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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 6BF8CC282E1 for ; Sat, 25 May 2019 00:56:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 47E1720863 for ; Sat, 25 May 2019 00:56:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726568AbfEYA4g (ORCPT ); Fri, 24 May 2019 20:56:36 -0400 Received: from smtprelay0086.hostedemail.com ([216.40.44.86]:32786 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726238AbfEYA4f (ORCPT ); Fri, 24 May 2019 20:56:35 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay02.hostedemail.com (Postfix) with ESMTP id 468474430; Sat, 25 May 2019 00:56:34 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: need28_735f329e4561a X-Filterd-Recvd-Size: 2467 Received: from XPS-9350.home (cpe-23-242-196-136.socal.res.rr.com [23.242.196.136]) (Authenticated sender: joe@perches.com) by omf01.hostedemail.com (Postfix) with ESMTPA; Sat, 25 May 2019 00:56:32 +0000 (UTC) Message-ID: <6b56ca73a5686513fc4ce9d3e07e402cfeeac544.camel@perches.com> Subject: Re: [PATCH] printk: Monitor change of console loglevel. From: Joe Perches To: Tetsuo Handa , Linus Torvalds Cc: Andrew Morton , Linux List Kernel Mailing , Dmitry Vyukov , Petr Mladek , Sergey Senozhatsky Date: Fri, 24 May 2019 17:56:31 -0700 In-Reply-To: References: <1557501546-10263-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.30.1-1build1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2019-05-25 at 09:14 +0900, Tetsuo Handa wrote: > On 2019/05/25 2:17, Linus Torvalds wrote: > > A config option or two that help syzbot doesn't sound like a bad idea to me. > > Thanks for suggestion. I think that #ifdef'ing > > static bool suppress_message_printing(int level) > { > return (level >= console_loglevel && !ignore_loglevel); > } > > is simpler. [] > On 2019/05/25 2:55, Linus Torvalds wrote: > > On Fri, May 24, 2019 at 10:41 AM Joe Perches wrote: > > > That could also help eliminate unnecessary pr_ output > > > from object code. > > > > Indeed. The small-config people might like it (if they haven't already > > given up..) > > Do you mean doing e.g. > > #define pr_debug(fmt, ...) no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__) > > depending on the minimal console loglevel kernel config option? Then, OK. Yes. Perhaps something like the below (or an equivalent generic wrapper) #define pr_info(fmt, ...) \ do { \ if (CONFIG_STATIC_CONSOLE_LEVEL >= LOGLEVEL_INFO) \ printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__); \ else \ no_printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__); \ } while (0) for each pr_, dev_ and netdev_