| Message ID | 20220620051115.3142-3-jasowang@redhat.com (mailing list archive) |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Fixing races in probe/remove | expand |
On Mon, Jun 20, 2022 at 01:11:14PM +0800, Jason Wang wrote: > We used to depend on the virtio_device_ready() that is called after "We used to" implies it's not the case currently. I think you mean "we currently depend". > probe() by virtio_dev_probe() after netdev registration. This > cause causes >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 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: 0d2e1a2926b18 ("caif_virtio: Introduce caif over virtio") > Signed-off-by: Jason Wang <jasowang@redhat.com> Acked-by: Michael S. Tsirkin <mst@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
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;
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(-)