From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [193.142.43.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4CEA772 for ; Mon, 3 May 2021 10:02:38 +0000 (UTC) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1ldVPL-0004ic-6i; Mon, 03 May 2021 12:02:31 +0200 From: Florian Westphal To: Cc: Paolo Abeni , Florian Westphal Subject: [PATCH] mptcp: fix splat when closing unaccepted socket Date: Mon, 3 May 2021 12:02:24 +0200 Message-Id: <20210503100224.22433-1-fw@strlen.de> X-Mailer: git-send-email 2.26.3 X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Paolo Abeni If userspace exits before calling accept() on a listener that had at least one new connection ready, we get: Attempt to release TCP socket in state 8 This happens because the mptcp socket gets cloned when the TCP connection is ready, but the socket is never exposed to userspace. The client additionally sends a DATA_FIN, which brings connection into CLOSE_WAIT state. This in turn prevents the orphan+state reset fixup in mptcp_sock_destruct() from doing its job. Fixes: 3721b9b64676b ("mptcp: Track received DATA_FIN sequence number and add related helpers") Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/185 Tested-by: Florian Westphal Signed-off-by: Paolo Abeni --- net/mptcp/subflow.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 15620bafc544..01f30f8ea710 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -546,8 +546,7 @@ static void mptcp_sock_destruct(struct sock *sk) * ESTABLISHED state and will not have the SOCK_DEAD flag. * Both result in warnings from inet_sock_destruct. */ - - if (sk->sk_state == TCP_ESTABLISHED) { + if ((1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) { sk->sk_state = TCP_CLOSE; WARN_ON_ONCE(sk->sk_socket); sock_orphan(sk); -- 2.26.3