Re: [PATCH v2] init: Do not select DEBUG_KERNEL by default

From: Josh Triplett <josh@joshtriplett.org>
To: Kees Cook <keescook@chromium.org>
Cc: Sinan Kaya <okaya@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Masahiro Yamada <yamada.masahiro@socionext.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Nicholas Piggin <npiggin@gmail.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Vasily Gorbik <gor@linux.ibm.com>, Adrian Reber <adrian@lisas.de>,
	Richard Guy Briggs <rgb@redhat.com>,
	Petr Mladek <pmladek@suse.com>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Matthew Wilcox <willy@infradead.org>,
	Joe Lawrence <joe.lawrence@redhat.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	Mikulas Patocka <mpatocka@redhat.com>,
	Robin Murphy <robin.murphy@arm.com>,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	Changbin Du <changbin.du@intel.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Sam Ravnborg <sam@ravnborg.org>, Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH v2] init: Do not select DEBUG_KERNEL by default
Date: Wed, 10 Apr 2019 20:02:47 -0700	[thread overview]
Message-ID: <FF2E07CA-99D7-4F9C-B281-425897535C84@joshtriplett.org> (raw)
In-Reply-To: <CAGXu5jLc_Z=TiNsMd40GN8-0D117RVbdD7Hy4MzjPQNbFf=bcg@mail.gmail.com>

On April 10, 2019 4:24:18 PM PDT, Kees Cook <keescook@chromium.org> wrote:
>On Wed, Apr 10, 2019 at 4:22 PM Josh Triplett <josh@joshtriplett.org>
>wrote:
>>
>> On April 10, 2019 3:58:55 PM PDT, Kees Cook <keescook@chromium.org>
>wrote:
>> >On Wed, Apr 10, 2019 at 3:42 PM Sinan Kaya <okaya@kernel.org> wrote:
>> >>
>> >> We can't seem to have a kernel with CONFIG_EXPERT set but
>> >> CONFIG_DEBUG_KERNEL unset these days.
>> >>
>> >> While some of the features under the CONFIG_EXPERT require
>> >> CONFIG_DEBUG_KERNEL, it doesn't apply for all features.
>> >>
>> >> It looks like CONFIG_KALLSYMS_ALL is the only feature that
>> >> requires CONFIG_DEBUG_KERNEL.
>> >>
>> >> Select CONFIG_EXPERT when CONFIG_DEBUG is chosen but you can
>> >
>> >Typo: CONFIG_DEBUG_KERNEL
>> >
>> >> still choose CONFIG_EXPERT without CONFIG_DEBUG.
>> >
>> >same.
>> >
>> >>
>> >> Signed-off-by: Sinan Kaya <okaya@kernel.org>
>> >
>> >But with those fixed, looks good to me. Adding Josh (and others) to
>CC
>> >since he originally added the linkage to EXPERT in commit
>> >f505c553dbe2.
>>
>> CONFIG_DEBUG_KERNEL shouldn't affect code generation in any way; it
>should only make more options appear in kconfig. I originally added
>this to ensure that features you might want to *disable* aren't hidden,
>as part of the tinification effort.
>>
>> What specific problem does having CONFIG_DEBUG_KERNEL enabled cause
>for you? I'd still prefer to have a single switch for "don't hide
>things I might want to disable", rather than several.
>
>See earlier in the thread: code generation depends on
>CONFIG_DEBUG_KERNEL now unfortunately.

Then let's fix *that*, and get checkpatch to help enforce it in the future. EXPERT doesn't affect code generation, and neither should this.