6.6-stable review patch. If anyone has any objections, please let me know.
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From: Ada Couprie Diaz ada.coupriediaz@arm.com
[ Upstream commit 51337a9a3a404fde0f5337662ffc7699793dfeb5 ]
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 ada.coupriediaz@arm.com Fixes: 36be5cba99f6 ("kasan: treat meminstrinsic as builtins in uninstrumented files") Reviewed-by: Yeoreum Yun yeoreum.yun@arm.com Cc: Alexander Potapenko glider@google.com Cc: Andrey Konovalov andreyknvl@gmail.com Cc: Andrey Ryabinin ryabinin.a.a@gmail.com Cc: Dmitriy Vyukov dvyukov@google.com Cc: Marco Elver elver@google.com Cc: Marc Rutland mark.rutland@arm.com Cc: Michael Ellerman mpe@ellerman.id.au Cc: Nathan Chancellor nathan@kernel.org Cc: Vincenzo Frascino vincenzo.frascino@arm.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org [ kasan_params => CFLAGS_KASAN ] Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- scripts/Makefile.kasan | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
--- a/scripts/Makefile.kasan +++ b/scripts/Makefile.kasan @@ -68,10 +68,14 @@ CFLAGS_KASAN := -fsanitize=kernel-hwaddr $(call cc-param,hwasan-inline-all-checks=0) \ $(instrumentation_flags)
-# Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*(). -ifeq ($(call clang-min-version, 150000)$(call gcc-min-version, 130000),y) -CFLAGS_KASAN += $(call cc-param,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 + CFLAGS_KASAN += $(call cc-param,asan-kernel-mem-intrinsic-prefix=1) + else + CFLAGS_KASAN += $(call cc-param,hwasan-kernel-mem-intrinsic-prefix=1) + endif +endif # CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX
endif # CONFIG_KASAN_SW_TAGS