From mboxrd@z Thu Jan 1 00:00:00 1970 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 EF9B9C433F5 for ; Mon, 31 Jan 2022 17:17:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350196AbiAaRRf (ORCPT ); Mon, 31 Jan 2022 12:17:35 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47738 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350146AbiAaRRe (ORCPT ); Mon, 31 Jan 2022 12:17:34 -0500 Received: from mail-il1-x12d.google.com (mail-il1-x12d.google.com [IPv6:2607:f8b0:4864:20::12d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 17649C06173B for ; Mon, 31 Jan 2022 09:17:34 -0800 (PST) Received: by mail-il1-x12d.google.com with SMTP id q11so3825808ild.11 for ; Mon, 31 Jan 2022 09:17:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mbuki-mvuki-org.20210112.gappssmtp.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=7FMF5d4y464/mBG+xgnW5AJzOcYV63lfjmbJHbKUYyU=; b=UwueWjOowGG9RoghSXrun46QDMCi3GoMJyAPkybLGed7comdsxsY2etq9o4kWeqD8d QcriPVfGnMdYOqKYOaXkcRniAdGl/FhQpc5KnXkVbJXNnx4yQFi7068Jzvsy+OdY0Yj/ ZFa64V3MwcoXR0Lm56ebc6+zMkmyeAdIldQB2jCzB3kdOBuDKzgCQaiRr9doj23/n/Jc LNKkMdbiBYKtKqWovgIFZDiyTTqPMjUOxAyoOWrnWwlWL/RWOq+/EQh5AkYDjKGWerRM 3zlQKOmKHv5fAhKYT/rvyb7vCNbLZpY0VuAi94Xub/kf/EHSxudndjNa1ITPC3NWD87v X6uw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=7FMF5d4y464/mBG+xgnW5AJzOcYV63lfjmbJHbKUYyU=; b=fRlbY8lw+W6A7hbfGYqu3DXqC1dGbCWlRJ8Ju0jsqkfs7T+w6tTlvI2Ew6AsAqS4Gq /JjbvwwdK1TQ7NYvocps6oMYp2vysGE8Q45vs0i4H8Pmwcnb3mx3sY0xW2E0/bfVxYgh CDOr6+wscbIaRanZbl1A6srcWLAlGP6GjtLmwSbDga/G4PLd/OqMy6lJnxndsCDrncMg nRux9MsulLXjbiNhJ4KZdrihifLn66XRyL1bD7F4n4NNi52ILGi9jvo2Uz5ESQYw+Fqk wrFgPiWcXq3YQU49VuolyOf4nIynxCM3IazjvZc9/wXXFDDf4RHkGsXBmBsYubAmlD0g n+Cg== X-Gm-Message-State: AOAM533N7XRIxgOWPJ4iE60M1maoi1uD9JLBBBL9yY8xFAHr4Rxi2R6D 3JGMTTfGSBRQ4biFpR26kAOVdw== X-Google-Smtp-Source: ABdhPJxAPbl4lIWo/zl/wBMjezsPxPZpgneEeANeylpou0230Vt3jxB5ymE7ds/N5HABAwYzorMKLA== X-Received: by 2002:a05:6e02:20e1:: with SMTP id q1mr13387664ilv.172.1643649453386; Mon, 31 Jan 2022 09:17:33 -0800 (PST) Received: from localhost (c-73-73-44-208.hsd1.il.comcast.net. [73.73.44.208]) by smtp.gmail.com with UTF8SMTPSA id q4sm7815726ilv.5.2022.01.31.09.17.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 31 Jan 2022 09:17:33 -0800 (PST) From: Jesse Hathaway To: ycheng@google.com Cc: davem@davemloft.net, edumazet@google.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, ncardwell@google.com, pavel@denx.de, sashal@kernel.org, soheil@google.com, stable@vger.kernel.org, weiwan@google.com, jesse@mbuki-mvuki.org Subject: Re: [PATCH 5.10 099/167] tcp: disable TFO blackhole logic by default Date: Mon, 31 Jan 2022 11:17:32 -0600 Message-Id: <20220131171732.1018990-1-jesse@mbuki-mvuki.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Wed, Jul 28, 2021 at 09:32:42 -0700 Yuchung Cheng wrote: > On the other hand maybe we do not hear middlebox issues because this > mechanism is working. So I am okay to avoid applying to stable and > keep in net-next to test this new policy. This change did indeed break our mail servers at Wikimedia, causing difficult to diagnose timeout errors on sending outgoing email. I resorted to bisecting the kernel, which resulted in finding this commit. I have verified that reverting the sysctl value for tcp_fastopen_blackhole_timeout_sec to 3600 does resolve the timeouts. Given that it is not clear how a user would discover that this sysctl has changed, or know how to fix a middle box somewhere on a path to their destination, I would love to see this change reverted. Yours kindly, Jesse Hathaway