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From: Andrey Konovalov <andreyknvl@gmail.com>
Date: Wed, 10 Apr 2024 13:11:32 +0200
Message-ID: <CA+fCnZen+5XC4LFYuzhdAjSjY_Jh0Yk=KYXxcYxkMDNj3kY9kA@mail.gmail.com>
Subject: Re: [PATCH 4/4] x86/percpu: Use C for percpu read/write accessors
To: Uros Bizjak <ubizjak@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>, Linus Torvalds <torvalds@linux-foundation.org>, x86@kernel.org, 
	linux-kernel@vger.kernel.org, Andy Lutomirski <luto@kernel.org>, 
	Nadav Amit <namit@vmware.com>, Brian Gerst <brgerst@gmail.com>, 
	Denys Vlasenko <dvlasenk@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>, 
	Peter Zijlstra <peterz@infradead.org>, Thomas Gleixner <tglx@linutronix.de>, 
	Borislav Petkov <bp@alien8.de>, Josh Poimboeuf <jpoimboe@redhat.com>, 
	Andrey Ryabinin <ryabinin.a.a@gmail.com>, Alexander Potapenko <glider@google.com>, 
	Dmitry Vyukov <dvyukov@google.com>, kasan-dev@googlegroups.com
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On Mon, Oct 9, 2023 at 4:35=E2=80=AFPM Uros Bizjak <ubizjak@gmail.com> wrot=
e:
>
> On Mon, Oct 9, 2023 at 1:41=E2=80=AFPM Ingo Molnar <mingo@kernel.org> wro=
te:
> >
> >
> > * Uros Bizjak <ubizjak@gmail.com> 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 qu=
irk.
> >
> > Something like:
> >
> >         depends on CC_HAS_NAMED_AS
> >         depends on SMP
> >         #
> >         # -fsanitize=3Dkernel-address (KASAN) is at the moment incompat=
ible
> >         # 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=3D111736

Filed a KASAN bug to track this:
https://bugzilla.kernel.org/show_bug.cgi?id=3D218703

Thanks!