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From:   Andrey Konovalov <andreyknvl@google.com>
Date:   Tue, 9 Feb 2021 16:02:25 +0100
Message-ID: <CAAeHK+yj9PR2Tw_xrpKKh=8GyNwgOaEu1pK8L6XL4zz0NtVs3A@mail.gmail.com>
Subject: Re: [PATCH v12 7/7] kasan: don't run tests in async mode
To:     Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        LKML <linux-kernel@vger.kernel.org>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        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>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
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On Tue, Feb 9, 2021 at 1:16 PM Vincenzo Frascino
<vincenzo.frascino@arm.com> wrote:
>
>
>
> On 2/9/21 12:02 PM, Catalin Marinas wrote:
> > On Mon, Feb 08, 2021 at 04:56:17PM +0000, Vincenzo Frascino wrote:
> >> From: Andrey Konovalov <andreyknvl@google.com>
> >>
> >> Asynchronous KASAN mode doesn't guarantee that a tag fault will be
> >> detected immediately and causes tests to fail. Forbid running them
> >> in asynchronous mode.
> >>
> >> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> >
> > That's missing your SoB.
> >
>
> Yes, I will add it in the next iteration.
>
> >> diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> >> index 7285dcf9fcc1..f82d9630cae1 100644
> >> --- a/lib/test_kasan.c
> >> +++ b/lib/test_kasan.c
> >> @@ -51,6 +51,10 @@ static int kasan_test_init(struct kunit *test)
> >>              kunit_err(test, "can't run KASAN tests with KASAN disabled");
> >>              return -1;
> >>      }
> >> +    if (kasan_flag_async) {
> >> +            kunit_err(test, "can't run KASAN tests in async mode");
> >> +            return -1;
> >> +    }
> >>
> >>      multishot = kasan_save_enable_multi_shot();
> >>      hw_set_tagging_report_once(false);
> >
> > I think we can still run the kasan tests in async mode if we check the
> > TFSR_EL1 at the end of each test by calling mte_check_tfsr_exit().
> >
>
> IIUC this was the plan for the future. But I let Andrey comment for more details.

If it's possible to implement, then it would be good to have. Doesn't
have to be a part of this series though.