Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753422AbaJTVCH (ORCPT ); Mon, 20 Oct 2014 17:02:07 -0400 Received: from relay6-d.mail.gandi.net ([217.70.183.198]:43924 "EHLO relay6-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753211AbaJTVCE (ORCPT ); Mon, 20 Oct 2014 17:02:04 -0400 X-Originating-IP: 173.246.103.110 Date: Mon, 20 Oct 2014 14:01:55 -0700 From: Josh Triplett To: Andy Lutomirski Cc: Andrew Morton , Rob Landley , Frank Rowand , "linux-kernel@vger.kernel.org" , Chuck Ebbert , Randy Dunlap , Shuah Khan Subject: Re: [PATCH v5] init: Disable defaults if init= fails Message-ID: <20141020210155.GD29486@jtriplet-mobl1> References: <5c6381879bea68aebb13530442f1cf8a052be97f.1411958379.git.luto@amacapital.net> <542B4DA3.5080105@gmail.com> <542B519B.6010001@landley.net> <542B5E44.40303@gmail.com> <542B7200.6030902@landley.net> <20141001180510.GA28540@cloud> <20141014140052.2f114c158ffe6cd953020f1c@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 20, 2014 at 01:14:54PM -0700, Andy Lutomirski wrote: > On Tue, Oct 14, 2014 at 2:00 PM, Andrew Morton > wrote: > > On Wed, 1 Oct 2014 11:13:14 -0700 Andy Lutomirski wrote: > > > >> On Wed, Oct 1, 2014 at 11:05 AM, wrote: > >> > On Tue, Sep 30, 2014 at 09:53:56PM -0700, Andy Lutomirski wrote: > >> >> I significantly prefer default N. Scripts that play with init= really > >> >> don't want the fallback, and I can imagine contexts in which it could > >> >> be a security problem. > >> > > >> > While I certainly would prefer the non-fallback behavior for init as > >> > well, standard kernel practice has typically been to use "default y" for > >> > previously built-in features that become configurable. And I'd > >> > certainly prefer a compile-time configuration option like this (even > >> > with default y) over a "strictinit" kernel command-line option. > >> > > >> > >> Fair enough. > >> > >> So: "default y" for a release or two, then switch the default? Having > >> default y will annoy virtme, though it's not the end of the world. > >> Virtme is intended to work with more-or-less-normal kernels. > >> > > > > Adding another Kconfig option is tiresome. What was wrong with strictinit=? > > Now that this thread has gotten absurdly wrong, any thoughts? > > My preference order is: > > 1. The patch as is. > 2. The patch, minus the config option (i.e. making it unconditional). > 3. Something else. Agreed. > I would very much prefer to get *something* merged. The current > behavior is problematic for scripted kernel boots that don't use > initramfs. > > I can be flexible on the something else. One option would be to allow > a whole list of commands in init=, but that has compatibility issues. > Another would be adding an option like init_fallback=/bin/sh. A third > is the original strictinit mechanism. I don't really like any of > them, because they're all more complex. I agree, particularly because they *add* more logic rather than *removing* logic. In this case, I think a Kconfig option makes sense, because it controls additional behavior (the init fallback mechanism). Plus, adding more code to control init fallback at runtime then means I have more code to compile out to make the kernel smaller, so I'd end up adding that Kconfig option anyway. :) > IOW, the no-fallback behavior is easy to implement, easy to > understand, and has extremely predictable behavior. The fallback > behavior is more user friendly if you consider having a chance of > booting to something useful if you typo your init= option (but also a > chance of booting to something actively undesirable). Here's an alternative proposal: how about we change the default *without* a Kconfig option, see if anyone screams, and if they do, we add that code back in under a Kconfig option as in your current patch? Would that make your Kconfig senses stop tingling, Andrew? :) - Josh Triplett -- 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/