On Tue, 2023-08-08 at 23:13 -0400, Jason Wang wrote:
> Commit 25266128fe16 ("virtio-net: fix race between set queues and
> probe") tries to fix the race between set queues and probe by calling
> _virtnet_set_queues() before DRIVER_OK is set. This violates virtio
> spec. Fixing this by setting queues after virtio_device_ready().
>
> Fixes: 25266128fe16 ("virtio-net: fix race between set queues and probe")
> Reported-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> The patch is needed for -stable.
> ---
> drivers/net/virtio_net.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 1270c8d23463..ff03921e46df 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -4219,8 +4219,6 @@ static int virtnet_probe(struct virtio_device *vdev)
> if (vi->has_rss || vi->has_rss_hash_report)
> virtnet_init_default_rss(vi);
>
> - _virtnet_set_queues(vi, vi->curr_queue_pairs);
> -
> /* serialize netdev register + virtio_device_ready() with ndo_open()
> */
> rtnl_lock();
>
> @@ -4233,6 +4231,8 @@ static int virtnet_probe(struct virtio_device *vdev)
>
> virtio_device_ready(vdev);
>
> + _virtnet_set_queues(vi, vi->curr_queue_pairs);
> +
> /* a random MAC address has been assigned, notify the device.
> * We don't fail probe if VIRTIO_NET_F_CTRL_MAC_ADDR is not there
> * because many devices work fine without getting MAC explicitly
Thanks for the quick fix. Doesn't this fix though bring back the original race
that was fixed in commit 25266128fe16 ("virtio-net: fix race between set queues
and probe")? Or is being under the same rntl_lock session as register_netdev
enough to avoid the race?
Thanks,
Dragos
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