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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
        Ard Biesheuvel <ardb@kernel.org>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Michal Marek <michal.lkml@markovi.net>,
        Kees Cook <keescook@chromium.org>,
        Rikard Falkeborn <rikard.falkeborn@gmail.com>,
        Marco Elver <elver@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 4.14 013/242] kbuild: avoid static_assert for genksyms
Date:   Mon, 28 Dec 2020 13:46:58 +0100
Message-Id: <20201228124905.315839390@linuxfoundation.org>
In-Reply-To: <20201228124904.654293249@linuxfoundation.org>
References: <20201228124904.654293249@linuxfoundation.org>
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From: Arnd Bergmann <arnd@arndb.de>

commit 14dc3983b5dff513a90bd5a8cc90acaf7867c3d0 upstream.

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.

Link: https://lkml.kernel.org/r/20201203230955.1482058-1-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Cc: Marco Elver <elver@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 include/linux/build_bug.h |    5 +++++
 1 file changed, 5 insertions(+)

--- a/include/linux/build_bug.h
+++ b/include/linux/build_bug.h
@@ -82,4 +82,9 @@
 
 #endif	/* __CHECKER__ */
 
+#ifdef __GENKSYMS__
+/* genksyms gets confused by _Static_assert */
+#define _Static_assert(expr, ...)
+#endif
+
 #endif	/* _LINUX_BUILD_BUG_H */