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Commit 1d877327 authored by Jason Wang's avatar Jason Wang Committed by Greg Kroah-Hartman
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virtio-net: fix race between ndo_open() and virtio_device_ready() 



commit 50c0ada627f56c92f5953a8bf9158b045ad026a1 upstream.

We currently call virtio_device_ready() after netdev
registration. Since ndo_open() can be called immediately
after register_netdev, this means there exists a race between
ndo_open() and virtio_device_ready(): the driver may start to use the
device before DRIVER_OK which violates the spec.

Fix this by switching to use register_netdevice() and protect the
virtio_device_ready() with rtnl_lock() to make sure ndo_open() can
only be called after virtio_device_ready().

Fixes: 4baf1e33 ("virtio_net: enable VQs early")
Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Message-Id: <20220617072949.30734-1-jasowang@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7f89bb5d

drivers/net/virtio_net.c

+7 −1
Original line number Diff line number Diff line
@@ -3219,14 +3219,20 @@ static int virtnet_probe(struct virtio_device *vdev) 
		}

	}



	err = register_netdev(dev);

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

	rtnl_lock();



	err = register_netdevice(dev);

	if (err) {

		pr_debug("virtio_net: registering device failed\n");

		rtnl_unlock();

		goto free_failover;

	}



	virtio_device_ready(vdev);



	rtnl_unlock();



	err = virtnet_cpu_notif_add(vi);

	if (err) {

		pr_debug("virtio_net: registering cpu notifier failed\n");