From: Arnd Bergmann <arnd@xxxxxxxx> Subject: kasan: fix kasan_check_read/write definitions Building little-endian allmodconfig kernels on arm64 started failing with the generated atomic.h implementation, since we now try to call kasan helpers from the EFI stub: aarch64-linux-gnu-ld: drivers/firmware/efi/libstub/arm-stub.stub.o: in function `atomic_set': include/generated/atomic-instrumented.h:44: undefined reference to `__efistub_kasan_check_write' I suspect that we get similar problems in other files that explicitly disable KASAN for some reason but call atomic_t based helper functions. We can fix this by checking the predefined __SANITIZE_ADDRESS__ macro that the compiler sets instead of checking CONFIG_KASAN, but this in turn requires a small hack in mm/kasan/common.c so we do see the extern declaration there instead of the inline function. Link: http://lkml.kernel.org/r/20181211133453.2835077-1-arnd@xxxxxxxx Fixes: b1864b828644 ("locking/atomics: build atomic headers as required") Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Reported-by: Anders Roxell <anders.roxell@xxxxxxxxxx> Acked-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> Cc: Will Deacon <will.deacon@xxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>, Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/kasan-checks.h | 2 +- mm/kasan/common.c | 2 ++ 2 files changed, 3 insertions(+), 1 deletion(-) --- a/include/linux/kasan-checks.h~kasan-fix-kasan_check_read-write-definitions +++ a/include/linux/kasan-checks.h @@ -2,7 +2,7 @@ #ifndef _LINUX_KASAN_CHECKS_H #define _LINUX_KASAN_CHECKS_H -#ifdef CONFIG_KASAN +#if defined(__SANITIZE_ADDRESS__) || defined(__KASAN_INTERNAL) void kasan_check_read(const volatile void *p, unsigned int size); void kasan_check_write(const volatile void *p, unsigned int size); #else --- a/mm/kasan/common.c~kasan-fix-kasan_check_read-write-definitions +++ a/mm/kasan/common.c @@ -14,6 +14,8 @@ * */ +#define __KASAN_INTERNAL + #include <linux/export.h> #include <linux/interrupt.h> #include <linux/init.h> _
