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Subject[PATCH 2/3] caif_virtio: fix the race between virtio_device_ready() and ndo_open()
Date
We used to depend on the virtio_device_ready() that is called after
probe() by virtio_dev_probe() after netdev registration. This
cause a race between ndo_open() and virtio_device_ready(): if
ndo_open() is called before virtio_device_ready(), the driver may
start to use the device (e.g TX) before DRIVER_OK which violates the
spec.

Fixing 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: 0d2e1a2926b18 ("caif_virtio: Introduce caif over virtio")
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/net/caif/caif_virtio.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/net/caif/caif_virtio.c b/drivers/net/caif/caif_virtio.c
index c677ded81133..66375bea2fcd 100644
--- a/drivers/net/caif/caif_virtio.c
+++ b/drivers/net/caif/caif_virtio.c
@@ -719,13 +719,21 @@ 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;
--
2.25.1
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