From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 F3F4330FC3A; Wed, 3 Dec 2025 16:09:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764778173; cv=none; b=gy6FNRdHsnd8nXQEWnQzG/U297HDdr46enrtPYoCJsMsFrV6FpJSd7c/ZajNThhKcrBHKnH4jAFB8zu3N9XUEWdv8hgs9iXmvJNwiEGflnMO9MR7+EcCjcE12BXLsnYO2vavSam7eECgz8jAt95ZaP+JBUdrPNANrGyctWu1DDM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764778173; c=relaxed/simple; bh=JFsFLL3YTRY9RQOuJuMcDKua8V8fBERUoQJ6+lyMerc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GkxfAP5210tqT6cApQACtYFWX2yIvTJGiuAo7Y7S47UrFaznzRdtlOqAe3EjpTX2/eB73bDJ7Ns50p6iR5NdzUGKMkfCVj1wDrG+Qh/ZROUBONzo4iO+890PsEBKTRPr+TNta4Il3IgX88hut6Jc3zOYeMM4XO72EsyZMVDvVZE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1vJozB/D; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="1vJozB/D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5F8DEC4CEF5; Wed, 3 Dec 2025 16:09:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1764778172; bh=JFsFLL3YTRY9RQOuJuMcDKua8V8fBERUoQJ6+lyMerc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1vJozB/DOUdMIphHzrs4bHIhKE44egSQBviStAHKlBNTmEYztzNNaMN2wj3KgBqQu tNUawYwBFA6O/E3mRJIYgMC25MCoHZpojhzrYBo4qjGbHFbi+DVsOnqcJezZ48sXgf PaKzVTsh8h+wSgJ1Xp1CFUEOC5zKYq1hThErDdT0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Geliang Tang , "Matthieu Baerts (NGI0)" , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15 265/392] mptcp: pm: in-kernel: C-flag: handle late ADD_ADDR Date: Wed, 3 Dec 2025 16:26:55 +0100 Message-ID: <20251203152423.917173415@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251203152414.082328008@linuxfoundation.org> References: <20251203152414.082328008@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Matthieu Baerts (NGI0) [ Upstream commit e84cb860ac3ce67ec6ecc364433fd5b412c448bc ] The special C-flag case expects the ADD_ADDR to be received when switching to 'fully-established'. But for various reasons, the ADD_ADDR could be sent after the "4th ACK", and the special case doesn't work. On NIPA, the new test validating this special case for the C-flag failed a few times, e.g. 102 default limits, server deny join id 0 syn rx [FAIL] got 0 JOIN[s] syn rx expected 2 Server ns stats (...) MPTcpExtAddAddrTx 1 MPTcpExtEchoAdd 1 Client ns stats (...) MPTcpExtAddAddr 1 MPTcpExtEchoAddTx 1 synack rx [FAIL] got 0 JOIN[s] synack rx expected 2 ack rx [FAIL] got 0 JOIN[s] ack rx expected 2 join Rx [FAIL] see above syn tx [FAIL] got 0 JOIN[s] syn tx expected 2 join Tx [FAIL] see above I had a suspicion about what the issue could be: the ADD_ADDR might have been received after the switch to the 'fully-established' state. The issue was not easy to reproduce. The packet capture shown that the ADD_ADDR can indeed be sent with a delay, and the client would not try to establish subflows to it as expected. A simple fix is not to mark the endpoints as 'used' in the C-flag case, when looking at creating subflows to the remote initial IP address and port. In this case, there is no need to try. Note: newly added fullmesh endpoints will still continue to be used as expected, thanks to the conditions behind mptcp_pm_add_addr_c_flag_case. Fixes: 4b1ff850e0c1 ("mptcp: pm: in-kernel: usable client side with C-flag") Cc: stable@vger.kernel.org Reviewed-by: Geliang Tang Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20251020-net-mptcp-c-flag-late-add-addr-v1-1-8207030cb0e8@kernel.org Signed-off-by: Jakub Kicinski [ applied to pm_netlink.c instead of pm_kernel.c ] Signed-off-by: Sasha Levin [ I took the version from Sasha from v6.1, and fixed an additional conflict in pm_netlink.c, because commit a88c9e496937 ("mptcp: do not block subflows creation on errors") is not in this version and changed the code around: check_work_pending() is now called directly, followed by a return instead of a goto. ] Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Sasha Levin --- net/mptcp/pm_netlink.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index df46ca14ce234..e94b78a8b0ef1 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -532,6 +532,12 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk) check_work_pending(msk); } + /* No need to try establishing subflows to remote id0 if not allowed */ + if (mptcp_pm_add_addr_c_flag_case(msk)) { + check_work_pending(msk); + return; + } + /* check if should create a new subflow */ if (msk->pm.local_addr_used < local_addr_max && msk->pm.subflows < subflows_max && -- 2.51.0