Clang 15 will provide an option to prefix calls to memcpy/memset/memmove with __asan_ in instrumented functions: https://reviews.llvm.org/D122724 GCC will add support in future: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108777 Use it to regain KASAN instrumentation of memcpy/memset/memmove on architectures that require noinstr to be really free from instrumented mem*() functions (all GENERIC_ENTRY architectures). Fixes: 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions") Signed-off-by: Marco Elver <elver@xxxxxxxxxx> --- v3: * Resend with actual fix. v2: * Use asan-kernel-mem-intrinsic-prefix=1, so that once GCC supports the param, it also works there (it needs the =1). The Fixes tag is just there to show the dependency, and that people shouldn't apply this patch without 69d4c0d32186. --- scripts/Makefile.kasan | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan index b9e94c5e7097..3b35a88af60d 100644 --- a/scripts/Makefile.kasan +++ b/scripts/Makefile.kasan @@ -38,6 +38,13 @@ endif CFLAGS_KASAN += $(call cc-param,asan-stack=$(stack_enable)) +ifdef CONFIG_GENERIC_ENTRY +# Instrument memcpy/memset/memmove calls by using instrumented __asan_mem*() +# instead. With compilers that don't support this option, compiler-inserted +# memintrinsics won't be checked by KASAN. +CFLAGS_KASAN += $(call cc-param,asan-kernel-mem-intrinsic-prefix=1) +endif + endif # CONFIG_KASAN_GENERIC ifdef CONFIG_KASAN_SW_TAGS -- 2.39.1.581.gbfd45094c4-goog
