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From:   Masahiro Yamada <masahiroy@kernel.org>
Date:   Thu, 16 Nov 2023 20:23:37 +0900
Message-ID: <CAK7LNAR1i8HP8E3UmmSggZMka+UbJswU_bVMyxmRt4CbQhoTAA@mail.gmail.com>
Subject: Re: [PATCH][next] Makefile: Enable -Wstringop-overflow globally
To:     "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc:     Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nicolas Schier <nicolas@fjasle.eu>,
        linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org
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On Thu, Nov 16, 2023 at 12:27=E2=80=AFPM Gustavo A. R. Silva
<gustavoars@kernel.org> wrote:
>
> It seems that we have finished addressing all the remaining
> issues regarding compiler option -Wstringop-overflow. So, we
> are now in good shape to enable this compiler option globally.
>
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
>  Makefile                   | 3 +++
>  scripts/Makefile.extrawarn | 2 --
>  2 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index 690cde550acd..452b7d0e19e9 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -985,6 +985,9 @@ NOSTDINC_FLAGS +=3D -nostdinc
>  # perform bounds checking.
>  KBUILD_CFLAGS +=3D $(call cc-option, -fstrict-flex-arrays=3D3)
>
> +# We are now in good shape to enable this option.

Please remove this comment.

It it fine to mention it in the commit log, but
not in the Makefile.


I hope somebody will double-check this patch in CI infrastructure.


> +KBUILD_CFLAGS +=3D $(call cc-option, -Wstringop-overflow)
> +
>  # disable invalid "can't wrap" optimizations for signed / pointers
>  KBUILD_CFLAGS  +=3D -fno-strict-overflow
>
> diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
> index 2fe6f2828d37..1527199161d7 100644
> --- a/scripts/Makefile.extrawarn
> +++ b/scripts/Makefile.extrawarn
> @@ -106,7 +106,6 @@ KBUILD_CFLAGS +=3D $(call cc-option, -Wunused-const-v=
ariable)
>  KBUILD_CFLAGS +=3D $(call cc-option, -Wpacked-not-aligned)
>  KBUILD_CFLAGS +=3D $(call cc-option, -Wformat-overflow)
>  KBUILD_CFLAGS +=3D $(call cc-option, -Wformat-truncation)
> -KBUILD_CFLAGS +=3D $(call cc-option, -Wstringop-overflow)
>  KBUILD_CFLAGS +=3D $(call cc-option, -Wstringop-truncation)
>
>  KBUILD_CPPFLAGS +=3D -Wundef
> @@ -122,7 +121,6 @@ KBUILD_CFLAGS +=3D $(call cc-disable-warning, restric=
t)
>  KBUILD_CFLAGS +=3D $(call cc-disable-warning, packed-not-aligned)
>  KBUILD_CFLAGS +=3D $(call cc-disable-warning, format-overflow)
>  KBUILD_CFLAGS +=3D $(call cc-disable-warning, format-truncation)
> -KBUILD_CFLAGS +=3D $(call cc-disable-warning, stringop-overflow)
>  KBUILD_CFLAGS +=3D $(call cc-disable-warning, stringop-truncation)
>
>  ifdef CONFIG_CC_IS_CLANG
> --
> 2.34.1
>


--=20
Best Regards
Masahiro Yamada