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Date:   Wed, 4 Apr 2018 18:59:14 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Nick Desaulniers <ndesaulniers@google.com>
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>
Subject: Re: [GIT PULL] x86/build changes for v4.17
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On Wed, Apr 04, 2018 at 04:53:52PM +0000, Nick Desaulniers wrote:
> (re-sending as plain text)
> 
> 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.

Here is another horrible work around that was needed to get clang to
stop generating invalid code, beaec533fc27 ("llist: clang: introduce
member_address_is_nonnull()")  That one caused a lot of odd failures by
users, I wonder what else is lurking in that same code pattern.  It's a
hard one to debug...

thanks,

greg k-h