linux-kernel - Re: [greybus-dev] [PATCH] Kbuild: remove -std=gnu89 from compiler arguments

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Date:   Sun, 27 Feb 2022 15:11:41 -0800
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Alex Elder <elder@...aro.org>
Cc:     Arnd Bergmann <arnd@...nel.org>,
        Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
        Arnd Bergmann <arnd@...db.de>,
        Masahiro Yamada <masahiroy@...nel.org>, llvm@...ts.linux.dev,
        Jonathan Corbet <corbet@....net>,
        Federico Vaga <federico.vaga@...a.pv.it>,
        Alex Shi <alexs@...nel.org>, Hu Haowen <src.res@...il.cn>,
        Michal Marek <michal.lkml@...kovi.net>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        "open list:DOCUMENTATION" <linux-doc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-doc-tw-discuss@...ts.sourceforge.net,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        intel-gfx <intel-gfx@...ts.freedesktop.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        greybus-dev@...ts.linaro.org, linux-staging@...ts.linux.dev,
        linux-btrfs <linux-btrfs@...r.kernel.org>
Subject: Re: [greybus-dev] [PATCH] Kbuild: remove -std=gnu89 from compiler arguments

On Sun, Feb 27, 2022 at 3:04 PM Alex Elder <elder@...aro.org> wrote:
>
> Glancing at the Greybus code, I don't believe there's any
> reason it needs to shift a negative value.  Such warnings
> could be fixed by making certain variables unsigned, for
> example.

As mentioned in the original thread, making things unsigned actually
is likely to introduce bugs and make things worse.

The warning is simply bogus, and the fact that it was enabled by
-Wextra in gcc for std=gnu99 and up was a mistake that looks likely to
be fixed in gcc.

So don't try to "fix" the code to make any possible warnings go away.
You may just make things worse.

(That is often true in general for the more esoteric warnings, but in
this case it's just painfully more obvious).

              Linus