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From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, ardb@kernel.org, arnd@arndb.de,
	elver@google.com, keescook@chromium.org, linux-mm@kvack.org,
	masahiroy@kernel.org, michal.lkml@markovi.net,
	mm-commits@vger.kernel.org, rikard.falkeborn@gmail.com,
	stable@vger.kernel.org, torvalds@linux-foundation.org
Subject: [patch 4/8] kbuild: avoid static_assert for genksyms
Date: Fri, 11 Dec 2020 13:36:38 -0800	[thread overview]
Message-ID: <20201211213638.89W7IFB2b%akpm@linux-foundation.org> (raw)
In-Reply-To: <20201211133555.88407977f082963499ed343c@linux-foundation.org>

From: Arnd Bergmann <arnd@arndb.de>
Subject: kbuild: avoid static_assert for genksyms

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>
---

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

--- a/include/linux/build_bug.h~kbuild-avoid-static_assert-for-genksyms
+++ a/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 */
_

  parent reply	other threads:[~2020-12-11 22:37 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-11 21:35 incoming Andrew Morton
2020-12-11 21:36 ` [patch 1/8] revert "mm/filemap: add static for function __add_to_page_cache_locked" Andrew Morton
2020-12-11 21:36 ` [patch 2/8] proc: use untagged_addr() for pagemap_read addresses Andrew Morton
2020-12-11 21:36 ` [patch 3/8] selftest/fpu: avoid clang warning Andrew Morton
2020-12-11 21:36 ` Andrew Morton [this message]
2020-12-11 21:36 ` [patch 5/8] initramfs: fix clang build failure Andrew Morton
2020-12-11 21:36 ` [patch 6/8] elfcore: fix building with clang Andrew Morton
2020-12-11 21:36 ` [patch 7/8] kasan: fix object remaining in offline per-cpu quarantine Andrew Morton
2020-12-11 21:36 ` [patch 8/8] mm/hugetlb: clear compound_nr before freeing gigantic pages Andrew Morton

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