From nobody Mon Sep 16 19:47:41 2024 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D1D6BCD37BC for ; Sat, 16 Sep 2023 10:54:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239120AbjIPKy2 (ORCPT ); Sat, 16 Sep 2023 06:54:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40326 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239093AbjIPKyD (ORCPT ); Sat, 16 Sep 2023 06:54:03 -0400 Received: from mail-wr1-x432.google.com (mail-wr1-x432.google.com [IPv6:2a00:1450:4864:20::432]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2F98BE42 for ; Sat, 16 Sep 2023 03:53:56 -0700 (PDT) Received: by mail-wr1-x432.google.com with SMTP id ffacd0b85a97d-317c3ac7339so2599668f8f.0 for ; Sat, 16 Sep 2023 03:53:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tessares.net; s=google; t=1694861635; x=1695466435; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=WqJ79R2SnJAHHfAI9dTKO9toC5LU8hBRU518BwY/FZA=; b=eMQdMrnLE7kErtVEdSa8yvR8tGJaKjcFyje8tqP9gCPRNp6htL1clQqeB8BT8cMwcO msBqVzjx3hN6T1CI2y4Nb3PcaBPdOI0YfhV7RRJ1EezasEj4cMK/PPyzxb7tg1yIAXjs Au5PV8AXs8aOqizcvgJz2IyvmTBy2Sgp3pUr9zy5SjUHgxIjrlssC1QiDBjlhELf+lTn KW7y1z6KBeZObxO9LNWue3Dyp1T7PjwhnegpD5M9ub+9Mr8bnyB1mroZL8IUWM0XGwiC OLV0iWozMqFwKM98XFxFODPTwn7tWJS6L+jUUuYkbpzFQTs5MYHtLZ1Ynm365Dv07d3z wW3A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694861635; x=1695466435; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=WqJ79R2SnJAHHfAI9dTKO9toC5LU8hBRU518BwY/FZA=; b=TyWSWGpurPMfySM3HHJcv8M92pjR8lOdiYDSm9TJwVLDGgdwjkngIwkltNJ3Cd3m2P yJ8g1qpm7vKpRcAo006rWx9vBzoNVoVaK4zKvRqC+bHgjQ4dB47DYx8e5HE/L8H7go9o q4GpfBGof5TvPY9Q2YXbF2/gzszgH6Sgt+e21x4U75xbG1WsKRnT2g+qQVYFYCEiQ7IM axR5Iz1zciPTRrV75serjQi5xJWUCh6pHSOxRavofJNwPOMeAFYTbU2H1MqazI7htiYj w5CD+RZhAG11VDaMiWYy8mRAmmWo/nIc7mJM6HHHqXa042yxln9aCVnjR+RWFpo89wVP U4Lg== X-Gm-Message-State: AOJu0YxodFjwJqgMH6iS3E71yCo9VVU1xXxNHHkvoWdbbWjf+BsReepj llfUSZ1AQ2kDLHRbfaBbQYr3hfIv5DyEcDSI7OzuulI3 X-Google-Smtp-Source: AGHT+IHsZm0HQC9qiLlex5/BpHC1RrP5Q384dz5/IrZZm1i/R4fOEFUr8sglC/57npnA1QpgbQt7dw== X-Received: by 2002:adf:ea0b:0:b0:314:15b7:20a5 with SMTP id q11-20020adfea0b000000b0031415b720a5mr3605338wrm.54.1694861635092; Sat, 16 Sep 2023 03:53:55 -0700 (PDT) Received: from vdi08.nix.tessares.net (static.219.156.76.144.clients.your-server.de. [144.76.156.219]) by smtp.gmail.com with ESMTPSA id z20-20020a7bc7d4000000b003feae747ff2sm9900743wmk.35.2023.09.16.03.53.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 16 Sep 2023 03:53:54 -0700 (PDT) From: Matthieu Baerts Date: Sat, 16 Sep 2023 12:52:45 +0200 Subject: [PATCH net 1/5] mptcp: fix bogus receive window shrinkage with multiple subflows MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20230916-upstream-net-20230915-mptcp-hanging-conn-v1-1-05d1a8b851a8@tessares.net> References: <20230916-upstream-net-20230915-mptcp-hanging-conn-v1-0-05d1a8b851a8@tessares.net> In-Reply-To: <20230916-upstream-net-20230915-mptcp-hanging-conn-v1-0-05d1a8b851a8@tessares.net> To: mptcp@lists.linux.dev, Mat Martineau , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Davide Caratti Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Matthieu Baerts , stable@vger.kernel.org X-Mailer: b4 0.12.