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 2151F350285; Wed, 3 Dec 2025 16:17:04 +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=1764778625; cv=none; b=BAQcbowe4BtncjTrNOvdnKxJ4Q/T1vqGfEbQWyISv3M2Llw2y7gLVj8tkZKrNm6bmL4QR0PsIVvuvfdAu4jtViG+Us+6EjQDd27jOi54NZ945tnJ7U9E1NKQ4bqco1zheTPhxQUYCLsUT1B5CkxRdmuMVrit0mEVt405X6tCUNw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764778625; c=relaxed/simple; bh=1ti+wOn1pxFy6srM31h5drzQE6ff4XuSxNjNUXuWysw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iWYsq722L+R34oh7rUuLbI1GstyB4Mq0T+VBjfQW4ZfKwcUq2ybPjCMkoHhOy9pZbqBtlQ+6bg8o2RXcAbSbzgfFozp15KKSV3ECw18IYtyWm3+cDOni4qHM+tyES3DKW2a+RTsZyPGbacyNywXBRbrCCzZqFZQM0Knn7or25bw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1dmrc7ZB; 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="1dmrc7ZB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 921D3C4CEF5; Wed, 3 Dec 2025 16:17:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1764778623; bh=1ti+wOn1pxFy6srM31h5drzQE6ff4XuSxNjNUXuWysw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1dmrc7ZBkQ9XYio99Bonj+YnVOtydp5H4EWK8okZ3kp2RooPoa5zMnx0TT5lzannC SE2P9FF49NhmnMzMfd+gSe7b3VkDy6nQG/sxbvn6MVr/FlPBdhlREURSpmVssZunfO QyDLaDXBMdy3Y/dVm4/dlprO6lqzCvzTARW5Yono= 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 6.1 010/568] mptcp: pm: in-kernel: C-flag: handle late ADD_ADDR Date: Wed, 3 Dec 2025 16:20:12 +0100 Message-ID: <20251203152441.035270415@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251203152440.645416925@linuxfoundation.org> References: <20251203152440.645416925@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 6.1-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 Signed-off-by: Greg Kroah-Hartman --- net/mptcp/pm_netlink.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -623,6 +623,10 @@ static void mptcp_pm_create_subflow_or_s } subflow: + /* No need to try establishing subflows to remote id0 if not allowed */ + if (mptcp_pm_add_addr_c_flag_case(msk)) + goto exit; + /* check if should create a new subflow */ while (msk->pm.local_addr_used < local_addr_max && msk->pm.subflows < subflows_max) { @@ -654,6 +658,8 @@ subflow: __mptcp_subflow_connect(sk, &local.addr, &addrs[i]); spin_lock_bh(&msk->pm.lock); } + +exit: mptcp_pm_nl_check_work_pending(msk); }