Re: [PATCH 4/4] x86/percpu: Use C for percpu read/write accessors

[Andrey Konovalov]

On Mon, Oct 9, 2023 at 4:35 PM Uros Bizjak <ubizjak@xxxxxxxxx> wrote:
>
> On Mon, Oct 9, 2023 at 1:41 PM Ingo Molnar <mingo@xxxxxxxxxx> wrote:
> >
> >
> > * Uros Bizjak <ubizjak@xxxxxxxxx> wrote:
> >
> > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> > > index ecb256954351..1edf4a5b93ca 100644
> > > --- a/arch/x86/Kconfig
> > > +++ b/arch/x86/Kconfig
> > > @@ -2393,7 +2393,7 @@ config CC_HAS_NAMED_AS
> > >
> > >  config USE_X86_SEG_SUPPORT
> > >       def_bool y
> > > -     depends on CC_HAS_NAMED_AS && SMP
> > > +     depends on CC_HAS_NAMED_AS && SMP && !KASAN
> > > +     depends on CC_HAS_NAMED_AS && SMP && !KASAN
> >
> > So I'd rather express this as a Kconfig quirk line, and explain each quirk.
> >
> > Something like:
> >
> >         depends on CC_HAS_NAMED_AS
> >         depends on SMP
> >         #
> >         # -fsanitize=kernel-address (KASAN) is at the moment incompatible
> >         # with named address spaces - see GCC bug #12345.
> >         #
> >         depends on !KASAN
>
> This is now PR sanitizer/111736 [1], but perhaps KASAN people [CC'd]
> also want to be notified about this problem.
>
> [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111736

Filed a KASAN bug to track this:
https://bugzilla.kernel.org/show_bug.cgi?id=218703

Thanks!