From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752503AbeC0NHR (ORCPT ); Tue, 27 Mar 2018 09:07:17 -0400 Received: from aserp2130.oracle.com ([141.146.126.79]:55380 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752120AbeC0NHP (ORCPT ); Tue, 27 Mar 2018 09:07:15 -0400 Date: Tue, 27 Mar 2018 14:07:03 +0100 From: Darren Kenny To: Jason Wang Cc: mst@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net V2] vhost: correctly remove wait queue during poll failure Message-ID: <20180327130703.g5h2npkp2bnvvebg@dhcp-10-175-199-170.vpn.oracle.com> Mail-Followup-To: Jason Wang , mst@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <1522155052-13347-1-git-send-email-jasowang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline In-Reply-To: <1522155052-13347-1-git-send-email-jasowang@redhat.com> User-Agent: NeoMutt/20180223 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8844 signatures=668695 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=11 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1711220000 definitions=main-1803270133 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 27, 2018 at 08:50:52PM +0800, Jason Wang wrote: >We tried to remove vq poll from wait queue, but do not check whether >or not it was in a list before. This will lead double free. Fixing >this by switching to use vhost_poll_stop() which zeros poll->wqh after >removing poll from waitqueue to make sure it won't be freed twice. > >Cc: Darren Kenny >Reported-by: syzbot+c0272972b01b872e604a@syzkaller.appspotmail.com >Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend") >Signed-off-by: Jason Wang Reviewed-by: Darren Kenny >--- >Changes from V1: >- tweak the commit log for to match the code >--- > drivers/vhost/vhost.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > >diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c >index 1b3e8d2d..5d5a9d9 100644 >--- a/drivers/vhost/vhost.c >+++ b/drivers/vhost/vhost.c >@@ -212,8 +212,7 @@ int vhost_poll_start(struct vhost_poll *poll, struct file *file) > if (mask) > vhost_poll_wakeup(&poll->wait, 0, 0, poll_to_key(mask)); > if (mask & EPOLLERR) { >- if (poll->wqh) >- remove_wait_queue(poll->wqh, &poll->wait); >+ vhost_poll_stop(poll); > ret = -EINVAL; > } > >-- >2.7.4 >