On Fri, May 31, 2024 at 07:16:30PM +0900, Masahiro Yamada wrote: > On Fri, May 31, 2024 at 6:06 PM Arnd Bergmann <arnd@xxxxxxxx> wrote: > > > > On Fri, May 31, 2024, at 10:52, Masahiro Yamada wrote: > > > On Tue, May 28, 2024 at 8:36 PM Arnd Bergmann <arnd@xxxxxxxx> wrote: > > > > >> 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. > > > > > > > > > In my understanding, fortify-string is independent of KASAN. > > > > > > I do not understand why -fsanitize=kernel-address matters. > > > > Right, this is something I've failed to understand as well > > so far. > > > > >> 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? > > > > > > I set CONFIG_FORTIFY_SOURCE=y and CONFIG_KASAN=y, > > > but I did not observe such warnings. > > > Is this arch or compiler-specific? > > > > > > > > > Could you provide me with the steps to reproduce it? > > > > This is a randconfig .config file that shows it, but > > I've seen it in a lot of others: > > https://pastebin.com/raw/ESVzUeth > > > > If this doesn't reproduce it for you, I can try to narrow > > it down further. > > > > Arnd > > > Thanks, I was able to reproduce it. > > The issue happens with CONFIG_KASAN_SW_TAGS. > > I do not see the issue with CONFIG_KASAN_GENERIC. I'll try to figure this out. I suspect some kind of symbol name changes are happening? The fortify tests expect to find specifically-named symbols, so perhaps something is disrupting that? -- Kees Cook