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=1538; i=matthieu.baerts@tessares.net; h=from:subject:message-id; bh=sz+nh5NIsadTNPEpnKohPqzpae+0POVMkN8Lp2ml4e8=; b=owEBbQKS/ZANAwAIAfa3gk9CaaBzAcsmYgBlBYlAdD3Es2m1E+RxWvNs/6/5QPODTmMhRSwga qJifHcbjWyJAjMEAAEIAB0WIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZQWJQAAKCRD2t4JPQmmg cz88D/49ajLuykR6XBy8Phzep80ts3D/bLO/Wts9WXfRmd2F/xNh4N/cdCe0DbPX+wZtnmqMVKp 3pmPgHBKv08muyta2rpwqA7GylzSd0e/1ZYS3IGJ/J7hjWkNKaX4bxBxVB/q1lUb+22gSHacwKB ruuSHNc9CGczV7vsE+BACTuqa0O3WgGCFG6IgMGOnyM6Ox0sIcu6aJ7O9M2h8TRcwmNW9/17k1m OE3qmsghIv8HuxMswryoWTF7jefrzEHUIX5P6C06oCQ9Qc/usq9Y4SUWZT46ZZrCuAzkxZRbzec QeUMZMuXAov/AyzwQlqccOLUme9Ae6R0u9ofRhbBIjvr8jKaS+QVeUNekIeDgdJQOb4A7XM08Xz ILodhtl8IqGn2VuKMFL1nzNuVEaT/vXXEQ2jjIQJyP/DILkbPKpkhAWAYM2IeIYZx6ZUrF92v9N vYZX1+zPl1DW++NrwG21eNtLWuHeay7haUgFDiMiS8x561d9GjatxgQ92rv1KQn9Q5K+1Md+2j4 3Dp4lqfBYbbAs6bT8BRPuQSzWkK8zecRQHOBwvMaSpKOeRmvTeAZkHC5V5S/U9mvz2MieztvHAB xWpwFB7o4BrkrXLVpc9rNjBRaLO74SXEVxhHD0I6S+2Wgd5hKW7lxKsu2UyCwdqTf/PktTIcBaD j34N2UGTmFlme1w== X-Developer-Key: i=matthieu.baerts@tessares.net; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Paolo Abeni In case multiple subflows race to update the mptcp-level receive window, the subflow losing the race should use the window value provided by the "winning" subflow to update it's own tcp-level rcv_wnd. To such goal, the current code bogusly uses the mptcp-level rcv_wnd value as observed before the update attempt. On unlucky circumstances that may lead to TCP-level window shrinkage, and stall the other end. Address the issue feeding to the rcv wnd update the correct value. Fixes: f3589be0c420 ("mptcp: never shrink offered window") Cc: stable@vger.kernel.org Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/427 Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts --- net/mptcp/options.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/mptcp/options.c b/net/mptcp/options.c index c254accb14de..cd15ec73073e 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -1269,12 +1269,13 @@ static void mptcp_set_rwin(struct tcp_sock *tp, str= uct tcphdr *th) =20 if (rcv_wnd =3D=3D rcv_wnd_old) break; - if (before64(rcv_wnd_new, rcv_wnd)) { + + rcv_wnd_old =3D rcv_wnd; + if (before64(rcv_wnd_new, rcv_wnd_old)) { MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDCONFLICTUPDATE); goto raise_win; } MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDCONFLICT); - rcv_wnd_old =3D rcv_wnd; } return; } --=20 2.40.1