mptcp: fix poll after shutdown

The current mptcp_poll() implementation gives unexpected results after shutdown(SEND_SHUTDOWN) and and when the msk status is TCP_CLOSE. Set the correct mask. Reviewed-by: Mat Martineau <[email protected]> Signed-off-by: Paolo Abeni <[email protected]>
multipath-tcp · Feb 7, 2021 · 928f65d · 928f65d
1 parent e0d489b
commit 928f65d
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
@@ -3317,7 +3317,7 @@ static __poll_t mptcp_check_writeable(struct mptcp_sock *msk)
 	struct sock *sk = (struct sock *)msk;
 
 	if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN))
-		return 0;
+		return EPOLLOUT | EPOLLWRNORM;
 
 	if (sk_stream_is_writeable(sk))
 		return EPOLLOUT | EPOLLWRNORM;
@@ -3350,6 +3350,8 @@ static __poll_t mptcp_poll(struct file *file, struct socket *sock,
 		mask |= mptcp_check_readable(msk);
 		mask |= mptcp_check_writeable(msk);
 	}
+	if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
+		mask |= EPOLLHUP;
 	if (sk->sk_shutdown & RCV_SHUTDOWN)
 		mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;