From nobody Sun Mar 22 09:59:42 2026 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 4303F3C6A38; Tue, 3 Mar 2026 10:56:32 +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=1772535393; cv=none; b=PjLo3Vn/oIz3u88VQot6DSPuzVjkcsKecWK9oUczxA9MVwKSKwhAIJaS8ucvQsBjYPF5vliR/Yn0Y6MXCc2EJukh9m86ebTHgWRoQfiUtVCKwhWTfcCIJyi15/FTLCiNoO5AFhNPova0dc03904F3SduQSxdUuy0PL4Z0MeY9pc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772535393; c=relaxed/simple; bh=B5z+KFhPcJgXrbHNEA47/crWzvwpnRXOTRs7q3iRcvQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=SmakifbC9ScKEwyFURnsrumzEqHAIM4tijsdXtf796YZkwp0WIDMMDzpUODx9rl01yCSe6GIOG/yeFoZ7/aFItq627X5qG5KiiqrKU8cSswQbecM3IMy5J7DUFosCtJz+czUQAE+2IQ0l0R46ozCWvQNg954mkdZ9X9tgMycaq0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZVBlOtns; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZVBlOtns" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7997FC2BCAF; Tue, 3 Mar 2026 10:56:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772535392; bh=B5z+KFhPcJgXrbHNEA47/crWzvwpnRXOTRs7q3iRcvQ=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=ZVBlOtnsUMPDAs6I6F1/i5cmGiL2gvN+AhZZWDL9dXq6522ssqXi8O2KQRelUbROE ri5fykPoprgoZ4O4q/BDBRbxfIgPEMxvNCeXqByceTVoafaQCm3XQekDtl1stW+KLR 8BO2t7gpyyky9fQP1Ql71dJzlAt5DmAuwTuFC1z40C/vruaWD2Wa8AbBP4WABryjfh Tyd9pBPYa00FWBzisAMiByPYgO1hRbNU8dl+OOi8a+Cxxe10CP0hgYHPOQtsdquwMc m7cxfaxE4XVdt93994fq7XGwZ+ca7alZKXq0zqq/1wlUgPJG1p6dE+h6kevM8+9J2I WI75v7k1PJrkw== From: "Matthieu Baerts (NGI0)" Date: Tue, 03 Mar 2026 11:56:03 +0100 Subject: [PATCH net 2/5] mptcp: pm: avoid sending RM_ADDR over same subflow Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260303-net-mptcp-misc-fixes-7-0-rc2-v1-2-4b5462b6f016@kernel.org> References: <20260303-net-mptcp-misc-fixes-7-0-rc2-v1-0-4b5462b6f016@kernel.org> In-Reply-To: <20260303-net-mptcp-misc-fixes-7-0-rc2-v1-0-4b5462b6f016@kernel.org> To: Mat Martineau , Geliang Tang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Shuah Khan Cc: netdev@vger.kernel.org, mptcp@lists.linux.dev, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, "Matthieu Baerts (NGI0)" , stable@vger.kernel.org, Frank Lorenz X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=3512; i=matttbe@kernel.org; h=from:subject:message-id; bh=B5z+KFhPcJgXrbHNEA47/crWzvwpnRXOTRs7q3iRcvQ=; b=owGbwMvMwCVWo/Th0Gd3rumMp9WSGDKX7QvqNAktqJRWKfSu3OVo6Mb23PLWz9PXVHTrGf1Fu V4EJt3rKGVhEONikBVTZJFui8yf+byKt8TLzwJmDisTyBAGLk4BmIhPEcM/peN54lueXTe4mf5b VL7le3X6W+7I6KmTYiLe7snJ+HNrA8P/8JtHHs+05u80btpgvFNj1jx+54p/Nun8Qb1fezelJIr wAgA= X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 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) --- net/mptcp/pm.c | 55 +++++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 43 insertions(+), 12 deletions(-) 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); } =20 -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 =3D NULL; + u8 i, id =3D subflow_get_local_id(subflow); + + for (i =3D 0; i < rm_list->nr; i++) { + if (rm_list->ids[i] =3D=3D 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 =3D NULL, *same_id =3D NULL; =20 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; =20 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; =20 - if (!alt) - alt =3D subflow; + if (unlikely(subflow->stale)) { + if (!stale) + stale =3D subflow; + } else if (unlikely(rm_list && + subflow_in_rm_list(subflow, rm_list))) { + if (!same_id) + same_id =3D subflow; + } else { + goto send_ack; } } =20 - if (alt) - mptcp_pm_send_ack(msk, alt, false, false); + if (same_id) + subflow =3D same_id; + else if (stale) + subflow =3D 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); } =20 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 =3D *rm_list; rm_addr |=3D 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; } =20 --=20 2.51.0