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From:   Kees Cook <keescook@chromium.org>
Date:   Mon, 9 Apr 2018 11:00:56 -0700
Message-ID: <CAGXu5jLSbX-qYx2xWYrsPb-tUFcEhYG86MkhtJ3zMirBHtmurg@mail.gmail.com>
Subject: Re: [bisected] 3c8ba0d61d04ced9f8d9ff93977995a9e4e96e91 oopses on s390
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Sebastian Ott <sebott@linux.ibm.com>,
        Sebastian Ott <sebott@linux.vnet.ibm.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
        Martin Uecker <Martin.Uecker@med.uni-goettingen.de>,
        Ingo Molnar <mingo@kernel.org>,
        Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
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On Mon, Apr 9, 2018 at 10:14 AM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
> On Mon, Apr 9, 2018 at 10:03 AM, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
>>
>> Our old "min()" had the internal variables called "min1" and "min2",
>> which is crazy too.
>
> Actually, no, it used the really cumbersome "__UNIQUE_ID" and then
> passed that odd as the name 'min1/2',
>
> Ugh, I find that really nasty to read, but it was obviously done
> because we hit this before.

Ooof. Nice find.

> And our __UNIQUE_ID() macro is garbage anyway, since it falls back on
> the line number, which doesn't really work for macros anyway. But we
> have proper macros for both clang and gcc, so maybe we should ignore
> the broken fallback.
>
> A patch like the attached, perhaps?

Can we update the comment near the top to explain why we need
__UNIQUE_ID() since we've now rediscovered why it was originally
there?

-Kees

-- 
Kees Cook
Pixel Security