Re: [PATCH net-next V6 4/4] virtio-net: synchronize probe with ndo_set_features

[Jason Wang]

On Tue, Aug 6, 2024 at 8:25 PM Michael S. Tsirkin <mst@xxxxxxxxxx> wrote:
>
> On Tue, Aug 06, 2024 at 10:22:24AM +0800, Jason Wang wrote:
> > We calculate guest offloads during probe without the protection of
> > rtnl_lock. This lead to race between probe and ndo_set_features. Fix
> > this by moving the calculation under the rtnl_lock.
> >
> > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
>
> Fixes tag pls?

Fixes: 3f93522ffab2 ("virtio-net: switch off offloads on demand if
possible on XDP set")

Thanks


>
> > ---
> >  drivers/net/virtio_net.c | 10 +++++-----
> >  1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > index fc5196ca8d51..1d86aa07c871 100644
> > --- a/drivers/net/virtio_net.c
> > +++ b/drivers/net/virtio_net.c
> > @@ -6596,6 +6596,11 @@ static int virtnet_probe(struct virtio_device *vdev)
> >               netif_carrier_on(dev);
> >       }
> >
> > +     for (i = 0; i < ARRAY_SIZE(guest_offloads); i++)
> > +             if (virtio_has_feature(vi->vdev, guest_offloads[i]))
> > +                     set_bit(guest_offloads[i], &vi->guest_offloads);
> > +     vi->guest_offloads_capable = vi->guest_offloads;
> > +
> >       rtnl_unlock();
> >
> >       err = virtnet_cpu_notif_add(vi);
> > @@ -6604,11 +6609,6 @@ static int virtnet_probe(struct virtio_device *vdev)
> >               goto free_unregister_netdev;
> >       }
> >
> > -     for (i = 0; i < ARRAY_SIZE(guest_offloads); i++)
> > -             if (virtio_has_feature(vi->vdev, guest_offloads[i]))
> > -                     set_bit(guest_offloads[i], &vi->guest_offloads);
> > -     vi->guest_offloads_capable = vi->guest_offloads;
> > -
> >       pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
> >                dev->name, max_queue_pairs);
> >
> > --
> > 2.31.1
>