Commit b1be2cfc authored Aug 09, 2023 by Jason Wang Committed by Greg Kroah-Hartman Aug 30, 2023

virtio-net: set queues after driver_ok



commit 51b813176f098ff61bd2833f627f5319ead098a5 upstream.

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().

Note that rtnl needs to be held for userspace requests to change the
number of queues. So we are serialized in this way.

Fixes: 25266128fe16 ("virtio-net: fix race between set queues and probe")
Reported-by: Dragos Tatulea <dtatulea@nvidia.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 4821df2f

drivers/net/virtio_net.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -3265,8 +3265,6 @@ static int virtnet_probe(struct virtio_device *vdev)
		}
		}

		_virtnet_set_queues(vi, vi->curr_queue_pairs);

		/* serialize netdev register + virtio_device_ready() with ndo_open() */
		rtnl_lock();

		@@ -3279,6 +3277,8 @@ static int virtnet_probe(struct virtio_device *vdev)

		virtio_device_ready(vdev);

		_virtnet_set_queues(vi, vi->curr_queue_pairs);

		rtnl_unlock();

		err = virtnet_cpu_notif_add(vi);