netdev - Re: [PATCH] vsock: bugfix port residue in server

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Date: Thu, 11 May 2023 15:03:24 +0800
From: Zhuang Shengen <zhuangshengen@...wei.com>
To: Stefano Garzarella <sgarzare@...hat.com>
CC: <virtualization@...ts.linux-foundation.org>, <netdev@...r.kernel.org>,
	<linux-pci@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<arei.gonglei@...wei.com>, <longpeng2@...wei.com>, <jianjay.zhou@...wei.com>
Subject: Re: [PATCH] vsock: bugfix port residue in server

Hi Stefano:

在 2023/5/10 23:23, Stefano Garzarella 写道:
> Hi,
> thanks for the patch, the change LGTM, but I have the following
> suggestions:
>
> Please avoid "bugfix" in the subject, "fix" should be enough:
> https://www.kernel.org/doc/html/v4.17/process/submitting-patches.html#describe-your-changes 
>
>
> Anyway, I suggest to change the subject in
> "vsock: avoid to close connected socket after the timeout"
>
thanks for your suggestion, I will change the subject
> On Wed, May 10, 2023 at 10:25:02PM +0800, Zhuang Shengen wrote:
>> When client and server establish a connection through vsock,
>> the client send a request to the server to initiate the connection,
>> then start a timer to wait for the server's response. When the server's
>> RESPONSE message arrives, the timer also times out and exits. The
>> server's RESPONSE message is processed first, and the connection is
>> established. However, the client's timer also times out, the original
>> processing logic of the client is to directly set the state of this 
>> vsock
>> to CLOSE and return ETIMEDOUT, User will release the port. It will not
>
> What to you mean with "User" here?
>
The User means Client, I will delete the statement "User will release 
the por", it indeed difficult to understand
>> notify the server when the port is released, causing the server port 
>> remain
>>
>
> Can we remove this blank line?
>
OK
>> when client's vsock_conqnect timeout，it should check sk state is
>
> The remote peer can't trust the other peer, indeed it will receive an
> error after sending the first message and it will remove the connection,
> right?
>
If this situation happend, the server will response a RST? Anyway the 
connection will not established before timeout, The sk state wont be 
ESTABLISHED.
>> ESTABLISHED or not. if sk state is ESTABLISHED, it means the connection
>> is established, the client should not set the sk state to CLOSE
>>
>> Note: I encountered this issue on kernel-4.18, which can be fixed by
>> this patch. Then I checked the latest code in the community
>> and found similar issue.
>>
>
> In order to backport it to the stable kernels, we should add a Fixes tag:
> https://www.kernel.org/doc/html/v4.17/process/submitting-patches.html#describe-your-changes 
>
>
OK, I add a Fixes: d021c344051a ("VSOCK: Introduce VM Sockets") in the 
new patch.

I put the new patch with v2 title in the attachment, please check.
Thanks,
Shengen

> Thanks,
> Stefano
>
>> Signed-off-by: Zhuang Shengen <zhuangshengen@...wei.com>
>> ---
>> net/vmw_vsock/af_vsock.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>> index 413407bb646c..efb8a0937a13 100644
>> --- a/net/vmw_vsock/af_vsock.c
>> +++ b/net/vmw_vsock/af_vsock.c
>> @@ -1462,7 +1462,7 @@ static int vsock_connect(struct socket *sock, 
>> struct sockaddr *addr,
>>             vsock_transport_cancel_pkt(vsk);
>>             vsock_remove_connected(vsk);
>>             goto out_wait;
>> -        } else if (timeout == 0) {
>> +        } else if ((sk->sk_state != TCP_ESTABLISHED) && (timeout == 
>> 0)) {
>>             err = -ETIMEDOUT;
>>             sk->sk_state = TCP_CLOSE;
>>             sock->state = SS_UNCONNECTED;
>> -- 
>> 2.27.0
>>
>
View attachment "0001-vsock-avoid-to-close-connected-socket-after-the-time.patch" of type "text/plain" (2024 bytes)