From: Masahiro Yamada <masahiroy@kernel.org>
To: Arnd Bergmann <arnd@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
Michal Marek <michal.lkml@markovi.net>,
Arnd Bergmann <arnd@arndb.de>, stable <stable@vger.kernel.org>,
Ard Biesheuvel <ardb@kernel.org>,
Kees Cook <keescook@chromium.org>,
Rikard Falkeborn <rikard.falkeborn@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] kbuild: avoid static_assert for genksyms
Date: Sun, 6 Dec 2020 11:48:21 +0900 [thread overview]
Message-ID: <CAK7LNAR50sq8O-5yg1O7760JAd3-GPHSLGGG=7kPtm9dbDDqwg@mail.gmail.com> (raw)
In-Reply-To: <20201203230955.1482058-1-arnd@kernel.org>
On Fri, Dec 4, 2020 at 8:10 AM Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> genksyms does not know or care about the _Static_assert() built-in,
> and sometimes falls back to ignoring the later symbols, which causes
> undefined behavior such as
>
> WARNING: modpost: EXPORT symbol "ethtool_set_ethtool_phy_ops" [vmlinux] version generation failed, symbol will not be versioned.
> ld: net/ethtool/common.o: relocation R_AARCH64_ABS32 against `__crc_ethtool_set_ethtool_phy_ops' can not be used when making a shared object
> net/ethtool/common.o:(_ftrace_annotated_branch+0x0): dangerous relocation: unsupported relocation
>
> Redefine static_assert for genksyms to avoid that.
Please tell the CONFIG options needed to reproduce this.
I do not see it.
>
> Cc: stable@vger.kernel.org
> Suggested-by: Ard Biesheuvel <ardb@kernel.org>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> include/linux/build_bug.h | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/include/linux/build_bug.h b/include/linux/build_bug.h
> index e3a0be2c90ad..7bb66e15b481 100644
> --- a/include/linux/build_bug.h
> +++ b/include/linux/build_bug.h
> @@ -77,4 +77,9 @@
> #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
> #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
>
> +#ifdef __GENKSYMS__
> +/* genksyms gets confused by _Static_assert */
> +#define _Static_assert(expr, ...)
> +#endif
> +
> #endif /* _LINUX_BUILD_BUG_H */
> --
> 2.27.0
>
--
Best Regards
Masahiro Yamada
next prev parent reply other threads:[~2020-12-06 4:08 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-03 23:09 [PATCH] kbuild: avoid static_assert for genksyms Arnd Bergmann
2020-12-06 2:48 ` Masahiro Yamada [this message]
2020-12-07 8:53 ` Ard Biesheuvel
2020-12-10 16:12 ` Marco Elver
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