From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751750AbeCZIKc (ORCPT ); Mon, 26 Mar 2018 04:10:32 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:56672 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750864AbeCZIKa (ORCPT ); Mon, 26 Mar 2018 04:10:30 -0400 From: Jason Wang To: mst@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Jason Wang Subject: [PATCH net] vhost_net: add missing lock nesting notation Date: Mon, 26 Mar 2018 16:10:23 +0800 Message-Id: <1522051823-5166-1-git-send-email-jasowang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We try to hold TX virtqueue mutex in vhost_net_rx_peek_head_len() after RX virtqueue mutex is held in handle_rx(). This requires an appropriate lock nesting notation to calm down deadlock detector. Fixes: 0308813724606 ("vhost_net: basic polling support") Reported-by: syzbot+7f073540b1384a614e09@syzkaller.appspotmail.com Signed-off-by: Jason Wang --- drivers/vhost/net.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 8139bc7..12bcfba 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -630,7 +630,7 @@ static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk) if (!len && vq->busyloop_timeout) { /* Both tx vq and rx socket were polled here */ - mutex_lock(&vq->mutex); + mutex_lock_nested(&vq->mutex, 1); vhost_disable_notify(&net->dev, vq); preempt_disable(); @@ -763,7 +763,7 @@ static void handle_rx(struct vhost_net *net) struct iov_iter fixup; __virtio16 num_buffers; - mutex_lock(&vq->mutex); + mutex_lock_nested(&vq->mutex, 0); sock = vq->private_data; if (!sock) goto out; -- 2.7.4