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 5C72838F95F for ; Mon, 9 Mar 2026 10:29:16 +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=1773052156; cv=none; b=uF7+fwr6JHJIGhHrjsrBgveBY7HuCLqsHi/vuf1VOWm4RtncHU19YeQ+/D2tAjRa7SsqhUfP557bUT92ErxycbfDevMRhalbXcYxWmNZELMDqXkOtBXOK+teUgjcI+V2R0mFV3xZscGzeCPDZ1Jtq+Ymr7mfH6oK0/6fccHslko= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773052156; c=relaxed/simple; bh=+4i1jRUYMPn2jR0Qd2aOQam2I2flofMrnDkBZLGVSyU=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=AP0rQR7VGuDYg/Q0flAqnPRXv6GMCDBh9R9vMYPdjG6OVtlpl/XfnfUQla1LpsFDAQm9GeqTyW7u8YbJxNFv8PHhvT0Cs0fPXBsOVdTsOnM+4eJV2xXAJBHBugTsYB81pVrC3HVPc0lTuwmsg+CQ0kjVKW0Q3SxOol6p2djX+CM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=oKQf5fZh; 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="oKQf5fZh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E43A5C4CEF7; Mon, 9 Mar 2026 10:29:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1773052156; bh=+4i1jRUYMPn2jR0Qd2aOQam2I2flofMrnDkBZLGVSyU=; h=Subject:To:Cc:From:Date:From; b=oKQf5fZhUW6rZcQiPm7Ns98uhoCun9CAeMwFiXTd3PnLfYm4QjDURrLKo+nW9G5c9 WCTd0iJuYGLhIWLCGFc+IbsFh82FZmk6k1eBWkvt/uUI6k+7tGhIGUQaBy21iN5yGa UfNI1pNunXWmkVCuj7w3LgcOzSz342Ixg3BfisfY= Subject: FAILED: patch "[PATCH] mptcp: pm: avoid sending RM_ADDR over same subflow" failed to apply to 6.6-stable tree To: matttbe@kernel.org,kuba@kernel.org,lorenz-frank@web.de,martineau@kernel.org Cc: From: Date: Mon, 09 Mar 2026 11:29:05 +0100 Message-ID: <2026030905-alkaline-earphone-b901@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-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-6.6.y git checkout FETCH_HEAD git cherry-pick -x fb8d0bccb221080630efcd9660c9f9349e53cc9e # git commit -s git send-email --to '' --in-reply-to '2026030905-alkaline-earphone-b901@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From fb8d0bccb221080630efcd9660c9f9349e53cc9e Mon Sep 17 00:00:00 2001 From: "Matthieu Baerts (NGI0)" Date: Tue, 3 Mar 2026 11:56:03 +0100 Subject: [PATCH] mptcp: pm: avoid sending RM_ADDR over same subflow RM_ADDR are sent over an active subflow, the first one in the subflows list. There is then a high chance the initial subflow is picked. With the in-kernel PM, when an endpoint is removed, a RM_ADDR is sent, then linked subflows are closed. This is done for each active MPTCP connection. MPTCP endpoints are likely removed because the attached network is no longer available or usable. In this case, it is better to avoid sending this RM_ADDR over the subflow that is going to be removed, but prefer sending it over another active and non stale subflow, if any. This modification avoids situations where the other end is not notified when a subflow is no longer usable: typically when the endpoint linked to the initial subflow is removed, especially on the server side. Fixes: 8dd5efb1f91b ("mptcp: send ack for rm_addr") Cc: stable@vger.kernel.org Reported-by: Frank Lorenz Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/612 Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260303-net-mptcp-misc-fixes-7-0-rc2-v1-2-4b5462b6f016@kernel.org Signed-off-by: Jakub Kicinski diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c index 7298836469b3..57a456690406 100644 --- a/net/mptcp/pm.c +++ b/net/mptcp/pm.c @@ -212,9 +212,24 @@ void mptcp_pm_send_ack(struct mptcp_sock *msk, spin_lock_bh(&msk->pm.lock); } -void mptcp_pm_addr_send_ack(struct mptcp_sock *msk) +static bool subflow_in_rm_list(const struct mptcp_subflow_context *subflow, + const struct mptcp_rm_list *rm_list) { - struct mptcp_subflow_context *subflow, *alt = NULL; + u8 i, id = subflow_get_local_id(subflow); + + for (i = 0; i < rm_list->nr; i++) { + if (rm_list->ids[i] == id) + return true; + } + + return false; +} + +static void +mptcp_pm_addr_send_ack_avoid_list(struct mptcp_sock *msk, + const struct mptcp_rm_list *rm_list) +{ + struct mptcp_subflow_context *subflow, *stale = NULL, *same_id = NULL; msk_owned_by_me(msk); lockdep_assert_held(&msk->pm.lock); @@ -224,19 +239,35 @@ void mptcp_pm_addr_send_ack(struct mptcp_sock *msk) return; mptcp_for_each_subflow(msk, subflow) { - if (__mptcp_subflow_active(subflow)) { - if (!subflow->stale) { - mptcp_pm_send_ack(msk, subflow, false, false); - return; - } + if (!__mptcp_subflow_active(subflow)) + continue; - if (!alt) - alt = subflow; + if (unlikely(subflow->stale)) { + if (!stale) + stale = subflow; + } else if (unlikely(rm_list && + subflow_in_rm_list(subflow, rm_list))) { + if (!same_id) + same_id = subflow; + } else { + goto send_ack; } } - if (alt) - mptcp_pm_send_ack(msk, alt, false, false); + if (same_id) + subflow = same_id; + else if (stale) + subflow = stale; + else + return; + +send_ack: + mptcp_pm_send_ack(msk, subflow, false, false); +} + +void mptcp_pm_addr_send_ack(struct mptcp_sock *msk) +{ + mptcp_pm_addr_send_ack_avoid_list(msk, NULL); } int mptcp_pm_mp_prio_send_ack(struct mptcp_sock *msk, @@ -470,7 +501,7 @@ int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_ msk->pm.rm_list_tx = *rm_list; rm_addr |= BIT(MPTCP_RM_ADDR_SIGNAL); WRITE_ONCE(msk->pm.addr_signal, rm_addr); - mptcp_pm_addr_send_ack(msk); + mptcp_pm_addr_send_ack_avoid_list(msk, rm_list); return 0; }