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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT 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 476BAC43142 for ; Mon, 25 Jun 2018 14:28:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 07A2025B6B for ; Mon, 25 Jun 2018 14:28:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 07A2025B6B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.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 S934406AbeFYO2C (ORCPT ); Mon, 25 Jun 2018 10:28:02 -0400 Received: from mx2.suse.de ([195.135.220.15]:58181 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934258AbeFYO2A (ORCPT ); Mon, 25 Jun 2018 10:28:00 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (charybdis-ext-too.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id C9814AD69; Mon, 25 Jun 2018 14:27:59 +0000 (UTC) Date: Mon, 25 Jun 2018 16:27:58 +0200 From: Petr Mladek To: Sergey Senozhatsky Cc: Maninder Singh , sergey.senozhatsky@gmail.com, rostedt@goodmis.org, linux-kernel@vger.kernel.org, a.sahrawat@samsung.com, pankaj.m@samsung.com, v.narang@samsung.com Subject: Re: [PATCH v2] printk: make sure to print log on console. Message-ID: <20180625142758.ourdvfid3aymgvan@pathway.suse.cz> References: <20180601090029epcas5p3cc93d4bfbebb3199f0a2684058da7e26~z-a_jkmrI2993329933epcas5p3q@epcas5p3.samsung.com> <20180618061550.GA27996@jagdpanzerIV> <20180618062306.GA29683@jagdpanzerIV> <20180619093244.ehj34uhpnpv6447f@pathway.suse.cz> <20180619094953.GB2631@jagdpanzerIV> <20180619105213.uzf6ba3oo3475icz@pathway.suse.cz> <20180620015525.GC650@jagdpanzerIV> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180620015525.GC650@jagdpanzerIV> User-Agent: NeoMutt/20170421 (1.8.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 2018-06-20 10:55:25, Sergey Senozhatsky wrote: > On (06/19/18 12:52), Petr Mladek wrote: > > > But when I set /sys/module/printk/parameters/ignore_loglevel I naturally > > > expect it to take an immediate action. Without waiting for the consoles > > > to catch up and to discard N messages [if the consoles were behind the > > > logbuf head]. > > > > Yeah, I understand this view. I thought about it as well. But did you > > ever needed this behavior in the real life? > > > > I personally changed ignore_loglevel only before I wanted to reproduce a > > bug. Then it would be perfectly fine to handle it only in > > vprintk_emit(). In fact, it would be even better because it would > > affect only messages that happened after I triggered the bug. > > So maybe the patch can stand the way it is, after all. JFI, still haven't > seen those "helps in real life a lot" examples, tho. I have personally seen these races when testing printk in NMI. I combined iptables logging, ping -f and sysrq-l. I am not sure how often they happen in the real life but I could understand that it might be annoying. This patch goes in the right direction and nobody really blocks it. Therefore I pushed it into printk.git, branch for-4.19. Best Regards, Petr