Message-ID: <37bef564-8f3e-aab3-a7d7-24e6c4caa318@sberdevices.ru>
Date:   Mon, 20 Mar 2023 21:10:34 +0300
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Subject: Re: [RFC PATCH v1 2/3] virtio/vsock: add WARN() for invalid state of
 socket
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To:     Stefano Garzarella <sgarzare@redhat.com>
CC:     Stefan Hajnoczi <stefanha@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Bobby Eshleman <bobby.eshleman@bytedance.com>,
        <kvm@vger.kernel.org>, <virtualization@lists.linux-foundation.org>,
        <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <kernel@sberdevices.ru>, <oxffffaa@gmail.com>
References: <e141e6f1-00ae-232c-b840-b146bdb10e99@sberdevices.ru>
 <da93402d-920e-c248-a5a1-baf24b70ebee@sberdevices.ru>
 <20230320150715.twapgesp2gj6egua@sgarzare-redhat>
From:   Arseniy Krasnov <avkrasnov@sberdevices.ru>
In-Reply-To: <20230320150715.twapgesp2gj6egua@sgarzare-redhat>
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Precedence: bulk


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
>>
>