From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:40868 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935257AbeDKTGj (ORCPT ); Wed, 11 Apr 2018 15:06:39 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+7f073540b1384a614e09@syzkaller.appspotmail.com, Jason Wang , "Michael S. Tsirkin" , "David S. Miller" Subject: [PATCH 4.9 306/310] vhost_net: add missing lock nesting notation Date: Wed, 11 Apr 2018 20:37:25 +0200 Message-Id: <20180411183635.706806905@linuxfoundation.org> In-Reply-To: <20180411183622.305902791@linuxfoundation.org> References: <20180411183622.305902791@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Wang [ Upstream commit aaa3149bbee9ba9b4e6f0bd6e3e7d191edeae942 ] 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 Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/vhost/net.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -524,7 +524,7 @@ static int vhost_net_rx_peek_head_len(st 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(); @@ -657,7 +657,7 @@ static void handle_rx(struct vhost_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;