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From: Nick Desaulniers <ndesaulniers@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
	kbuild test robot <lkp@intel.com>,
	Kees Cook <keescook@chromium.org>,
	Nathan Chancellor <natechancellor@gmail.com>,
	Masahiro Yamada <yamada.masahiro@socionext.com>,
	Matthias Maennich <maennich@google.com>,
	Jessica Yu <jeyu@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Will Deacon <will@kernel.org>,
	linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com
Subject: [PATCH] export.h: fix section name for CONFIG_TRIM_UNUSED_KSYMS for Clang
Date: Tue, 29 Sep 2020 12:07:00 -0700	[thread overview]
Message-ID: <20200929190701.398762-1-ndesaulniers@google.com> (raw)

When enabling CONFIG_TRIM_UNUSED_KSYMS, the linker will warn about the
orphan sections:
(".discard.ksym") is being placed in '".discard.ksym"'
repeatedly when linking vmlinux. This is because the stringification
operator, `#`, in the preprocessor escapes strings.  GCC and Clang
differ in how they treat section names that contain \".

The portable solution is to not use a string literal with the
preprocessor stringification operator.

Link: https://bugs.llvm.org/show_bug.cgi?id=42950
Link: https://github.com/ClangBuiltLinux/linux/issues/1166
Fixes: commit bbda5ec671d3 ("kbuild: simplify dependency generation for CONFIG_TRIM_UNUSED_KSYMS")
Reported-by: kbuild test robot <lkp@intel.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
 include/linux/export.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/export.h b/include/linux/export.h
index fceb5e855717..8933ff6ad23a 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -130,7 +130,7 @@ struct kernel_symbol {
  * discarded in the final link stage.
  */
 #define __ksym_marker(sym)	\
-	static int __ksym_marker_##sym[0] __section(".discard.ksym") __used
+	static int __ksym_marker_##sym[0] __section(.discard.ksym) __used
 
 #define __EXPORT_SYMBOL(sym, sec, ns)					\
 	__ksym_marker(sym);						\
-- 
2.28.0.709.gb0816b6eb0-goog


             reply	other threads:[~2020-09-29 19:07 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-29 19:07 Nick Desaulniers [this message]
2020-09-29 23:44 ` [PATCH] export.h: fix section name for CONFIG_TRIM_UNUSED_KSYMS for Clang Kees Cook
2020-09-30 16:26 ` Nathan Chancellor
2020-09-30 16:43 ` Sedat Dilek

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