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=-3.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 95157C4363D for ; Thu, 24 Sep 2020 02:05:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4B8172223E for ; Thu, 24 Sep 2020 02:05:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="va0e9AIO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726281AbgIXCFz (ORCPT ); Wed, 23 Sep 2020 22:05:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56122 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725208AbgIXCFz (ORCPT ); Wed, 23 Sep 2020 22:05:55 -0400 Received: from mail-yb1-xb2e.google.com (mail-yb1-xb2e.google.com [IPv6:2607:f8b0:4864:20::b2e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E7DCC0613CE for ; Wed, 23 Sep 2020 19:05:55 -0700 (PDT) Received: by mail-yb1-xb2e.google.com with SMTP id h9so1194327ybm.4 for ; Wed, 23 Sep 2020 19:05:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=frYh6tAYSKOqElnsqf4rl/3lWHPEP+L0ux8vp73dqcg=; b=va0e9AIO5rSRoeD8VkcDmdKDZKrLDY9nKOcVCtxkQMsQenEhCDIPw3WU4oXdd+rjLa TNlADA3YQSMAsJ9ZEf5bkabcYeuqNHmZTeSONY2utWXnm5YZaMEqx77VEdHyT7KCg2G4 7DAj+LRogWEtJJkgS5E6DSPKLr5M+6C+84cTk1wZzV582dBrMX+COtyBPyH3LAmUpuKt uGRG2ZPI7O6tyQG2d15tU2ypmJDbIkLPbDjRJQLblbVlLeIv3/LQTNOv9JLUGfNlc0y/ JUHzLa7JD+q1vCfvtUvfVyEmeBwJIdeO6rq0eQ2ECTcCmy6I6DyzZzcxaAKTGWoc7n+c sWfQ== 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=frYh6tAYSKOqElnsqf4rl/3lWHPEP+L0ux8vp73dqcg=; b=NXJwaW/oTkQ+c3oPmhkJAoUm8Y7W/i9f7ekSJeFbOUCXe1GDWSFgRcsDZTuzOMLuhd C1C2B1pUBIb+RG7j/WUC7C5xM8A/2hN3quv5HU74/xtAI1QV0dTJ0fpMoQ0xdePFKbg2 u2txZkvQ7fFXnBGPdUPOfgqG0F0dnPbbdlRiafvefh8Bbf+WELYVsodcwBzpJiQL86aZ 8qUI+J+a+sUn0uTdC/aZGSl0WgW+UbQYuFujpcP/iGtvSd1pM34OmK5UsiMQuvuop9WY JeWslFPtURsKQp486hzrG05q9MYDYBgE7jFoTqWRa2QW9tMkeObBHhPuQbQvuz9sMmI3 c69w== X-Gm-Message-State: AOAM531fn5uY0+HN75E4plJWOFWdrQUqY2TlpwANq73DIq/m8tHwhU6U WW6khTMlZYMWzhIW0+s5QpdDEx96oYIEoY1a6kQ= X-Google-Smtp-Source: ABdhPJw9PWou6hCBKKX9rVefsrrV2L+kBFjPIWcO+Q0DYP76bTYFkIn3fdbRo1AdHQUomTQt6skyGUpeC0QSEG+nMj4= X-Received: by 2002:a25:cbc4:: with SMTP id b187mr4083159ybg.260.1600913154443; Wed, 23 Sep 2020 19:05:54 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Andrii Nakryiko Date: Wed, 23 Sep 2020 19:05:43 -0700 Message-ID: Subject: Re: flow_dissector test is flaky To: Alexei Starovoitov Cc: Stanislav Fomichev , bpf , Daniel Borkmann , Andrii Nakryiko , Muchun Song Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Wed, Sep 23, 2020 at 6:49 PM Alexei Starovoitov wrote: > > Hi Stanislav, > > looks like flow_dissector selftest got quite unstable recently. > test_link_update_invalid_opts:FAIL:340 > bpf_link_create(prog1): Argument list too long > #33/25 flow dissector link update invalid opts:FAIL > test_link_update_invalid_prog:FAIL:400 > bpf_link_create(prog1): Argument list too long > #33/26 flow dissector link update invalid prog:FAIL > #33/27 flow dissector link update netns gone:OK > I've seen similar flakiness for cgroup_link selftest that used to be rock solid. And it just clicked when I saw this, that this patch might be a culprit: https://patchwork.ozlabs.org/project/netdev/patch/20200917074453.20621-1-songmuchun@bytedance.com/ It makes bpf_link detachment delayed, so now anything that relies on the fact that bpf_link gets auto-detached immediately after the last link FD was closed is flaky. But that is a pretty reasonable and convenient assumption. So can we please revert that patch? It's a really nice guarantee to have, while the benefits of the fix in that patch is a bit ephemeral. > It's failing for me half of the time with a random number of failures. > Not sure what happened. I think it was stable in the past. > To reproduce: > test_progs -t flow_dissector