Re: [RFC PATCH v2 2/3] virtio/vsock: WARN_ONCE() for invalid state of socket

[Stefano Garzarella]

On Sun, Mar 26, 2023 at 01:09:25AM +0300, Arseniy Krasnov wrote:
> This adds WARN_ONCE() and return from stream dequeue callback when
> socket's queue is empty, but 'rx_bytes' still non-zero.

Nit: I would explain why we add this, for example:

This allows the detection of potential bugs due to packet merging
(see previous patch).

> 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 b9144af71553..ad70531de133 100644
> --- a/net/vmw_vsock/virtio_transport_common.c
> +++ b/net/vmw_vsock/virtio_transport_common.c
> @@ -398,6 +398,13 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
> 	u32 free_space;
>
> 	spin_lock_bh(&vvs->rx_lock);
> +
> +	if (WARN_ONCE(skb_queue_empty(&vvs->rx_queue) && vvs->rx_bytes,
> +		      "No skbuffs with non-zero 'rx_bytes'\n")) {

Nit: I would rephrase it this way:
"rx_queue is empty, but rx_bytes is non-zero"

> +		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

Anyway the patch LGTM!

Reviewed-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>