Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964819AbcDYTyk (ORCPT ); Mon, 25 Apr 2016 15:54:40 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:55098 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933458AbcDYTyj (ORCPT ); Mon, 25 Apr 2016 15:54:39 -0400 Date: Mon, 25 Apr 2016 12:54:37 -0700 From: Greg Kroah-Hartman To: Peter Zijlstra Cc: Steven Rostedt , Linus Torvalds , LKML , Ingo Molnar , Borislav Petkov , Andrew Morton , Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Subject: Re: [PATCH v2] printk: Add kernel parameter to disable writes to /dev/kmsg Message-ID: <20160425195437.GA25465@kroah.com> References: <20160425145606.598329f2@gandalf.local.home> <20160425190651.GL3448@twins.programming.kicks-ass.net> <20160425191815.GA24761@kroah.com> <20160425192435.GM3430@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160425192435.GM3430@twins.programming.kicks-ass.net> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1066 Lines: 25 On Mon, Apr 25, 2016 at 09:24:35PM +0200, Peter Zijlstra wrote: > On Mon, Apr 25, 2016 at 12:18:15PM -0700, Greg Kroah-Hartman wrote: > > On Mon, Apr 25, 2016 at 09:06:51PM +0200, Peter Zijlstra wrote: > > > On Mon, Apr 25, 2016 at 02:56:06PM -0400, Steven Rostedt wrote: > > > > +static bool __read_mostly devkmsg_disabled; > > > > +static int __init disable_devkmsg(char *str) > > > > +{ > > > > + devkmsg_disabled = true; > > > > + return 0; > > > > +} > > > > +__setup("printk.disable_kmsg_write", disable_devkmsg); > > > > > > Again, please default enable and use an easier name to toggle this. > > > Userspace flooding this with junk is really insane. > > > > If you default enable, you break working systems today that want to log > > stuff through this interface, sorry. > > Oh, you mean those 'working' systems that livelocked my box because I > had console to serial enabled which could not keep up with the endless > flood of shite? > > This systemd exposure has seriously eroded your sanity. See Andrew's message, this was added because of klibc :)