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");
+		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

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
>

On 20.03.2023 18:07, Stefano Garzarella wrote:
> 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")) {
I see, ok.
> 
> 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
>>
>