From 51337a9a3a404fde0f5337662ffc7699793dfeb5 Mon Sep 17 00:00:00 2001 From: Ada Couprie Diaz Date: Thu, 21 Aug 2025 13:07:35 +0100 Subject: [PATCH] kasan: fix GCC mem-intrinsic prefix with sw tags GCC doesn't support "hwasan-kernel-mem-intrinsic-prefix", only "asan-kernel-mem-intrinsic-prefix"[0], while LLVM supports both. This is already taken into account when checking "CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX", but not in the KASAN Makefile adding those parameters when "CONFIG_KASAN_SW_TAGS" is enabled. Replace the version check with "CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX", which already validates that mem-intrinsic prefix parameter can be used, and choose the correct name depending on compiler. GCC 13 and above trigger "CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX" which prevents `mem{cpy,move,set}()` being redefined in "mm/kasan/shadow.c" since commit 36be5cba99f6 ("kasan: treat meminstrinsic as builtins in uninstrumented files"), as we expect the compiler to prefix those calls with `__(hw)asan_` instead. But as the option passed to GCC has been incorrect, the compiler has not been emitting those prefixes, effectively never calling the instrumented versions of `mem{cpy,move,set}()` with "CONFIG_KASAN_SW_TAGS" enabled. If "CONFIG_FORTIFY_SOURCES" is enabled, this issue would be mitigated as it redefines `mem{cpy,move,set}()` and properly aliases the `__underlying_mem*()` that will be called to the instrumented versions. Link: https://lkml.kernel.org/r/20250821120735.156244-1-ada.coupriediaz@arm.com Link: https://gcc.gnu.org/onlinedocs/gcc-13.4.0/gcc/Optimize-Options.html [0] Signed-off-by: Ada Couprie Diaz Fixes: 36be5cba99f6 ("kasan: treat meminstrinsic as builtins in uninstrumented files") Reviewed-by: Yeoreum Yun Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Dmitriy Vyukov Cc: Marco Elver Cc: Marc Rutland Cc: Michael Ellerman Cc: Nathan Chancellor Cc: Vincenzo Frascino Cc: Signed-off-by: Andrew Morton --- scripts/Makefile.kasan | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan index 693dbbebebba..0ba2aac3b8dc 100644 --- a/scripts/Makefile.kasan +++ b/scripts/Makefile.kasan @@ -86,10 +86,14 @@ kasan_params += hwasan-instrument-stack=$(stack_enable) \ hwasan-use-short-granules=0 \ hwasan-inline-all-checks=0 -# Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*(). -ifeq ($(call clang-min-version, 150000)$(call gcc-min-version, 130000),y) - kasan_params += hwasan-kernel-mem-intrinsic-prefix=1 -endif +# Instrument memcpy/memset/memmove calls by using instrumented __(hw)asan_mem*(). +ifdef CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX + ifdef CONFIG_CC_IS_GCC + kasan_params += asan-kernel-mem-intrinsic-prefix=1 + else + kasan_params += hwasan-kernel-mem-intrinsic-prefix=1 + endif +endif # CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX endif # CONFIG_KASAN_SW_TAGS -- 2.25.1