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Date:   Tue, 27 Jun 2023 09:53:30 +0200
From:   Stefano Garzarella <sgarzare@redhat.com>
To:     Arseniy Krasnov <avkrasnov@sberdevices.ru>
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>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@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
Subject: Re: [RFC PATCH v4 06/17] vsock: check error queue to set EPOLLERR
Message-ID: <pnbag2axu2uy7w2wrgiljutr3hifo3rltvkkc46wlrmhwzqr5b@pgaqr2m3iwof>
References: <20230603204939.1598818-1-AVKrasnov@sberdevices.ru>
 <20230603204939.1598818-7-AVKrasnov@sberdevices.ru>
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 <94a133e5-a180-a9b5-91cb-c0ca44af35ea@sberdevices.ru>
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In-Reply-To: <94a133e5-a180-a9b5-91cb-c0ca44af35ea@sberdevices.ru>
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On Tue, Jun 27, 2023 at 07:44:25AM +0300, Arseniy Krasnov wrote:
>
>
>On 26.06.2023 19:04, Stefano Garzarella wrote:
>> On Sat, Jun 03, 2023 at 11:49:28PM +0300, Arseniy Krasnov wrote:
>>> If socket's error queue is not empty, EPOLLERR must be set. Otherwise,
>>> reader of error queue won't detect data in it using EPOLLERR bit.
>>>
>>> Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
>>> ---
>>> net/vmw_vsock/af_vsock.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> This patch looks like it can go even without this series.
>>
>> Is it a fix? Should we add a fixes tag?
>
>Yes, it is fix and I can exclude it from this set to reduce number
>of patches, but there is no reproducer for this without MSG_ZEROCOPY
>support - at this moment this feature is the only user of error queue
>for AF_VSOCK.

Okay, so it's fine to keep it here, but please mention in the comment 
that without MSG_ZEROCOPY it can't be reproduced.

That way we know that we don't have to backport into the stable 
branches.

Thanks,
Stefano

>
>Thanks, Arseniy
>
>>
>> Thanks,
>> Stefano
>>
>>>
>>> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>>> index efb8a0937a13..45fd20c4ed50 100644
>>> --- a/net/vmw_vsock/af_vsock.c
>>> +++ b/net/vmw_vsock/af_vsock.c
>>> @@ -1030,7 +1030,7 @@ static __poll_t vsock_poll(struct file *file, struct socket *sock,
>>> ????poll_wait(file, sk_sleep(sk), wait);
>>> ????mask = 0;
>>>
>>> -??? if (sk->sk_err)
>>> +??? if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
>>> ??????? /* Signify that there has been an error on this socket. */
>>> ??????? mask |= EPOLLERR;
>>>
>>> --?
>>> 2.25.1
>>>
>>
>