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vhost_net: add missing lock nesting notation

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[ Upstream commit aaa3149bbe ]

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: 0308813724 ("vhost_net: basic polling support")
Reported-by: syzbot+7f073540b1384a614e09@syzkaller.appspotmail.com
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jason Wang 2018-03-26 16:10:23 +08:00 committed by Greg Kroah-Hartman
parent 8c316b6257
commit 9fdeb33e19
1 changed files with 2 additions and 2 deletions
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4
drivers/vhost/net.c
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@ -622,7 +622,7 @@ 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();
@ -755,7 +755,7 @@ 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;