Re: [Patch net 2/2] vsock/virtio: Don't reset the created SOCKET during suspend to ram

[Stefano Garzarella <sgarzare@xxxxxxxxxx>]

On Tue, Feb 11, 2025 at 03:19:22PM +0800, Junnan Wu wrote:
> Function virtio_vsock_vqs_del will be invoked in 2 cases
> virtio_vsock_remove() and virtio_vsock_freeze().
>
> And when driver freeze, the connected socket will be set to TCP_CLOSE
> and it will cause that socket can not be unusable after resume.
>
> Refactor function virtio_vsock_vqs_del to differentiate the 2 use cases.
>
> Co-developed-by: Ying Gao <ying01.gao@xxxxxxxxxxx>
> Signed-off-by: Ying Gao <ying01.gao@xxxxxxxxxxx>
> Signed-off-by: Junnan Wu <junnan01.wu@xxxxxxxxxxx>
> ---
> net/vmw_vsock/virtio_transport.c | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)

We are still discussing this in v1:

https://lore.kernel.org/virtualization/iv6oalr6yuwsfkoxnorp4t77fdjheteyojauwf2phshucdxatf@ominy3hfcpxb/T/#u

Please stop sending new versions before reaching an agreement!

BTW I still think this is wrong, so:

Nacked-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>


> diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
> index f0e48e6911fc..909048c9069b 100644
> --- a/net/vmw_vsock/virtio_transport.c
> +++ b/net/vmw_vsock/virtio_transport.c
> @@ -716,14 +716,20 @@ static void virtio_vsock_vqs_start(struct virtio_vsock *vsock)
> 	queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
> }
>
> -static void virtio_vsock_vqs_del(struct virtio_vsock *vsock)
> +static void virtio_vsock_vqs_del(struct virtio_vsock *vsock, bool vsock_reset)
> {
> 	struct virtio_device *vdev = vsock->vdev;
> 	struct sk_buff *skb;
>
> -	/* Reset all connected sockets when the VQs disappear */
> -	vsock_for_each_connected_socket(&virtio_transport.transport,
> -					virtio_vsock_reset_sock);
> +	/* When driver is removed, reset all connected
> +	 * sockets because the VQs disappear.

You wrote it here too, you have to reset them because the VQs are going 
to disappear, isn't it the same after the freeze?

> +	 * When driver is just freezed, don't do that because the connected
> +	 * socket still need to use after restore.
> +	 */
> +	if (vsock_reset) {
> +		vsock_for_each_connected_socket(&virtio_transport.transport,
> +						virtio_vsock_reset_sock);
> +	}
>
> 	/* Stop all work handlers to make sure no one is accessing the device,
> 	 * so we can safely call virtio_reset_device().
> @@ -831,7 +837,7 @@ static void virtio_vsock_remove(struct virtio_device *vdev)
> 	rcu_assign_pointer(the_virtio_vsock, NULL);
> 	synchronize_rcu();
>
> -	virtio_vsock_vqs_del(vsock);
> +	virtio_vsock_vqs_del(vsock, true);
>
> 	/* Other works can be queued before 'config->del_vqs()', so we flush
> 	 * all works before to free the vsock object to avoid use after free.
> @@ -856,7 +862,7 @@ static int virtio_vsock_freeze(struct virtio_device *vdev)
> 	rcu_assign_pointer(the_virtio_vsock, NULL);
> 	synchronize_rcu();
>
> -	virtio_vsock_vqs_del(vsock);
> +	virtio_vsock_vqs_del(vsock, false);
>
> 	mutex_unlock(&the_virtio_vsock_mutex);
>
> --
> 2.34.1