Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161020AbaDBWaS (ORCPT ); Wed, 2 Apr 2014 18:30:18 -0400 Received: from mail-ie0-f175.google.com ([209.85.223.175]:45469 "EHLO mail-ie0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030634AbaDBWaR (ORCPT ); Wed, 2 Apr 2014 18:30:17 -0400 Message-ID: <533C8F75.9000301@gmail.com> Date: Wed, 02 Apr 2014 15:30:13 -0700 From: David Daney User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: Mateusz Guzik CC: Steven Rostedt , LKML , Linus Torvalds , Andrew Morton , Thomas Gleixner , "H. Peter Anvin" , Borislav Petkov , Ingo Molnar , Mel Gorman , Kay Sievers Subject: Re: [RFC PATCH] cmdline: Hide "debug" from /proc/cmdline References: <20140402144219.4cafbe37@gandalf.local.home> <20140402221212.GD16570@mguzik.redhat.com> In-Reply-To: <20140402221212.GD16570@mguzik.redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/02/2014 03:12 PM, Mateusz Guzik wrote: > On Wed, Apr 02, 2014 at 02:42:19PM -0400, Steven Rostedt wrote: >> It has come to our attention that a system running a specific user >> space init program will not boot if you add "debug" to the kernel >> command line. What happens is that the user space tool parses the >> kernel command line, and if it sees "debug" it will spit out so much >> information that the system fails to boot. This basically renders the >> "debug" option for the kernel useless. >> >> This bug has been reported to the developers of said tool >> here: >> >> https://bugs.freedesktop.org/show_bug.cgi?id=76935 >> >> The response is: >> >> "Generic terms are generic, not the first user owns them." >> >> That is, the "debug" statement on the *kernel* command line is not >> owned by the kernel just because it was the first user of it, and >> they refuse to fix their bug. >> >> Well, my response is, we OWN the kernel command line, and as such, we >> can keep the users from seeing stuff on it if we so choose. And with >> that, I propose this patch, which hides "debug" from /proc/cmdline, >> such that we don't have to worry about tools parsing for it and causing >> hardship for those trying to debug the kernel. >> > > Well, parsing kernel cmdline by systemd is a bad idea, and hiding > "debug" is even worse. What will happen when the next keyword clashes? > And how should I check the kernel is booted with "debug"? > > If there is a real need to pass arguments to systemd, how about a > dedicated option (initargs= or whatever, where it has to be last in > cmdline), then systemd would be spawned with these arguments and would > just go over its argv. > What if systemd only parsed kernel command line arguments of the form: ... systemd.arg_foo systemd.arg_bar=x ... Then it wouldn't get confused by arguments that weren't directly targeted at it. There is precedence for this form, as it is what we already use for built-in modules. As a bonus, we would be ready for when systemd is integrated into the kernel as a module itself. Thanks, David Daney -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/