From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758173Ab2HHMxi (ORCPT ); Wed, 8 Aug 2012 08:53:38 -0400 Received: from relay.parallels.com ([195.214.232.42]:40849 "EHLO relay.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753563Ab2HHMxg (ORCPT ); Wed, 8 Aug 2012 08:53:36 -0400 Message-ID: <50226147.3010309@parallels.com> Date: Wed, 8 Aug 2012 16:53:27 +0400 From: Stanislav Kinsbursky User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120714 Thunderbird/14.0 MIME-Version: 1.0 To: "davem@davemloft.net" CC: "netdev@vger.kernel.org" , "ruanzhijie@hotmail.com" , "linux-kernel@vger.kernel.org" , "viro@zeniv.linux.org.uk" Subject: Re: [RFC PATCH] tun: don't zeroize sock->file on detach References: <20120711114753.24395.53193.stgit@localhost6.localdomain6> In-Reply-To: <20120711114753.24395.53193.stgit@localhost6.localdomain6> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Dave. What about this patch? On Wed, Jul 11, 2012 at 03:48:20PM +0400, Stanislav Kinsbursky wrote: > This is a fix for bug, introduced in 3.4 kernel by commit > 1ab5ecb90cb6a3df1476e052f76a6e8f6511cb3d, which, among other things, replaced > simple sock_put() by sk_release_kernel(). Below is sequence, which leads to > oops for non-persistent devices: > > tun_chr_close() > tun_detach() <== tun->socket.file = NULL > tun_free_netdev() > sk_release_sock() > sock_release(sock->file == NULL) > iput(SOCK_INODE(sock)) <== dereference on NULL pointer > > This patch just removes zeroing of socket's file from __tun_detach(). > sock_release() will do this. > > Signed-off-by: Stanislav Kinsbursky > --- > drivers/net/tun.c | 1 - > 1 files changed, 0 insertions(+), 1 deletions(-) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index 987aeef..c1639f3 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -185,7 +185,6 @@ static void __tun_detach(struct tun_struct *tun) > netif_tx_lock_bh(tun->dev); > netif_carrier_off(tun->dev); > tun->tfile = NULL; > - tun->socket.file = NULL; > netif_tx_unlock_bh(tun->dev);