From 6ba912f1c081448cf3d1fa9ada9115aae4594ac4 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann 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 See-also: 3e6631485fae ("vmlinux.lds.h: Keep .ctors.* with .ctors") Signed-off-by: Arnd Bergmann Reviewed-by: Marco Elver Signed-off-by: Paul E. McKenney --- lib/Kconfig.kcsan | 1 + 1 file changed, 1 insertion(+) diff --git a/lib/Kconfig.kcsan b/lib/Kconfig.kcsan index 375575a5a0e3..cb926b393556 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