Currently we move orphaned msk socket directly from FIN_WAIT2 state to close, with the rationale that incoming additional data could be just dropped by the TCP stack/TW sockets. Anyhow we miss sending MPTCP-level ack on incoming DATA_FIN, and that may hang the peers. Fixes: e16163b6e2b7 ("mptcp: refactor shutdown and close") Signed-off-by: Paolo Abeni <pabeni(a)redhat.com&gt; --- I hope nobody is keeping track of nr of follow-ups x commit, because the referenced one could score a world record :((( --- net/mptcp/protocol.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index ee5a2981df6da..f15c79ff6a53c 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2297,13 +2297,12 @@ static void mptcp_worker(struct work_struct *work) __mptcp_check_send_data_fin(sk); mptcp_check_data_fin(sk); - /* if the msk data is completely acked, or the socket timedout, - * there is no point in keeping around an orphaned sk + /* There is no point in keeping aroud an orphaned sk timedout or closed, + * but we need the msk around to reply to incoming DATA_FIN, even if + * orphaned and in FIN_WAIT2 state */ if (sock_flag(sk, SOCK_DEAD) && - (mptcp_check_close_timeout(sk) || - (state != sk->sk_state && - ((1 << inet_sk_state_load(sk)) & (TCPF_CLOSE | TCPF_FIN_WAIT2))))) { + (mptcp_check_close_timeout(sk) || sk->sk_state == TCP_CLOSE)) { inet_sk_state_store(sk, TCP_CLOSE); __mptcp_destroy_sock(sk); goto unlock; -- 2.26.2