kasan: disable the built-in 'memset' function

In function kasan_set_poison:
{
  ...

  while (size--)
    {
      p[size] = value;
    }
}
This will optimize to 'memset' function when compile option > O2.

But the memset must be instrument by kasan, so there is recursive

Signed-off-by: ligd <liguiding1@xiaomi.com>

mm/kasan/CMakeLists.txt

@@ -25,6 +25,7 @@ if(CONFIG_MM_KASAN)
   list(APPEND SRCS generic.c)
   set_source_files_properties(generic.c PROPERTIES COMPILE_FLAGS
                                                    -fno-sanitize=kernel-address)
+  set_source_files_properties(generic.c PROPERTIES COMPILE_FLAGS -fno-builtin)
   set_source_files_properties(generic.c PROPERTIES COMPILE_FLAGS -fno-lto)
 endif()
 

mm/kasan/Make.defs

@@ -43,6 +43,8 @@ ifeq ($(CONFIG_MM_KASAN),y)
   endif
 endif
 
+CFLAGS += -fno-builtin
+
 # Add the core heap directory to the build
 
 DEPPATH += --dep-path kasan