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=-23.6 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 9A260C433E0 for ; Wed, 6 Jan 2021 04:30:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4813122D71 for ; Wed, 6 Jan 2021 04:30:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726830AbhAFEaG (ORCPT ); Tue, 5 Jan 2021 23:30:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725996AbhAFEaG (ORCPT ); Tue, 5 Jan 2021 23:30:06 -0500 Received: from mail-lf1-x12e.google.com (mail-lf1-x12e.google.com [IPv6:2a00:1450:4864:20::12e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B7FC5C06134D for ; Tue, 5 Jan 2021 20:29:25 -0800 (PST) Received: by mail-lf1-x12e.google.com with SMTP id s26so3711603lfc.8 for ; Tue, 05 Jan 2021 20:29:25 -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=KGZhC2xpsnbKpiPKTbZzapmNsqmvVzf26wtQMSLPyWQ=; b=WmbMaBma2vnpsj9xAF30KVT18cCjMeLuG7vfriPQMmwK8sB0MvVJ4z4RPVS97rpY4z gmREnPnEA2NkXFxS4U69YgtlUmEHfQEQ5HAvevDdoDukSuxkQZ16FZK6DIXAsb+5o+Co mtzgFQj29uh6YiekvBcMW/sAULb6CcBFpTN859M5KykxkGos9f/I0UyPRBs45+1pe81t 5QbXH75MeTlMT3E9/5EAwouwjUPsWTTiv+xZH/ErBifwWwi3m3ba1f3BQkaI7ENlC3gm 3+0wjJpbJKlOtCVU6sM+4nbegwDbImIucxGnJtgIHyohFs/LXgbLufB1ZrCpS9RwnWqC mZLw== 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=KGZhC2xpsnbKpiPKTbZzapmNsqmvVzf26wtQMSLPyWQ=; b=PJuxrEmMGR/1zht4/uX4jGrp6NxUvviEkfRiHp5PyVkGMZgEayT4VUGuZx6m2QnrSS LAcDQAoMWukuU74VaDsb/0Ixv99Di7AVpRbe828ZUbOTJV08J73c9QU6+gNPgwSl/u15 xrvvx5o8S2KuJdzEv1k8ApDSXX5vf1krv2bmaqXoyGFsoSL2rt99XB/oPV72oFxbgzFP bfCpYo/iVxDZja6KWBRZ8D4GjO2pxz9BAjmE7L6C3ggaf+8NKFLd3Z0ma42p8+K1U4F7 BSuIIF2uyAA4KxaJPor0VvHlPW+0VfzYeinLwwlK6c0Bw5oNArzhyT8EL9RG2Rb7An2i llSA== X-Gm-Message-State: AOAM530ldjj+dB+edzWC29SHRnavc8rYHhDDph6yuwWwY8tX1Ak0g6Qe W3Xhag0ewPbzdQPPlVxuKzsEoTXliGxOS1qFm1JUXQ== X-Google-Smtp-Source: ABdhPJx736G6yw9RZc8ju06zfmwq/PVcFsrW7WQukA6RjbAHMDNBIk36nt1cDn2TEDsJkiGoWrv97NeWbUJBA2V4aPk= X-Received: by 2002:ac2:46cf:: with SMTP id p15mr1079796lfo.628.1609907364076; Tue, 05 Jan 2021 20:29:24 -0800 (PST) MIME-Version: 1.0 References: <20201222073900.3490607-1-davidgow@google.com> <20201222111102.GC4077@smile.fi.intel.com> <4ae7779c-15c5-0474-5840-44531dcf1d94@linuxfoundation.org> <3828c7ee-52b0-42f9-5771-74ef9386756c@linuxfoundation.org> <20210105185731.GT4077@smile.fi.intel.com> <918b2d05-f51b-0866-89b3-19a016abdaa3@linuxfoundation.org> In-Reply-To: <918b2d05-f51b-0866-89b3-19a016abdaa3@linuxfoundation.org> From: David Gow Date: Wed, 6 Jan 2021 12:29:12 +0800 Message-ID: Subject: Re: [PATCH] kunit: tool: Force the use of the 'tty' console for UML To: Shuah Khan Cc: Andy Shevchenko , Petr Mladek , Brendan Higgins , Senozhatsky , Sergey Senozhatsky , "open list:KERNEL SELFTEST FRAMEWORK" , KUnit Development , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 6, 2021 at 3:52 AM Shuah Khan wrote: > > On 1/5/21 11:57 AM, Andy Shevchenko wrote: > > On Tue, Jan 05, 2021 at 09:34:33AM -0700, Shuah Khan wrote: > >> On 1/5/21 9:21 AM, Petr Mladek wrote: > >>> On Mon 2021-01-04 09:23:57, Shuah Khan wrote: > >>>> On 12/22/20 4:11 AM, Andy Shevchenko wrote: > >>>>> On Mon, Dec 21, 2020 at 11:39:00PM -0800, David Gow wrote: > >>>>>> kunit_tool relies on the UML console outputting printk() output to the > >>>>>> tty in order to get results. Since the default console driver could > >>>>>> change, pass 'console=tty' to the kernel. > >>>>>> > >>>>>> This is triggered by a change[1] to use ttynull as a fallback console > >>>>>> driver which -- by chance or by design -- seems to have changed the > >>>>>> default console output on UML, breaking kunit_tool. While this may be > >>>>>> fixed, we should be less fragile to such changes in the default. > >>>>>> > >>>>>> [1]: > >>>>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=757055ae8dedf5333af17b3b5b4b70ba9bc9da4e > >>>>> > >>>>> Reported-by: Andy Shevchenko > >>>>> Tested-by: Andy Shevchenko > >>>>> > >>>> > >>>> Thank you all. Now in linux-kselftest kunit-fixes branch. > >>>> > >>>> Will send this up for rc3. > >>>> > >>>> Sorry for the delay - have been away from the keyboard for a > >>>> bit. > >>> > >>> JFYI, I am not sure that this is the right solution. I am > >>> looking into it, see > >>> https://lore.kernel.org/linux-kselftest/X%2FSRA1P8t+ONZFKb@alley/ > >>> for more details. > >>> > >> > >> Thanks Petr. I will hold off on sending the patch up to Linus and > >> let you find a the right solution. > > > > Please. leave it in Linux Next at least. Otherwise kunit will be broken for a > > long time which is not good. > > > > > > Yes. That is the plan. It will be in there until real fix comes in. > Thanks, Shuah. Personally, I think that this patch makes some sense to keep even if the underlying issue with ttynull is resolved. Given that kunit.py requires the console output, explicitly stating we want console=tty set is probably worth doing rather than relying on it being the default. That being said, I definitely agree that this patch doesn't fix the underlying issue with UML/ttynull: it just makes the kunit.py script less sensitive to such changes (which, while unlikely, could potentially occur legitimately down the track). Cheers, -- David