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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Tue, 7 Sep 2021 12:16:22 -0700
Message-ID: <CAHk-=whJOxDefgSA1_ojGbweRJGonWX9_nihA-=fbXFV1DhuxQ@mail.gmail.com>
Subject: Re: [PATCH] Revert "Enable '-Werror' by default for all kernel builds"
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     llvm@lists.linux.dev,
        LSM List <linux-security-module@vger.kernel.org>,
        linux-toolchains@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Kees Cook <keescook@chromium.org>,
        Mark Brown <broonie@kernel.org>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Michal Marek <michal.lkml@markovi.net>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vipin Sharma <vipinsh@google.com>,
        Chris Down <chris@chrisdown.name>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Vlastimil Babka <vbabka@suse.cz>,
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On Tue, Sep 7, 2021 at 11:39 AM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> The above commit seems as though it was merged in response to
> https://lore.kernel.org/linux-hardening/CAHk-=wj4EG=kCOaqyPEq5VXa97kyUHsBpBn3DWwE91qcnDytOQ@mail.gmail.com/.

No. It was merged in response of _years_ of pain, with the last one
just being the final drop.

I'm not going to revert that change. I probably will have to limit it
(by making that WERROR option depend on certain expectations), but
basically any maintainer who has code that causes warnings should
expect that they will have to fix those warnings.

If it's clang that generates bogus warnings, then we'll have to start
disable clang warnings. The clang people tend to be proud of thir
fewer false positives, but so far looking at things, I am not
convinced.

And I'm most definitely not convinced when the "let's finally enable
-Werror after years of talking about it", people end up going "but but
but I have thousands of warnings".

That's the POINT of that commit. That "but but but I have thousands of
warnings" is not acceptable.

I spent hours yesterday getting rid of some warnings. It shouldn't be
on me fixing peoples code. It shouldn't be on me noticing that people
send me crap that warns.

And it really shouldn't be "Linus cares about warnings, so
configurations that Linus doesn't test can continue for years to have
them".

My "no warnings" policy isn't exactly new, and people shouldn't be
shocked when I then say "time to clean up *YOUR* house too".

            Linus