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 90DCAC4363D for ; Thu, 24 Sep 2020 02:21:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3D0A921D20 for ; Thu, 24 Sep 2020 02:21:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="eVXtRIAp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726344AbgIXCVv (ORCPT ); Wed, 23 Sep 2020 22:21:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58538 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726281AbgIXCVv (ORCPT ); Wed, 23 Sep 2020 22:21:51 -0400 Received: from mail-lj1-x22a.google.com (mail-lj1-x22a.google.com [IPv6:2a00:1450:4864:20::22a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2AD20C0613CE for ; Wed, 23 Sep 2020 19:21:51 -0700 (PDT) Received: by mail-lj1-x22a.google.com with SMTP id u4so1323716ljd.10 for ; Wed, 23 Sep 2020 19:21:51 -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=2dYGDT/hLEmyYcsDvNE8TWjcD7Gh+AEYN2sgARYeMUI=; b=eVXtRIApWRCdVZXgYLGH2lgnXpLF6g0mHVITCEPqAgUIMfvcflbwfoxN3JUt7pyflG XGqoEE9TilY/ti6uxyL2iszcSmlo/bICKT8NLaKw823B3gLKlQgHxy8UMzdPkCLZXviB 2U35Riiv6QslNIiIB9pZrE6Rxzb+cwXB0+rIn3uOlnUX72BQr+xoDxE7WXWLc7G7VEep bEo7+mG5QOAH1pKxumIx+rXK23HX7SWAv9jN5FaLc+/65V7SAjtW+EY/D+eaVoqygy8h cVRTk00EeylCeRa9mOTgZncqjc7rmIArs4PzhdMOXA0BXCp1IXEH6rhTP0ObpWKYlm9R drsw== 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=2dYGDT/hLEmyYcsDvNE8TWjcD7Gh+AEYN2sgARYeMUI=; b=eIjGesAhBe+FCTrGnniLo/9njtxIT91T6EapAL9sa9c2J6WzOSQjJJcmJiP1X3mNBv UoihheL8oqJw7c4fa45cQEYTR/vXRxiXlAB55wCH+IlO+pOrIe1ITGu+e9fUDAqZ0aZ8 NH0aZKkWakD7ornAGVQPuuT1Llf2LBE9kJo8era6UEm87NZJk+6jYe996QprtdzlnAJ1 rc95CWq9sJxQ5CVUiFoAVdQVsklqYof2F0aJoj3pqfuC1FJlxCPLruprExCRl2xlyFbU 0Q/ct1NzyDDnbX00qasAjz+XUE7UcbD6cEyG4H81hccmsF58glri9ddwfRi29z1tfhb4 fC+Q== X-Gm-Message-State: AOAM5308GQMbFLFH+OhjLDRB6mTaotpwZMSt2QVy5Ox3S/K2EFAl9fXX uyYwFFptwulbuOftnzVtn52m4lFBpVADVcSdQTc= X-Google-Smtp-Source: ABdhPJxumtdRlD+lkPUGkQzRgk9puL8NLcVU0h+aoQlMq4XMb7OM1NcBIzJTjrvLcoYdHTBt8g70MWzZHNjBG+SwDDw= X-Received: by 2002:a2e:8593:: with SMTP id b19mr769935lji.290.1600914109254; Wed, 23 Sep 2020 19:21:49 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Alexei Starovoitov Date: Wed, 23 Sep 2020 19:21:38 -0700 Message-ID: Subject: Re: flow_dissector test is flaky To: Andrii Nakryiko 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 7:05 PM Andrii Nakryiko wrote: > > 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. Indeed. Reverted. The usage of in_atomic() is fine there.