Re: [PATCH] make CONFIG_EXPERIMENTAL invisible and default

[Kees Cook]

On Wed, Oct 3, 2012 at 9:47 AM, Paul E. McKenney
<paulmck@xxxxxxxxxxxxxxxxxx> wrote:
> On Wed, Oct 03, 2012 at 09:17:02AM -0700, Greg Kroah-Hartman wrote:
>> On Wed, Oct 03, 2012 at 06:25:38AM -0700, Paul E. McKenney wrote:
>> > On Tue, Oct 02, 2012 at 12:50:42PM -0700, Kees Cook wrote:
>> > > This config item has not carried much meaning for a while now and is
>> > > almost always enabled by default. As agreed during the Linux kernel
>> > > summit, it should be removed. As a first step, remove it from being
>> > > listed, and default it to on. Once it has been removed from all
>> > > subsystem Kconfigs, it will be dropped entirely.
>> > >
>> > > CC: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
>> > > CC: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
>> > > CC: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
>> > > CC: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
>> > > CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>> > > CC: Frederic Weisbecker <fweisbec@xxxxxxxxx>
>> > > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
>> > > ---
>> > >
>> > > This is the first of a series of 202 patches removing EXPERIMENTAL from
>> > > all the Kconfigs in the tree. Should I send them all to lkml (with all
>> > > the associated CCs), or do people want to cherry-pick changes from my
>> > > tree? I don't want to needlessly flood the list.
>> > >
>> > > http://git.kernel.org/?p=linux/kernel/git/kees/linux.git;a=shortlog;h=refs/heads/experimental
>> > >
>> > > I figure this patch can stand alone to at least make EXPERIMENTAL go
>> > > away from the menus, and give us a taste of what the removal would do
>> > > to builds.
>> >
>> > OK, I will bite...  How should I flag an option that is initially only
>> > intended for those willing to take some level of risk?
>>
>> In the text say "You really don't want to enable this option, use at
>> your own risk!"  Or something like that :)
>
> OK, so the only real hope for experimental features is to refrain from
> creating a config option for them, so that people wishing to use them
> must modify the code?  Or is the philosophy that we keep things out of
> tree until we are comfortable with distros turning them on?

I would expect a simple addition of "this is dangerous/buggy" to the
description and "default n" is likely the way to go for that kind of
thing. I think the history of CONFIG_EXPERIMENTAL has proven there
isn't a sensible way to create a global flag for this kind of thing.
To paraphrase Serge: my experimental options are not your experimental
options.

For example, some of the things that already had the experimental
config removed, they left the "(EXPERIMENTAL)" in their config title.

-Kees

-- 
Kees Cook
Chrome OS Security
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