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 X-Spam-Level: X-Spam-Status: No, score=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF12DC433E6 for ; Sun, 24 Jan 2021 00:20:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7901922795 for ; Sun, 24 Jan 2021 00:20:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726408AbhAXAUP (ORCPT ); Sat, 23 Jan 2021 19:20:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725943AbhAXAUN (ORCPT ); Sat, 23 Jan 2021 19:20:13 -0500 Received: from mail-vs1-xe35.google.com (mail-vs1-xe35.google.com [IPv6:2607:f8b0:4864:20::e35]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52BEAC0613D6 for ; Sat, 23 Jan 2021 16:19:33 -0800 (PST) Received: by mail-vs1-xe35.google.com with SMTP id o125so5251218vsc.6 for ; Sat, 23 Jan 2021 16:19:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=gqojlmdONECs4eHvvUDkwp6TSunCOtW2jlVrU1HsYSw=; b=WrID38WFY3Kl4vdm5ExYcrwrwKP9kg3pQxlmAwIm9EFWV3Qn18BW8O9957j9rWFvPE r1KbVX+ztzxWT6t0auZu702NUKMClae6AslebMZNy7Bu8V0IZ6JyO0Y+CiQwMKlywiGD jSnQVY7hW+y1CCyyqc/eGfoFNyt+LLLIFumRK/GPR1GUGbTTcikxcTzDPtVmyqfuSIgf Mmu1BV6qWiNGSxBz36U50+Fgg8ZcYV2d0M416vl0gUqBf5jObj/UwedCOQaBsu4ezwF8 7Onm9TSYPP6BTDBEDZ4Rcsd8zNw1n7liCmuQziaxU3IP3mVNwG7/FqtaIz8nje1TpstQ Aakg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=gqojlmdONECs4eHvvUDkwp6TSunCOtW2jlVrU1HsYSw=; b=SEbJKxZ02m6TWMSZcA6CWYvKD3Nk7+v5MjwNabqfGxVgZVEDUNHtaDll+WzMRLSShP gK620u3gPvV9wqwq5WvujNv7ADd1K0fbNLzTdlYDdUGrljDYxub0vNTCTHm4svXB2gR9 xagDW/Z9p11B3FrrMXC52Y1QAjnCHttEhdKn1uc10ch43HQzY+H2YMabu0MOSuJNTtfv c67UaMJepl+7/aXvn/7p2tF/nGdXeFyKLFnE7AzttQ7MUBy+TFmxRWZt9bmmjo3URLtv 5PE2DSPq5JCBWKdMYSMUzT6UxapsMQznV/sL+z70dhbRXiH0sani/Ox8CsBSMJyOXdCs TbDg== X-Gm-Message-State: AOAM5326axlmOA1AIIaN2snyev/jZrahuI7oAlKA6Qr5bORw4x0FARTP kPrtLjhME284IFfVi2z6KLpN0vsODRqIir/1Z4oC0g== X-Google-Smtp-Source: ABdhPJxWXbSoeCQXL2gzdTjGYVCoKu+u2qVcYnhT9QGKUtTVhjFyrYf+goC1NWH4UF8UgL96y8oorEcu6KHGohfsvLI= X-Received: by 2002:a67:e195:: with SMTP id e21mr169364vsl.16.1611447570734; Sat, 23 Jan 2021 16:19:30 -0800 (PST) MIME-Version: 1.0 References: <20210122191306.GA99540@localhost.localdomain> <20210122174325.269ac329@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210123022823.GA100578@localhost.localdomain> <20210122183424.59c716a1@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210123024534.GB100578@localhost.localdomain> In-Reply-To: <20210123024534.GB100578@localhost.localdomain> From: Neal Cardwell Date: Sat, 23 Jan 2021 19:19:13 -0500 Message-ID: Subject: Re: [PATCH net] tcp: make TCP_USER_TIMEOUT accurate for zero window probes To: Enke Chen Cc: Jakub Kicinski , Eric Dumazet , "David S. Miller" , Alexey Kuznetsov , Hideaki YOSHIFUJI , Netdev , LKML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Jan 22, 2021 at 9:45 PM Enke Chen wrote: > > Hi, Jakub: > > On Fri, Jan 22, 2021 at 06:34:24PM -0800, Jakub Kicinski wrote: > > On Fri, 22 Jan 2021 18:28:23 -0800 Enke Chen wrote: > > > Hi, Jakub: > > > > > > In terms of backporting, this patch should go together with: > > > > > > 9d9b1ee0b2d1 tcp: fix TCP_USER_TIMEOUT with zero window > > > > As in it: > > > > Fixes: 9d9b1ee0b2d1 tcp: fix TCP_USER_TIMEOUT with zero window > > > > or does it further fix the same issue, so: > > > > Fixes: 9721e709fa68 ("tcp: simplify window probe aborting on USER_TIMEOUT") > > > > ? > > Let me clarify: > > 1) 9d9b1ee0b2d1 tcp: fix TCP_USER_TIMEOUT with zero window > > fixes the bug and makes it work. > > 2) The current patch makes the TCP_USER_TIMEOUT accurate for 0-window probes. > It's independent. Patch (2) ("tcp: make TCP_USER_TIMEOUT accurate for zero window probes") is indeed conceptually independent of (1) but its implementation depends on the icsk_probes_tstamp field defined in (1), so AFAICT (2) cannot be backported further back than (1). Patch (1) fixes a bug in 5.1: Fixes: 9721e709fa68 ("tcp: simplify window probe aborting on USER_TIMEOUT") So probably (1) and (2) should be backported as a pair, and only back as far as 5.1. (That covers 2 LTS kernels, 5.4 and 5.10, so hopefully that is good enough.) neal