From 6ba912f1c081448cf3d1fa9ada9115aae4594ac4 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Wed, 15 Feb 2023 10:14:48 +0100
Subject: [PATCH] kcsan: select CONFIG_CONSTRUCTORS
Building a kcsan enabled kernel for x86_64 with gcc-11 results in a lot
of build warnings or errors without CONFIG_CONSTRUCTORS:
x86_64-linux-ld: error: unplaced orphan section `.ctors.65436' from `arch/x86/lib/copy_mc.o'
x86_64-linux-ld: error: unplaced orphan section `.ctors.65436' from `arch/x86/lib/cpu.o'
x86_64-linux-ld: error: unplaced orphan section `.ctors.65436' from `arch/x86/lib/csum-partial_64.o'
x86_64-linux-ld: error: unplaced orphan section `.ctors.65436' from `arch/x86/lib/csum-wrappers_64.o'
x86_64-linux-ld: error: unplaced orphan section `.ctors.65436' from `arch/x86/lib/insn-eval.o'
x86_64-linux-ld: error: unplaced orphan section `.ctors.65436' from `arch/x86/lib/insn.o'
x86_64-linux-ld: error: unplaced orphan section `.ctors.65436' from `arch/x86/lib/misc.o'
The same thing has been reported for mips64. I can't reproduce it for
any other compiler version, so I don't know if constructors are always
required here or if this is a gcc-11 specific implementation detail.
I see no harm in always enabling constructors here, and this reliably
fixes the build warnings for me.
Link: https://lore.kernel.org/lkml/202204181801.r3MMkwJv-lkp@intel.com/T/
Cc: Kees Cook <keescook@chromium.org>
See-also: 3e6631485fae ("vmlinux.lds.h: Keep .ctors.* with .ctors")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
lib/Kconfig.kcsan | 1 +
1 file changed, 1 insertion(+)
diff --git a/lib/Kconfig.kcsan b/lib/Kconfig.kcsan
index 375575a5a0e3c..cb926b3935567 100644
--- a/lib/Kconfig.kcsan
+++ b/lib/Kconfig.kcsan
@@ -14,6 +14,7 @@ menuconfig KCSAN
bool "KCSAN: dynamic data race detector"
depends on HAVE_ARCH_KCSAN && HAVE_KCSAN_COMPILER
depends on DEBUG_KERNEL && !KASAN
+ select CONSTRUCTORS
select STACKTRACE
help
The Kernel Concurrency Sanitizer (KCSAN) is a dynamic
--
GitLab