* [PATCH net V2] virtio-net: fix race between ndo_open() and virtio_device_ready()
@ 2022-06-27 8:30 Jason Wang
2022-06-27 12:05 ` Michael S. Tsirkin
0 siblings, 1 reply; 2+ messages in thread
From: Jason Wang @ 2022-06-27 8:30 UTC (permalink / raw)
To: mst, jasowang, davem, kuba; +Cc: virtualization, netdev, linux-kernel
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: 4baf1e33d0842 ("virtio_net: enable VQs early")
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/net/virtio_net.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index db05b5e930be..8a5810bcb839 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -3655,14 +3655,20 @@ static int virtnet_probe(struct virtio_device *vdev)
if (vi->has_rss || vi->has_rss_hash_report)
virtnet_init_default_rss(vi);
- 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");
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net V2] virtio-net: fix race between ndo_open() and virtio_device_ready()
2022-06-27 8:30 [PATCH net V2] virtio-net: fix race between ndo_open() and virtio_device_ready() Jason Wang
@ 2022-06-27 12:05 ` Michael S. Tsirkin
0 siblings, 0 replies; 2+ messages in thread
From: Michael S. Tsirkin @ 2022-06-27 12:05 UTC (permalink / raw)
To: Jason Wang; +Cc: davem, kuba, virtualization, netdev, linux-kernel
On Mon, Jun 27, 2022 at 04:30:40PM +0800, Jason Wang wrote:
> 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: 4baf1e33d0842 ("virtio_net: enable VQs early")
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
I reworded the caif commit log similarly and put both on my tree.
> ---
> drivers/net/virtio_net.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index db05b5e930be..8a5810bcb839 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -3655,14 +3655,20 @@ static int virtnet_probe(struct virtio_device *vdev)
> if (vi->has_rss || vi->has_rss_hash_report)
> virtnet_init_default_rss(vi);
>
> - 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");
> --
> 2.25.1
^ permalink raw reply [flat|nested] 2+ messages in thread
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