Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   "Longpeng(Mike)" <longpeng2@huawei.com>
To:     <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>
CC:     <arei.gonglei@huawei.com>, <subo7@huawei.com>,
        "Longpeng(Mike)" <longpeng2@huawei.com>,
        "David S . Miller" <davem@davemloft.net>,
        "Jakub Kicinski" <kuba@kernel.org>,
        Stefano Garzarella <sgarzare@redhat.com>,
        "Jorgen Hansen" <jhansen@vmware.com>,
        Norbert Slusarek <nslusarek@gmx.net>,
        "Andra Paraschiv" <andraprs@amazon.com>,
        Colin Ian King <colin.king@canonical.com>,
        David Brazdil <dbrazdil@google.com>,
        Alexander Popov <alex.popov@linux.com>,
        lixianming <lixianming5@huawei.com>
Subject: [RFC] vsock: notify server to shutdown when client has pending signal
Date:   Tue, 11 May 2021 17:41:27 +0800
Message-ID: <20210511094127.724-1-longpeng2@huawei.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 7BIT
Content-Type:   text/plain; charset=US-ASCII
Precedence: bulk

The client's sk_state will be set to TCP_ESTABLISHED if the
server replay the client's connect request.
However, if the client has pending signal, its sk_state will
be set to TCP_CLOSE without notify the server, so the server
will hold the corrupt connection.

            client                        server

1. sk_state=TCP_SYN_SENT         |
2. call ->connect()              |
3. wait reply                    |
                                 | 4. sk_state=TCP_ESTABLISHED
                                 | 5. insert to connected list
                                 | 6. reply to the client
7. sk_state=TCP_ESTABLISHED      |
8. insert to connected list      |
9. *signal pending* <--------------------- the user kill client
10. sk_state=TCP_CLOSE           |
client is exiting...             |
11. call ->release()             |
     virtio_transport_close
      if (!(sk->sk_state == TCP_ESTABLISHED ||
	      sk->sk_state == TCP_CLOSING))
		return true; <------------- return at here
As a result, the server cannot notice the connection is corrupt.
So the client should notify the peer in this case.

Cc: David S. Miller <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Stefano Garzarella <sgarzare@redhat.com>
Cc: Jorgen Hansen <jhansen@vmware.com>
Cc: Norbert Slusarek <nslusarek@gmx.net>
Cc: Andra Paraschiv <andraprs@amazon.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: David Brazdil <dbrazdil@google.com>
Cc: Alexander Popov <alex.popov@linux.com>
Signed-off-by: lixianming <lixianming5@huawei.com>
Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
---
 net/vmw_vsock/af_vsock.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 92a72f0..d5df908 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1368,6 +1368,7 @@ static int vsock_stream_connect(struct socket *sock, struct sockaddr *addr,
 		lock_sock(sk);
 
 		if (signal_pending(current)) {
+			vsock_send_shutdown(sk, SHUTDOWN_MASK);
 			err = sock_intr_errno(timeout);
 			sk->sk_state = TCP_CLOSE;
 			sock->state = SS_UNCONNECTED;
-- 
1.8.3.1