Re: [PATCH v5 1/3] Provide in-kernel headers to make extending kernel easier

From: Karim Yaghmour <karim.yaghmour@opersys.com>
To: Joel Fernandes <joel@joelfernandes.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Kees Cook <keescook@chromium.org>,
	Olof Johansson <olof@lixom.net>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Joel Fernandes <joelaf@google.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Qais Yousef <qais.yousef@arm.com>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Manoj Rao <linux@manojrajarao.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Alexei Starovoitov <ast@kernel.org>,
	atish patra <atishp04@gmail.com>,
	Daniel Colascione <dancol@google.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Guenter Roeck <groeck@chromium.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Android Kernel Team <kernel-team@android.com>,
	"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
	"open list:KERNEL SELFTEST FRAMEWORK" 
	<linux-kselftest@vger.kernel.org>,
	linux-trace-devel@vger.kernel.org,
	Masahiro Yamada <yamada.masahiro@socionext.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	Shuah Khan <shuah@kernel.org>, Yonghong Song <yhs@fb.com>
Subject: Re: [PATCH v5 1/3] Provide in-kernel headers to make extending kernel easier
Date: Tue, 16 Apr 2019 09:32:37 -0400	[thread overview]
Message-ID: <f8b15e31-1aab-ab2c-d44d-47325faab67d@opersys.com> (raw)
In-Reply-To: <20190416130440.GA7944@localhost>

On 4/16/19 9:04 AM, Joel Fernandes wrote:
> On Tue, Apr 16, 2019 at 02:49:39PM +0200, Greg Kroah-Hartman wrote:
>> On Tue, Apr 16, 2019 at 08:33:06AM -0400, Steven Rostedt wrote:
>>> On Mon, 15 Apr 2019 22:50:10 -0500
>>> Kees Cook <keescook@chromium.org> wrote:
>>>
>>>> On Mon, Apr 15, 2019 at 9:41 AM Steven Rostedt <rostedt@goodmis.org> wrote:
>>>>> I agree with this assessment. We shouldn't use config.gz as precedence
>>>>> for this solution. config.gz should have been in debugfs to begin with,
>>>>> but I don't believe debugfs was around when config.gz was introduced.
>>>>> (Don't have time to look into the history of the two).
>>>>
>>>> I don't agree with this: /proc/config.gz is used by a lot of tools
>>>> that do sanity-check of running systems. This isn't _debugging_...
>>>> it's verifying correct kernel builds. It's a fancy version of checking
>>>> /proc/version.
>>>>
>>>
>>> Then we should perhaps make a new file system call tarballs ;-)
>>>
>>>   /sys/kernel/tarballs/
>>>
>>> and place everything there. That way it removes it from /proc (which is
>>> the worse place for that) and also makes it something other than debug.
>>> That's what I did for tracefs.
>>
>> As horrible as that suggestion is, it does kind of make sense :)
>>
>> We can't put this in debugfs as that's only for debugging and systems
>> should never have that mounted for normal operations (users want to
>> build ebpf programs), and /proc really should be for processes but that
>> horse is long left the barn.
>>
>> But, I'm willing to consider putting this either in a system-fs-like
>> filesystem, or just in sysfs itself, we do have /sys/kernel/ to play
>> around in if the main objection is that we should not be cluttering up
>> /proc with stuff like this.
>>
> 
> I am ok with the suggestion of /sys/kernel for the archive. That also seems
> to fit well with the idea that the headers are kernel related and probably
> belong here more strictly speaking, than /proc.

This makes sense. And if it alleviates concerns regarding extending 
/proc ABIs then might as well switch to this.

Olof, what do you think of this?

-- 
Karim Yaghmour
CEO - Opersys inc. / www.opersys.com
http://twitter.com/karimyaghmour