[PATCH] ARM: disable KASAN in call stack capturing routines

[Ard Biesheuvel]

KASAN uses the routines in stacktrace.c to capture the call stack each
time memory gets allocated or freed. Some of these routines are also
used to log CPU and memory context when exceptions are taken, and so
in some cases, memory accesses may be made that are not strictly in
line with the KASAN constraints, and may therefore trigger false KASAN
positives.

So follow the example set by other architectures, and simply disable
KASAN instrumentation for these routines.

Reviewed-by: Linus Walleij <linus.walleij at linaro.org>
Signed-off-by: Ard Biesheuvel <ardb at kernel.org>
---
 arch/arm/kernel/Makefile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 9e465efcc8b6..c38c8b019d24 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -21,6 +21,9 @@ obj-y		:= elf.o entry-common.o irq.o opcodes.o \
 		   setup.o signal.o sigreturn_codes.o \
 		   stacktrace.o sys_arm.o time.o traps.o
 
+KASAN_SANITIZE_stacktrace.o := n
+KASAN_SANITIZE_traps.o := n
+
 ifneq ($(CONFIG_ARM_UNWIND),y)
 obj-$(CONFIG_FRAME_POINTER)	+= return_address.o
 endif
-- 
2.17.1