From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794049672; b=CDlj2UTfWGQlJv4Ffn1oI3pD51dIsgQ7QcBuctkQV4VgHiNeiCamf2ZAKPxGzvyQnXa6 k96yUsq7lAHsZKFRrfHGvEporNmPYyIVsAzqUsvM86N04kTE5GIFbN/DNFcFQuSUGjPYm EUulJ4HacGgV3jtiI99b7ptKl3tNwKIETe0uD5ZHnT4wzzTGIGtl+UvDuhlzLYYO3Kr02 MRMPeS+sEPCtHPO6FBYOv8T8TVlRVd4PhmL4rE8Cl94xFab+AmnWeQziLkRnb7Ro34mga Ck/7mc58a+C0nPKOXs0PhUYkpBjAlJeajcnyEOpSbLwbDYJ5M4s8E7mn89NlWC2GNiQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794049672; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=o/PdgCaefsS8NbcQ8UKVlxeeIW70g6dsQVJk26xjdBA=; b=Ko8HZogC6jGU0I5AeEPVIDR2DO8jQVffIw6uSxt45KieNyhPij5aIx7bSxCqCFPEB1Ey wWReoVXPPL/Ba/US0e3CjoFO8rnb/ZG6LWias7Stj/MLFCeCtNsRnXQnKm2aS9F75G8J2 CdDbyLA7TgjXGeym9yGavELk20bmDX/+k/rtekwkcyaYSpElK02hdt0Am5AgR1jFa1zfq Lbwz4+N1EApLbewdMMgblhLpteyaXxWWrblYI6YAEvvIq2/SnWs9IvidP5kyOl9rcFhkT MQRiXDq6O2jYyvKJb+KiMZIGsbSwc/8MqlLaCDhvU7oM9EQfIha4bGVYn9j9MSmOD/w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=RDzzRH2q; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 36404606A326 for ; Sat, 7 Nov 2026 11:07:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=RDzzRH2q Received: by smtp.kernel.org (Postfix) with ESMTPSA id 91DAF1F0089F; Sat, 7 Nov 2026 11:07:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794049672; bh=o/PdgCaefsS8NbcQ8UKVlxeeIW70g6dsQVJk26xjdBA=; h=From:To:Cc:Subject:Date; b=RDzzRH2q09kGL1qNAjK6yaUL3H213dsq/CEvzDxCzeKLBag8Ayjh8X0RwtpOt+qQQ MHFMJy1mag9ZnG8pClhtYC38smHzyHgvYx8IdP+U7Aapy1jCwW2Imv1+GQWESkdb7U BA1xZnshtftRDHcqNQCrHp4G9blwbsYPGNEJzGGqEzJI2hMjtOoy7966gW0CQX1FNI 5jwWfGKNg10fIebWIYqLE16AONhu1X637UevRX9NiJO0FuY5ewm8bZgktY+MDIK7j2 vOwj6WRYXTxavW+aDF4saY7L/iUPXmA6Q5h2Luwo5ziYH8BoykTJnnFi5NMYojUKXB qBK5SNAecwg/Q== From: Sasha Levin To: quanyeyang@proton.me, matttbe@kernel.org, kuba@kernel.org Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] mptcp: reset msk state on early connect failure" failed to apply to 5.15-stable tree Date: Sat, 7 Nov 2026 06:07:50 -0500 Message-ID: <20261107060750-failed-5.15-29afe67082b2@kernel.org> X-Mailer: git-send-email 2.53.0 X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 29afe67082b2d33ab2e90c56c337235d725f023f # git commit -s git send-email --to '' --in-reply-to '20261107060750-failed-5.15-29afe67082b2@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 29afe67082b2d33ab2e90c56c337235d725f023f Mon Sep 17 00:00:00 2001 From: Quanye Yang Date: Tue, 13 Oct 2026 16:29:19 +0200 Subject: [PATCH] mptcp: reset msk state on early connect failure mptcp_connect() can fall back before the subflow SYN is sent, for example when the netns is in an MPTCP blackhole, token allocation fails, or MD5SIG is in use. If the subsequent subflow connect() fails immediately (EAFNOSUPPORT, ENETUNREACH, ...), __inet_stream_connect() returns while the socket is still SS_UNCONNECTED and never calls ->disconnect(). This was reported by Clashiko [1]. The error path only dropped the token and moved the msk back to TCP_CLOSE. MPTCP_FALLBACK_DONE, allow_subflows and request_mptcp were left as after early fallback, so a later connect() on the same fd stayed TCP-only. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/633 [1] Fixes: 0235d075a592 ("mptcp: mark as fallback even early ones") Cc: stable@vger.kernel.org Signed-off-by: Quanye Yang Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20261013-net-mptcp-misc-fixes-7-3-rc8-v1-1-932c9b182fc7@kernel.org Signed-off-by: Jakub Kicinski --- net/mptcp/protocol.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index e89a69ab927c9..e6f73a5ee630a 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -4212,9 +4212,16 @@ static int mptcp_connect(struct sock *sk, struct sockaddr_unsized *uaddr, * subflow_finish_connect() */ if (unlikely(err)) { - /* avoid leaving a dangling token in an unconnected socket */ mptcp_token_destroy(msk); mptcp_set_state(sk, TCP_CLOSE); + + spin_lock_bh(&msk->fallback_lock); + msk->allow_subflows = true; + msk->allow_infinite_fallback = true; + clear_bit(MPTCP_FALLBACK_DONE, &msk->flags); + spin_unlock_bh(&msk->fallback_lock); + + mptcp_subflow_ctx_reset(mptcp_subflow_ctx(ssk)); return err; } -- 2.53.0