Re: [RFC PATCH v1 2/3] virtio/vsock: add WARN() for invalid state of socket

[Stefano Garzarella]

On Sun, Mar 19, 2023 at 09:52:19PM +0300, Arseniy Krasnov wrote:
> This prints WARN() and returns from stream dequeue callback when socket's
> queue is empty, but 'rx_bytes' still non-zero.
>
> Signed-off-by: Arseniy Krasnov <AVKrasnov@xxxxxxxxxxxxxx>
> ---
> net/vmw_vsock/virtio_transport_common.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
> index 3c75986e16c2..c35b03adad8d 100644
> --- a/net/vmw_vsock/virtio_transport_common.c
> +++ b/net/vmw_vsock/virtio_transport_common.c
> @@ -388,6 +388,13 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
> 	u32 free_space;
>
> 	spin_lock_bh(&vvs->rx_lock);
> +
> +	if (skb_queue_empty(&vvs->rx_queue) && vvs->rx_bytes) {
> +		WARN(1, "No skbuffs with non-zero 'rx_bytes'\n");

I would use WARN_ONCE, since we can't recover so we will flood the log.

And you can put the condition in the first argument, I mean something
like this:
        if (WARN_ONCE(skb_queue_empty(&vvs->rx_queue) && vvs->rx_bytes,
                      "rx_queue is empty, but rx_bytes is non-zero\n")) {

Thanks,
Stefano

> +		spin_unlock_bh(&vvs->rx_lock);
> +		return err;
> +	}
> +
> 	while (total < len && !skb_queue_empty(&vvs->rx_queue)) {
> 		skb = skb_peek(&vvs->rx_queue);
>
> --
> 2.25.1