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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 01690C1B0F2 for ; Wed, 20 Jun 2018 09:09:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AEBB320652 for ; Wed, 20 Jun 2018 09:09:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jrXT04VS" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AEBB320652 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754702AbeFTJJ1 (ORCPT ); Wed, 20 Jun 2018 05:09:27 -0400 Received: from mail-pg0-f67.google.com ([74.125.83.67]:42497 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754765AbeFTJGo (ORCPT ); Wed, 20 Jun 2018 05:06:44 -0400 Received: by mail-pg0-f67.google.com with SMTP id c10-v6so1186580pgu.9 for ; Wed, 20 Jun 2018 02:06:43 -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=+zMJeLvg9M+qXEaAcahk8RwoZhePMjXySZrsTdVLp14=; b=jrXT04VS1wvJ4LtYWivbS8UabHga/4bEDYqXzuh8HIzRvJ+rZ3tB8GVoLmZEHgMZfd 4cj4ZNt8MZm+2F0OVVHYFnGbZWOkNV5kbLm/129lu3fhE2Y8+SD+Clnzaqw0MpwkbwSY yyWyGzEk1LjywecwdoTCHgI/5sRq519ewD3wYlP1X8dmMKHNw140DLUbFoswxr+V7OGT rgxgHn+cVKSexxyw1TDXwInSlodYbkdFk0CbB10zo0+fUQKVvpv87h/T/xS/oSMKI39w +jtqSeB6cH5y3ywrAD+PbhePhU14bbY38GDBJ03/DaLh74eavq8sFgDTEwKKgIOv/tYE f4iQ== 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=+zMJeLvg9M+qXEaAcahk8RwoZhePMjXySZrsTdVLp14=; b=IUzX1+30joYcta59P76wcBbgGgjlOl1Co7DtIBczIjbAcV2Xpcl8OJsvAg/nPthp0U qG7W9DZAg/2r+OVrfs528Uzh2ARj3yRkmoFPwT8A7yV5FCInN6dTtTrHUMiCZ6JIWql+ kgp9l9aVdEYUaesHez2no4xuovjiBLYQCIrZ9tAi/XdX8CXyUahXXMap9+YOnYDIMeDX 5E/E725E6WgIEtlR7U6LpN/icpCEobldAL2twwD5Z3Z/6cGqehcElufpGWcTa8g+pV7q ULuMGCaEuJ9gGF08XDnpVcB6ougDmwAXTS/08bchpOcsVFqn+ZZ0yq3wdNbn53083zJw xpFg== X-Gm-Message-State: APt69E0+OV6MZpzgHU7KEW+/BhcUiBRzXZWWlH9lEtWEHQsHpQjQueMO Jknr80XpBw8As6cgSDS6IUk= X-Google-Smtp-Source: ADUXVKKhKhWjP989zR1zohWTyAWD/ZqgwFH88MsVrAeQq+2AS7SFTXy8iYtjNVrO4X1YPCU6ngJA0A== X-Received: by 2002:a62:a8e:: with SMTP id 14-v6mr21732913pfk.57.1529485603580; Wed, 20 Jun 2018 02:06:43 -0700 (PDT) Received: from localhost ([110.70.59.159]) by smtp.gmail.com with ESMTPSA id t5-v6sm2682208pfh.32.2018.06.20.02.06.41 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 20 Jun 2018 02:06:42 -0700 (PDT) Date: Wed, 20 Jun 2018 18:06:39 +0900 From: Sergey Senozhatsky To: Dmitry Vyukov Cc: Sergey Senozhatsky , Petr Mladek , Tetsuo Handa , Sergey Senozhatsky , syzkaller , Steven Rostedt , Fengguang Wu , LKML , Linus Torvalds , Andrew Morton Subject: Re: [PATCH] printk: inject caller information into the body of message Message-ID: <20180620090413.GA444@jagdpanzerIV> References: <20180511095004.GA6575@jagdpanzerIV> <201805112058.AAB05258.HJQFFOMFOVtOSL@I-love.SAKURA.ne.jp> <20180517112135.GB20796@jagdpanzerIV> <20180518121506.wilixxkznbtskw34@pathway.suse.cz> <20180524021451.GA23443@jagdpanzerIV> <20180620083126.GA477@jagdpanzerIV> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dmitry, On (06/20/18 10:45), Dmitry Vyukov wrote: > Hi Sergey, > > What are the visible differences between this patch and Tetsuo's > patch? I guess none, and looking at your requirements below I tend to agree that Tetsuo's approach is probably what you need at the end of the day. > The only thing that will matter for syzkaller parsing in the > end is the resulting text format as it appears on console. But you say > "I'm not pushing for this particular message format", so what exactly > do you want me to provide feedback on? > I guess we need to handle pr_cont properly whatever approach we take. Mostly, was wondering about if: a) you need pr_cont() handling b) you need printk_safe() handling The reasons I left those things behind: a) pr_cont() is officially hated. It was never supposed to be used on SMP systems. So I wasn't sure if we need all that effort and add tricky code to handle pr_cont(). Given that syzkaller is probably the only user of that functionality. b) printk_safe output is quite uncommon. And we flush per-CPU buffer from the same CPU which has caused printk_safe output [except for panic() flush] therefore logging the info available to log_store() seemed enough. IOW, once again, was a bit unsure if we want to add some complex code to already complex code, with just one potential user. To summarize, I was just wondering where is the waterline: can a small patch make you happy, or do you need a big one. > Re format, for us it would be much more convenient if the context is a > single token that can be used as is, say "T" for task context, > "I" for interrupts, "N" for nmi's Got it. -ss