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From:   Alexander Potapenko <glider@google.com>
Date:   Fri, 15 Jan 2021 15:11:40 +0100
Message-ID: <CAG_fn=VC=UPtVWfz81KeX+hEO1eC2PkZowWyFJbqz+jmiEeOQA@mail.gmail.com>
Subject: Re: [PATCH v3 08/15] kasan: add compiler barriers to KUNIT_EXPECT_KASAN_FAIL
To:     Andrey Konovalov <andreyknvl@google.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Marco Elver <elver@google.com>,
        Will Deacon <will.deacon@arm.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Peter Collingbourne <pcc@google.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Thu, Jan 14, 2021 at 8:36 PM Andrey Konovalov <andreyknvl@google.com> wrote:
>
> It might not be obvious to the compiler that the expression must be
> executed between writing and reading to fail_data. In this case, the
> compiler might reorder or optimize away some of the accesses, and
> the tests will fail.
>
> Add compiler barriers around the expression in KUNIT_EXPECT_KASAN_FAIL
> and use READ/WRITE_ONCE() for accessing fail_data fields.
>
> Link: https://linux-review.googlesource.com/id/I046079f48641a1d36fe627fc8827a9249102fd50
> Reviewed-by: Marco Elver <elver@google.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>