linux-kernel - Re: [PATCH v5] init: Disable defaults if init= fails

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Date:	Tue, 14 Oct 2014 23:37:28 -0700
From:	Frank Rowand <frowand.list@...il.com>
To:	Andy Lutomirski <luto@...capital.net>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	Josh Triplett <josh@...htriplett.org>,
	Rob Landley <rob@...dley.net>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Chuck Ebbert <cebbert.lkml@...il.com>,
	Randy Dunlap <rdunlap@...radead.org>,
	Shuah Khan <shuah.kh@...sung.com>
Subject: Re: [PATCH v5] init: Disable defaults if init= fails

On 10/14/2014 10:56 PM, Andy Lutomirski wrote:
> On Tue, Oct 14, 2014 at 10:46 PM, Frank Rowand <frowand.list@...il.com> wrote:
>> On 10/14/2014 2:21 PM, Andy Lutomirski wrote:
>>> On Tue, Oct 14, 2014 at 2:00 PM, Andrew Morton
>>> <akpm@...ux-foundation.org> wrote:
>>>> On Wed, 1 Oct 2014 11:13:14 -0700 Andy Lutomirski <luto@...capital.net> wrote:
>>>>
>>>>> On Wed, Oct 1, 2014 at 11:05 AM,  <josh@...htriplett.org> 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=?
>>>
>>> The consensus seems to be that adding a non-default option to get
>>
>>       ^^^^^^^^^  I do not think you know what the word consensus means. :-)
>>
>> I did not agree.
>>
>> I do agree with Andrew (but with no opinion on whether "strictinit=SOMETHING"
>> or just "strictinit".
>>
>>> sensible behavior would be unfortunate.  Also, I don't like
> 
> Even you're not disagreeing that it's ugly, though, FWIW.

You are putting (lack of) words in my mouth.  I did not comment on
"ugly" because it did not seem that big a deal to me.  I have no
desire to bikeshed on ugly in this particular instance.

> 
>>   ^^^^^^^^^^^^^^^^^
>>   behavior that is useful in some or many contexts
> 
> Is there a context in which the current behavior is useful beyond
> "whoops, I typoed my grub command line edit, and I still want my
> system to boot into *something* even if it's the wrong thing"?  I'm
> not personally that sympathetic to that particular use case, but maybe
> there's another one.

We've been through this before.  I should have ignored your "sensible
behavior" comment.  Sorry, again no need for me to bike shed on that.

The question from Andrew was whether to use a config option or a command
line option.  One could choose either behavior as default, whether
controlled by command line or config option.


> 
> --Andy
> 
>>
>>> strictinit=, since backwards-compatible setups will have to do
>>> init=foo strictinit=foo.  My original proposal was init=foo
>>> strictinit.
>>>
>>> TBH, my preference would be to make strict mode unconditional.
>>> http://xkcd.com/1172/
>>>
>>> --Andy

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