37/0x60 [nfsd]
> >   [<ffffffffa049fe00>] ? __write_ports+0x230/0x230 [nfsd]
> >   [<ffffffffa049edd2>] nfsctl_transaction_write+0x72/0x90 [nfsd]
> >   [<ffffffff8116573b>] vfs_write+0xcb/0x130
> >   [<ffffffff81165890>] sys_write+0x50/0x90
> > 
> > Fix it by using the current's network namespace so NFSd uses the
> > consistent net ns all the time.
> 
> Everything else looks like a straightforward backport, but doing this
> differently from upstream makes me nervous.  Don't we also want to take
> 11f779421a39b86da8a523d97e5fd3477878d44f "nfsd: containerize NFSd
> filesystem" ?  (Stanislav?)

I'd prefer not doing it differently from upstream as well.

thanks,

greg k-h