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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Wed, 04 Apr 2018 16:53:52 +0000
Message-ID: <CAKwvOdmk-e5NCkyMT_LX2i5F1X+xGP+ZxAjaJasjgE6FaXKi6w@mail.gmail.com>
Subject: Re: [GIT PULL] x86/build changes for v4.17
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     Matthias Kaehlcke <mka@chromium.org>,
        Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        James Y Knight <jyknight@google.com>,
        Chandler Carruth <chandlerc@google.com>,
        Stephen Hines <srhines@google.com>,
        Kees Cook <keescook@google.com>, groeck@chromium.org,
        Greg Hackmann <ghackmann@google.com>
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On Wed, Apr 4, 2018 at 2:38 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> There are known-bugs with building a kernel with clang right now (I
> pointed one out a few days ago about NULL checks being deleted from the
> clang output for no good reason, which really is scary for obvious
> reasons).

Is this the thread you are referring to?
https://lkml.org/lkml/2018/3/27/1286

It's definitely something curious that I'll need to sit down and
investigate more.  If there are other known instances, it would be good to
let me know.

> So while it is great that small subsets of the kernel can
> work properly (or hopefully properly), with clang, it still isn't ready
> to be considered a "fully supported and we can't change the kernel if we
> break using it" option, sorry.

> And don't tie _anything_ to a LTS kernel, that's exactly what those
> kernels are NOT for.  You implement features and things in the kernel
> when they are ready, and I'll pick a random LTS kernel out of the air
> when I feel like it.  Never should the two intersect and matter.

> So please, work on fixing up clang for asm-goto and other "features"
> that the kernel requires, and maybe when all build options/configs are
> really solid and working well, will we be able to properly consider it
> as a reason to implement, or not implement, something in the kernel
> source.

Acknowledged.
-- 
Thanks,
~Nick Desaulniers