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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 7A055C433DB for ; Tue, 5 Jan 2021 16:17:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 33E1820754 for ; Tue, 5 Jan 2021 16:17:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726020AbhAEQRy (ORCPT ); Tue, 5 Jan 2021 11:17:54 -0500 Received: from mx2.suse.de ([195.135.220.15]:40710 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725838AbhAEQRy (ORCPT ); Tue, 5 Jan 2021 11:17:54 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1609863428; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ZUxBRQYDloxPC81Kmm8jC5Exvkd9T5QGXBacWO+nHjY=; b=ZSbgk6dnmhPMwHjUaN4NVn5QAEdmFqmX/JkvKzlJiSkgcB8b92n3hT3920u8O5KMWMRs0C 5AI6wv5DHUN8wvfQCpytCNA9Ea5Yhw91A9JET6ASF7Hk+DM5l/MLD9GRTBDAfl6lJQMVFn uUByI6PfqxOGU6tB3HZkSQge+4q8Isw= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 00C32AA7C; Tue, 5 Jan 2021 16:17:07 +0000 (UTC) Date: Tue, 5 Jan 2021 17:17:07 +0100 From: Petr Mladek To: David Gow Cc: Andy Shevchenko , Shuah Khan , Brendan Higgins , KUnit Development , "open list:KERNEL SELFTEST FRAMEWORK" , Greg Kroah-Hartman , Guenter Roeck , Sergey Senozhatsky , Sergey Senozhatsky , linux-um Subject: Re: kunit stopped working Message-ID: References: <20201221144302.GR4077@smile.fi.intel.com> <20201221144510.GS4077@smile.fi.intel.com> <2d4b8148-48ca-290f-1d66-33e302e7571d@linuxfoundation.org> <20201221192757.GZ4077@smile.fi.intel.com> <20201221194008.GA4077@smile.fi.intel.com> <20201221200332.GB4077@smile.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On Tue 2020-12-22 09:43:48, David Gow wrote: > On Tue, Dec 22, 2020 at 4:02 AM Andy Shevchenko > wrote: > > > > On Mon, Dec 21, 2020 at 09:40:08PM +0200, Andy Shevchenko wrote: > > > +Cc people from culprit commit > > > > Guys, revert helps. I am open to test any solution you may propose, thanks! > > > > ... > > > > > # first bad commit: [757055ae8dedf5333af17b3b5b4b70ba9bc9da4e] init/console: Use ttynull as a fallback when there is no console > > > > -- > > +CC linux-um > > There appear to be two problems here: > 1. UML now no longer has console output by default (which KUnit needs > to get results) > This can be worked around for KUnit by passing console=tty to the > kernel. I don't think this is a "correct" fix It is rather a workaround. ttynull was supposed to be an ultimate fallback to provide a "valid" stdin, stdout, and stderr for the init process. ttyX still should be used by default when there is no console defined on the command line. So the question is why ttyX was not registered with this patch. I see the problem even when I revert the commit 757055ae8dedf5333af ("init/console: Use ttynull as a fallback when there is no console") and enable the ttynull driver as built in: CONFIG_NULL_TTY=y By other words, the problem existed even before. The commit only made it visible by default. I am still trying to understand arch/um and kunit code. I wonder if it is somehow related to stdiocons implemented in arch/um/drivers/stdio_console.c. Best Regards, Petr From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kwp1C-000853-6R for linux-um@lists.infradead.org; Tue, 05 Jan 2021 16:17:11 +0000 Date: Tue, 5 Jan 2021 17:17:07 +0100 From: Petr Mladek Subject: Re: kunit stopped working Message-ID: References: <20201221144302.GR4077@smile.fi.intel.com> <20201221144510.GS4077@smile.fi.intel.com> <2d4b8148-48ca-290f-1d66-33e302e7571d@linuxfoundation.org> <20201221192757.GZ4077@smile.fi.intel.com> <20201221194008.GA4077@smile.fi.intel.com> <20201221200332.GB4077@smile.fi.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: David Gow Cc: Sergey Senozhatsky , Greg Kroah-Hartman , Brendan Higgins , linux-um , Sergey Senozhatsky , "open list:KERNEL SELFTEST FRAMEWORK" , Shuah Khan , Andy Shevchenko , Guenter Roeck , KUnit Development On Tue 2020-12-22 09:43:48, David Gow wrote: > On Tue, Dec 22, 2020 at 4:02 AM Andy Shevchenko > wrote: > > > > On Mon, Dec 21, 2020 at 09:40:08PM +0200, Andy Shevchenko wrote: > > > +Cc people from culprit commit > > > > Guys, revert helps. I am open to test any solution you may propose, thanks! > > > > ... > > > > > # first bad commit: [757055ae8dedf5333af17b3b5b4b70ba9bc9da4e] init/console: Use ttynull as a fallback when there is no console > > > > -- > > +CC linux-um > > There appear to be two problems here: > 1. UML now no longer has console output by default (which KUnit needs > to get results) > This can be worked around for KUnit by passing console=tty to the > kernel. I don't think this is a "correct" fix It is rather a workaround. ttynull was supposed to be an ultimate fallback to provide a "valid" stdin, stdout, and stderr for the init process. ttyX still should be used by default when there is no console defined on the command line. So the question is why ttyX was not registered with this patch. I see the problem even when I revert the commit 757055ae8dedf5333af ("init/console: Use ttynull as a fallback when there is no console") and enable the ttynull driver as built in: CONFIG_NULL_TTY=y By other words, the problem existed even before. The commit only made it visible by default. I am still trying to understand arch/um and kunit code. I wonder if it is somehow related to stdiocons implemented in arch/um/drivers/stdio_console.c. Best Regards, Petr _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um