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From:   Masahiro Yamada <yamada.masahiro@socionext.com>
Date:   Fri, 4 May 2018 23:21:51 +0900
Message-ID: <CAK7LNATV==PWHd2M63X+SMchRoTqtbnnSFSZM1bQnjCRfRrRKg@mail.gmail.com>
Subject: Re: [PATCH 01/30] gcc-plugins: fix build condition of SANCOV plugin
To:     Kees Cook <keescook@chromium.org>
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Sam Ravnborg <sam@ravnborg.org>,
        Ulf Magnusson <ulfalizer@gmail.com>,
        Nicholas Piggin <npiggin@gmail.com>,
        Emese Revfy <re.emese@gmail.com>, X86 ML <x86@kernel.org>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>
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Hi Kees,


2018-04-13 14:06 GMT+09:00 Masahiro Yamada <yamada.masahiro@socionext.com>:
> Since commit d677a4d60193 ("Makefile: support flag
> -fsanitizer-coverage=trace-cmp"), you miss to build the SANCOV
> plugin under some circumstances.
>
>   CONFIG_KCOV=y
>   CONFIG_KCOV_ENABLE_COMPARISONS=y
>   Your compiler does not support -fsanitize-coverage=trace-pc
>   Your compiler does not support -fsanitize-coverage=trace-cmp
>
> Under this condition, $(CFLAGS_KCOV) is not empty but contains a
> space, so the following ifeq-conditional is false.
>
>     ifeq ($(CFLAGS_KCOV),)
>
> Then, scripts/Makefile.gcc-plugins misses to add sancov_plugin.so to
> gcc-plugin-y while the SANCOV plugin is necessary as an alternative
> means.
>
> Fixes: d677a4d60193 ("Makefile: support flag -fsanitizer-coverage=trace-cmp")
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> ---


I am planning to queue this up to the fixes branch
since this is a bug fix.

Do you have any comment on this?


> Changes in v3:
>   - newly added
>
> Changes in v2: None
>
>  scripts/Makefile.gcc-plugins | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
> index b2a95af..7f5c862 100644
> --- a/scripts/Makefile.gcc-plugins
> +++ b/scripts/Makefile.gcc-plugins
> @@ -14,7 +14,7 @@ ifdef CONFIG_GCC_PLUGINS
>    endif
>
>    ifdef CONFIG_GCC_PLUGIN_SANCOV
> -    ifeq ($(CFLAGS_KCOV),)
> +    ifeq ($(strip $(CFLAGS_KCOV)),)
>        # It is needed because of the gcc-plugin.sh and gcc version checks.
>        gcc-plugin-$(CONFIG_GCC_PLUGIN_SANCOV)           += sancov_plugin.so
>
> --
> 2.7.4
>


-- 
Best Regards
Masahiro Yamada