From 52557dbc7538ecceb27ef2206719a47a8039a335 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Fri, 19 Feb 2021 18:35:40 +0100 Subject: mptcp: do not wakeup listener for MPJ subflows MPJ subflows are not exposed as fds to user spaces. As such, incoming MPJ subflows are removed from the accept queue by tcp_check_req()/tcp_get_cookie_sock(). Later tcp_child_process() invokes subflow_data_ready() on the parent socket regardless of the subflow kind, leading to poll wakeups even if the later accept will block. Address the issue by double-checking the queue state before waking the user-space. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/164 Reported-by: Dr. David Alan Gilbert Fixes: f296234c98a8 ("mptcp: Add handling of incoming MP_JOIN requests") Reviewed-by: Mat Martineau Signed-off-by: Paolo Abeni Signed-off-by: Jakub Kicinski --- net/mptcp/subflow.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'net') diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 06e233410e0e..e1fbcab257e6 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1096,6 +1096,12 @@ static void subflow_data_ready(struct sock *sk) msk = mptcp_sk(parent); if (state & TCPF_LISTEN) { + /* MPJ subflow are removed from accept queue before reaching here, + * avoid stray wakeups + */ + if (reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue)) + return; + set_bit(MPTCP_DATA_READY, &msk->flags); parent->sk_data_ready(parent); return; -- cgit v1.2.3-59-g8ed1b