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

[Stefano Garzarella <sgarzare@redhat.com>]

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@sberdevices.ru>
>---
> 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
>