Re: [PATCH net] vhost_net: don't continue to call the recvmsg when meet errors
From: Michael S. Tsirkin
Date: Wed Nov 30 2016 - 08:44:04 EST
On Wed, Nov 30, 2016 at 09:07:16PM +0800, Jason Wang wrote:
> On 2016å11æ30æ 20:10, Yunjian Wang wrote:
> > When we meet an error(err=-EBADFD) recvmsg, the error handling in vhost
> > handle_rx() will continue. This will cause a soft CPU lockup in vhost thread.
> > Signed-off-by: Yunjian Wang <wangyunjian@xxxxxxxxxx>
> > ---
> > drivers/vhost/net.c | 3 +++
> > 1 file changed, 3 insertions(+)
> > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> > index 5dc128a..edc470b 100644
> > --- a/drivers/vhost/net.c
> > +++ b/drivers/vhost/net.c
> > @@ -717,6 +717,9 @@ static void handle_rx(struct vhost_net *net)
> > pr_debug("Discarded rx packet: "
> > " len %d, expected %zd\n", err, sock_len);
> > vhost_discard_vq_desc(vq, headcount);
> > + /* Don't continue to do, when meet errors. */
> > + if (err < 0)
> > + goto out;
> > continue;
> > }
> > /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */
> Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
> We may want to rename vhost_discard_vq_desc() in the future, since it does
> not discard the desc in fact.
To me this looks a bit too aggressive. I would also like commit log
to explain better what is going on, to make sure we are
not just treating the symptoms.