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 at syzkaller.appspotmail.com
Signed-off-by: Jason Wang <jasowang at redhat.com>
---
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
Michael S. Tsirkin
2018-Mar-26 13:24 UTC
[PATCH net] vhost_net: add missing lock nesting notation
On Mon, Mar 26, 2018 at 04:10:23PM +0800, Jason Wang wrote:> 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 at syzkaller.appspotmail.com > Signed-off-by: Jason Wang <jasowang at redhat.com>Acked-by: Michael S. Tsirkin <mst at redhat.com>> --- > 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
David Miller
2018-Mar-26 16:59 UTC
[PATCH net] vhost_net: add missing lock nesting notation
From: Jason Wang <jasowang at redhat.com> Date: Mon, 26 Mar 2018 16:10:23 +0800> 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 at syzkaller.appspotmail.com > Signed-off-by: Jason Wang <jasowang at redhat.com>Applied and queued up for -stable, thanks Jason.