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Commit eaaa59ae authored by Jason Wang's avatar Jason Wang Committed by Greg Kroah-Hartman
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caif_virtio: fix race between virtio_device_ready() and ndo_open() 



commit 11a37eb66812ce6a06b79223ad530eb0e1d7294d upstream.

We currently depend on probe() calling virtio_device_ready() -
which happens 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 (e.g. TX) 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: 0d2e1a29 ("caif_virtio: Introduce caif over virtio")
Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Message-Id: <20220620051115.3142-3-jasowang@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 432e0083

drivers/net/caif/caif_virtio.c

+9 −1
Original line number Diff line number Diff line
@@ -727,13 +727,21 @@ static int cfv_probe(struct virtio_device *vdev) 
	/* Carrier is off until netdevice is opened */

	netif_carrier_off(netdev);



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

	rtnl_lock();



	/* register Netdev */

	err = register_netdev(netdev);

	err = register_netdevice(netdev);

	if (err) {

		rtnl_unlock();

		dev_err(&vdev->dev, "Unable to register netdev (%d)\n", err);

		goto err;

	}



	virtio_device_ready(vdev);



	rtnl_unlock();



	debugfs_init(cfv);



	return 0;