Re: [PATCH v5 6/6] kasan: Forbid kunit tests when async mode is enabled

From: Catalin Marinas <catalin.marinas@arm.com>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	kasan-dev <kasan-dev@googlegroups.com>,
	Will Deacon <will@kernel.org>, Dmitry Vyukov <dvyukov@google.com>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Alexander Potapenko <glider@google.com>,
	Marco Elver <elver@google.com>,
	Evgenii Stepanov <eugenis@google.com>,
	Branislav Rankov <Branislav.Rankov@arm.com>
Subject: Re: [PATCH v5 6/6] kasan: Forbid kunit tests when async mode is enabled
Date: Fri, 22 Jan 2021 12:00:08 +0000	[thread overview]
Message-ID: <20210122120007.GB8567@gaia> (raw)
In-Reply-To: <CAAeHK+yaFtXUDVExoyqkYysOPdxLVhfY53nb-msFYEJLZx6k8Q@mail.gmail.com>

On Thu, Jan 21, 2021 at 06:40:35PM +0100, Andrey Konovalov wrote:
> On Thu, Jan 21, 2021 at 5:40 PM Vincenzo Frascino
> <vincenzo.frascino@arm.com> wrote:
> >
> > Architectures supported by KASAN_HW_TAGS can provide a sync or async
> > mode of execution. KASAN KUNIT tests can be executed only when sync
> > mode is enabled.
> >
> > Forbid the execution of the KASAN KUNIT tests when async mode is
> > enabled.
> >
> > Cc: Dmitry Vyukov <dvyukov@google.com>
> > Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
> > Cc: Alexander Potapenko <glider@google.com>
> > Cc: Andrey Konovalov <andreyknvl@google.com>
> > Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
> > ---
> >  lib/test_kasan.c | 5 +++++
> >  mm/kasan/kasan.h | 2 ++
> >  2 files changed, 7 insertions(+)
> >
> > diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> > index 7285dcf9fcc1..1306f707b4fe 100644
> > --- a/lib/test_kasan.c
> > +++ b/lib/test_kasan.c
> > @@ -52,6 +52,11 @@ static int kasan_test_init(struct kunit *test)
> >                 return -1;
> >         }
> >
> > +       if (!hw_is_mode_sync()) {
> > +               kunit_err(test, "can't run KASAN tests in async mode");
> > +               return -1;
> > +       }
> 
> I'd rather implement this check at the KASAN level, than in arm64
> code. Just the way kasan_stack_collection_enabled() is implemented.
> 
> Feel free to drop this change and the previous patch, I'll implement
> this myself later.

I agree, it makes sense.

-- 
Catalin