Re: [tip: x86/bugs] x86/retpoline: Ensure default return thunk isn't used at runtime

[Nick Desaulniers]

+ Marco, Dmitry

On Mon, Oct 16, 2023 at 10:28 PM Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:
>
> On Tue, Oct 17, 2023 at 04:31:09AM +0000, Kaplan, David wrote:
> > Perhaps another option would be to not compile these two files with KCSAN, as they are already excluded from KASAN and GCOV it looks like.
>
> I think the latter would be the easy fix, does this make it go away?

Yeah, usually when I see the other sanitizers being disabled on a per
object basis, I think "where there's smoke, there's fire."

Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Reported-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Closes: https://lore.kernel.org/lkml/20231016214810.GA3942238@dev-arch.thelio-3990X/

>
> diff --git a/init/Makefile b/init/Makefile
> index ec557ada3c12..cbac576c57d6 100644
> --- a/init/Makefile
> +++ b/init/Makefile
> @@ -60,4 +60,5 @@ include/generated/utsversion.h: FORCE
>  $(obj)/version-timestamp.o: include/generated/utsversion.h
>  CFLAGS_version-timestamp.o := -include include/generated/utsversion.h
>  KASAN_SANITIZE_version-timestamp.o := n
> +KCSAN_SANITIZE_version-timestamp.o := n
>  GCOV_PROFILE_version-timestamp.o := n
> diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
> index 3cd6ca15f390..c9f3e03124d7 100644
> --- a/scripts/Makefile.vmlinux
> +++ b/scripts/Makefile.vmlinux
> @@ -19,6 +19,7 @@ quiet_cmd_cc_o_c = CC      $@
>
>  ifdef CONFIG_MODULES
>  KASAN_SANITIZE_.vmlinux.export.o := n
> +KCSAN_SANITIZE_.vmlinux.export.o := n
>  GCOV_PROFILE_.vmlinux.export.o := n
>  targets += .vmlinux.export.o
>  vmlinux: .vmlinux.export.o
>


-- 
Thanks,
~Nick Desaulniers