From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: [PATCH net V2] vhost: correctly remove wait queue during poll failure Date: Tue, 27 Mar 2018 20:50:52 +0800 Message-ID: <1522155052-13347-1-git-send-email-jasowang__19225.2996880145$1522154943$gmane$org@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: mst@redhat.com, jasowang@redhat.com Cc: netdev@vger.kernel.org, Darren Kenny , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org 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 --- 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