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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT 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 B3521C31E46 for ; Wed, 12 Jun 2019 08:36:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 895532063F for ; Wed, 12 Jun 2019 08:36:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="RgqTRH6Y" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405539AbfFLIgs (ORCPT ); Wed, 12 Jun 2019 04:36:48 -0400 Received: from mail-pf1-f179.google.com ([209.85.210.179]:46477 "EHLO mail-pf1-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727027AbfFLIgs (ORCPT ); Wed, 12 Jun 2019 04:36:48 -0400 Received: by mail-pf1-f179.google.com with SMTP id 81so9209909pfy.13 for ; Wed, 12 Jun 2019 01:36:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=8D1H9g9GFlDAss1Xnkrc39q7LIlBQcRGRBG+sL7YE+8=; b=RgqTRH6YlgD0ehcaP2t9921mgwMTGy0dMyAIYO334+o/hCfcrYwM9VU/JuXUrLJGKr qWT1RCDAicYs1zLhcPqE93E01O+swZZKRoI2mNGKq7c8KCH+4++5jViDywzBwJiyVhNr 6vkfXVe1IPObhQcBumxID6Gx+QWLM/6NOIqMQmcNyEy7FvOJTwRwVCsJRX+FDsSzAtGH tb0r5m3UhefZy/L4H+AwUZxNd+mZKR7CFHM6hnYKjZcdThYtZOm8ohRRJpxUC/3VhUOx 6sk+WmIQv9VXjKtwOBn3vHvNaSfS87sjv0mGvQS2ym4frKsKOTsGo0c/r0z7pLBMt+/j 3a1g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=8D1H9g9GFlDAss1Xnkrc39q7LIlBQcRGRBG+sL7YE+8=; b=dwOmcVnsRfrTKuKPz3No+z+RzaTWVvtDQ/lMygUXDA3Sdq3tx+Q8JaG0SvgPJ8RKni Yk6pOYyM5j4u2em+e3bYix+dXdtUw0JN4gODb5Q12TFXA2VVHEmJHFicIPho/5pc+VK+ /RPKeFH1Gq7nrEvlkqkdNrdmfop5uZmBio2yR0QNMG+wNLKSwbqR1mUFlvOVxqshBj30 SAl0ALNLIcwhMteUOv4QWOUhBRrrxwwBnewKEBAFCkY9gdro1Pi/xz8k0ZdRlEPNttr6 0ewap4c1+qibGM312NElZe60UfC0HaW94tBKtDPs22TIw8cG1BGhJwbdO6b2502xiu21 es/w== X-Gm-Message-State: APjAAAVqsvoV/biYPqomAodGArhtBOCXnpGdeIP5sL2D/E0TstSd90or HEN2TW7DSPRrFIjRvhhstPk= X-Google-Smtp-Source: APXvYqyogKFHc9PXyY1nt+pPC0hhqK4zNvLOmK+YUKnbR74u2S3xRVOg9Tu5agL7aepUJrsZ+gK+lw== X-Received: by 2002:a17:90a:1b0c:: with SMTP id q12mr31843718pjq.76.1560328607531; Wed, 12 Jun 2019 01:36:47 -0700 (PDT) Received: from localhost ([110.70.55.193]) by smtp.gmail.com with ESMTPSA id r11sm15330567pgs.39.2019.06.12.01.36.45 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Wed, 12 Jun 2019 01:36:46 -0700 (PDT) Date: Wed, 12 Jun 2019 17:36:43 +0900 From: Sergey Senozhatsky To: Petr Mladek Cc: Sergey Senozhatsky , Dmitry Safonov , linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Jiri Slaby , Sergey Senozhatsky , Steven Rostedt , Tetsuo Handa Subject: Re: [RFC] printk/sysrq: Don't play with console_loglevel Message-ID: <20190612083643.GA7722@jagdpanzerIV> References: <20190528002412.1625-1-dima@arista.com> <20190528041500.GB26865@jagdpanzerIV> <20190528044619.GA3429@jagdpanzerIV> <20190528134227.xyb3622gjwu52q4r@pathway.suse.cz> <20190603065153.GA13072@jagdpanzerIV> <20190606071039.txqczrjlntrljlrx@pathway.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190606071039.txqczrjlntrljlrx@pathway.suse.cz> User-Agent: Mutt/1.12.0 (2019-05-25) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (06/06/19 09:10), Petr Mladek wrote: > > > > > > Provide KERN_UNSUPPRESSED printk() annotation for such legacy places. > > > > > > Make sysrq print the headers unsuppressed instead of changing > > > > > > console_loglevel. > > > > > > I like this idea. console_loglevel is temporary manipulated only > > > when some messages should or should never appear on the console. > > > Storing this information in the message flags would help > > > to solve all the related races. > > > > I don't really like the whole system-wide console_loglevel manipulation > > thing, > > Just to be sure. I wanted to say that I like the idea with > KERN_UNSUPRESSED. So, I think that we are on the same page. I understand. All I wanted to say is that KERN_UNSUPRESSED is per-message, while the most interesting (and actually broken) cases, IMHO, are per-context, IOW things like this one console_loglevel = NEW foo() dump_stack() printk ... printk console_loglevel = OLD KERN_UNSUPRESSED does not help here. We probably can't convert dump_stack() to KERN_UNSUPRESSED. [..] > Now, KERN_EMERG might alarm some monitor of console output. It might > trigger unwanted reaction (forced reboot?) of the monitoring system > even when sysrq was not called in emergency situation. > > I am sure that we need to care about such monitors. I have to > think more about it. Sure. -ss