From: Paolo Abeni <pabeni@redhat.com>
Date: Thu, 11 Feb 2021 23:30:38 +0000 (-0800)
Subject: mptcp: fix poll after shutdown
X-Git-Tag: v5.15~1635^2~21^2~28^2~4
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=dd913410b0a442a53d41a9817ed2208850858e99;p=platform%2Fkernel%2Flinux-starfive.git

mptcp: fix poll after shutdown

The current mptcp_poll() implementation gives unexpected
results after shutdown(SEND_SHUTDOWN) and when the msk
status is TCP_CLOSE.

Set the correct mask.

Fixes: 8edf08649eed ("mptcp: rework poll+nospace handling")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 9eecd1383d24..42ca49954bdd 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -3321,7 +3321,7 @@ 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;
@@ -3354,6 +3354,8 @@ 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;