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=-8.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham 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 0DCD2C04AB4 for ; Tue, 14 May 2019 06:12:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C58502086A for ; Tue, 14 May 2019 06:12:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="s04kzuOF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726277AbfENGMo (ORCPT ); Tue, 14 May 2019 02:12:44 -0400 Received: from mail-it1-f179.google.com ([209.85.166.179]:55818 "EHLO mail-it1-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725866AbfENGMo (ORCPT ); Tue, 14 May 2019 02:12:44 -0400 Received: by mail-it1-f179.google.com with SMTP id q132so3037544itc.5 for ; Mon, 13 May 2019 23:12:43 -0700 (PDT) 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=xnw1iV8ZqN4Kd9CmWcXfMF7LhA77hZc0Y/HrDuqtO9Y=; b=s04kzuOFQ610XOtg3ZNx3FTnNBcRUkBvjrpxDqyk8a8unA9cA+CV4sYalQMXhV0KRh O8zh/wK8ZB84h7quPNwW4+Z0bkkJEGLChHQ3sxRgeUDFtogHgLeI/doYy5v0M5gj+D0r OseFj21+7/ygcKQ/qDdF3qSycpqffG6r1wp6FEwO2bMt4z+ZNdht4E+mYzGOY4/o7cyC 5yyNrP44I0XQeq88pjAJxSkizr35jdQUsbFCa0H7Xge/twWFIKQp6iDHwBAClkcJdLgV Ka4BKbzRk8ADtetuG7n/E6KwyvxhOYeaXKJ4CylgLgAqtEBlh5wbL3f7Pk6/gwcSY9yK 6drw== 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=xnw1iV8ZqN4Kd9CmWcXfMF7LhA77hZc0Y/HrDuqtO9Y=; b=WEjh9vVpNbAPwUR1x5c5awUeHlSjh5vB01Dc2d3SLnW61MPXW7uK82uNg6fSpcdaHH I42I91NzDS/0bspPcDA2hjsBnAUufxHCKugbltT4jIbO7ix1Y+i0G0aI4izLGjG5iG/g 2gFHFGnqUmpmHNv2p40z5aetPaFDNi6CEqZkpMab/itIT4CnlBvlVqibaNEkwv0cIz7j wCnmvpyQ2FKe1BqKkw60lxJynHmOnOnR2keD2CBrEYjZ3BOCaMCD1DJdt2K+RS2zBLk/ 6xiTYQDk7Vtldn7XW0V789flNZLg42XHwWMiFECBbeVeLFTaBtPxs7z7I7StZthn0o3y TAjA== X-Gm-Message-State: APjAAAWnz2t0GViJCTJldTGLNaw9qPSK0gTGvir+XlDlOKh2vtoT4aF8 xrqDHsp98Zu2pMP7M1fpBr3kzNVpjLmHOMm8odhjlw== X-Google-Smtp-Source: APXvYqxfOnghVOewngiLIbaRTq+LI5LJprMzP3uxEErVpeqx1g4JEi0xm2OMGI+V9vpfbdS+huWR52tpzHdoLFH1GIw= X-Received: by 2002:a24:eb09:: with SMTP id h9mr2471279itj.14.1557814362770; Mon, 13 May 2019 23:12:42 -0700 (PDT) MIME-Version: 1.0 References: <71e7331f-d528-430e-f880-e995ff53d362@lists.m7n.se> <2667a075-7a51-d1e0-c4e7-cf0d011784b9@gmail.com> In-Reply-To: <2667a075-7a51-d1e0-c4e7-cf0d011784b9@gmail.com> From: Wei Wang Date: Mon, 13 May 2019 23:12:31 -0700 Message-ID: Subject: Re: IPv6 PMTU discovery fails with source-specific routing To: David Ahern , Mikael Magnusson Cc: Linux Kernel Network Developers , Martin KaFai Lau Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Thanks Mikael for reporting this issue. And thanks David for the bisection. Let me spend some time to reproduce it and see what is going on. From: David Ahern Date: Mon, May 13, 2019 at 8:35 PM To: Mikael Magnusson, , Martin KaFai Lau, Wei Wang > On 5/13/19 1:22 PM, Mikael Magnusson wrote: > > Hello list, > > > > I think I have found a regression in 4.15+ kernels. IPv6 PMTU discovery > > doesn't seem to work with source-specific routing (AKA source-address > > dependent routing, SADR). > > > > I made a test script (see attachment). It sets up a test environment > > with three network namespaces (a, b and c) using SADR. The link between > > b and c is configured with MTU 1280. It then runs a ping test with large > > packets. > > > > I have tested a couple of kernels on Ubuntu 19.04 with the following > > results. > > > > mainline 4.14.117-0414117-generic SUCCESS > > ubuntu 4.15.0-1036-oem FAIL > > mainline 5.1.0-050100-generic FAIL > > > > git bisect shows > > good: 38fbeeeeccdb38d0635398e8e344d245f6d8dc52 > bad: 2b760fcf5cfb34e8610df56d83745b2b74ae1379 > > Those are back to back commits so > 2b760fcf5cfb ipv6: hook up exception table to store dst cache > > has to be the bad commit. > > Your patch may work, but does not seem logical relative to code at the > time of 4.15 and the commit that caused the failure. cc'ing authors of > the changes referenced above.