On Mon, May 6, 2024, at 15:35, Masahiro Yamada wrote: > The objtool, sanitizers (KASAN, UBSAN, etc.), and profilers (GCOV, etc.) > are intended for kernel space objects. To exclude objects from their > coverage, you need to set variables such as OBJECT_FILES_NON_STNDARD=y, > KASAN_SANITIZE=n, etc. > > For instance, the following are not kernel objects, and therefore should > opt out of coverage: > > - vDSO > - purgatory > - bootloader (arch/*/boot/) > > Kbuild can detect these cases without relying on such variables because > objects not directly linked to vmlinux or modules are considered > "non-standard objects". > > Detecting objects linked to vmlinux or modules is straightforward: > > - objects added to obj-y are linked to vmlinux > - objects added to lib-y are linked to vmlinux > - objects added to obj-m are linked to modules > I noticed new randconfig build warnings and bisected them down to this patch: warning: unsafe memchr_inv() usage lacked '__read_overflow' symbol in lib/test_fortify/read_overflow-memchr_inv.c warning: unsafe memchr() usage lacked '__read_overflow' warning in lib/test_fortify/read_overflow-memchr.c warning: unsafe memscan() usage lacked '__read_overflow' symbol in lib/test_fortify/read_overflow-memscan.c warning: unsafe memcmp() usage lacked '__read_overflow' warning in lib/test_fortify/read_overflow-memcmp.c warning: unsafe memcpy() usage lacked '__read_overflow2' symbol in lib/test_fortify/read_overflow2-memcpy.c warning: unsafe memcmp() usage lacked '__read_overflow2' warning in lib/test_fortify/read_overflow2-memcmp.c warning: unsafe memmove() usage lacked '__read_overflow2' symbol in lib/test_fortify/read_overflow2-memmove.c warning: unsafe memcpy() usage lacked '__read_overflow2_field' symbol in lib/test_fortify/read_overflow2_field-memcpy.c warning: unsafe memmove() usage lacked '__read_overflow2_field' symbol in lib/test_fortify/read_overflow2_field-memmove.c warning: unsafe memcpy() usage lacked '__write_overflow' symbol in lib/test_fortify/write_overflow-memcpy.c warning: unsafe memmove() usage lacked '__write_overflow' symbol in lib/test_fortify/write_overflow-memmove.c warning: unsafe memset() usage lacked '__write_overflow' symbol in lib/test_fortify/write_overflow-memset.c warning: unsafe strcpy() usage lacked '__write_overflow' symbol in lib/test_fortify/write_overflow-strcpy-lit.c warning: unsafe strcpy() usage lacked '__write_overflow' symbol in lib/test_fortify/write_overflow-strcpy.c warning: unsafe strncpy() usage lacked '__write_overflow' symbol in lib/test_fortify/write_overflow-strncpy-src.c warning: unsafe strncpy() usage lacked '__write_overflow' symbol in lib/test_fortify/write_overflow-strncpy.c warning: unsafe strscpy() usage lacked '__write_overflow' symbol in lib/test_fortify/write_overflow-strscpy.c warning: unsafe memcpy() usage lacked '__write_overflow_field' symbol in lib/test_fortify/write_overflow_field-memcpy.c warning: unsafe memmove() usage lacked '__write_overflow_field' symbol in lib/test_fortify/write_overflow_field-memmove.c warning: unsafe memset() usage lacked '__write_overflow_field' symbol in lib/test_fortify/write_overflow_field-memset.c I don't understand the nature of this warning, but I see that your patch ended up dropping -fsanitize=kernel-address from the compiler flags because the lib/test_fortify/*.c files don't match the $(is-kernel-object) rule. Adding back -fsanitize=kernel-address shuts up these warnings. I've applied a local workaround in my randconfig tree diff --git a/lib/Makefile b/lib/Makefile index ddcb76b294b5..d7b8fab64068 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -425,5 +425,7 @@ $(obj)/$(TEST_FORTIFY_LOG): $(addprefix $(obj)/, $(TEST_FORTIFY_LOGS)) FORCE # Fake dependency to trigger the fortify tests. ifeq ($(CONFIG_FORTIFY_SOURCE),y) +ifndef CONFIG_KASAN $(obj)/string.o: $(obj)/$(TEST_FORTIFY_LOG) +endif endif which I don't think we want upstream. Can you and Kees come up with a proper fix instead? Arnd