From: Alexander Potapenko <glider@google.com>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Dmitry Vyukov <dvyukov@google.com>,
Marco Elver <elver@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Will Deacon <will.deacon@arm.com>,
Andrey Ryabinin <aryabinin@virtuozzo.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>
Subject: Re: [PATCH 07/11] kasan: add compiler barriers to KUNIT_EXPECT_KASAN_FAIL
Date: Tue, 12 Jan 2021 09:18:24 +0100 [thread overview]
Message-ID: <CAG_fn=Uqp6dt5VGF8Dt6FeQzDgcEbVY8fs+5+wyMp2d1Z98sEw@mail.gmail.com> (raw)
In-Reply-To: <a37dab02f89ad93cc986a87866da74fb8be1850d.1609871239.git.andreyknvl@google.com>
On Tue, Jan 5, 2021 at 7:28 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.
Have you seen this happen in practice?
Are these accesses to fail_data that are optimized (in which case we
could make it volatile), or some part of the expression?
Note that compiler barriers won't probably help against removing
memory accesses, they only prevent reordering.
> + barrier(); \
> expression; \
> + barrier(); \
The need for barriers is not obvious to the reader, so a comment in
the code clarifying that would be nice.
next prev parent reply other threads:[~2021-01-12 8:18 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-05 18:27 [PATCH 00/11] kasan: HW_TAGS tests support and fixes Andrey Konovalov
2021-01-05 18:27 ` [PATCH 01/11] kasan: prefix exported functions with kasan_ Andrey Konovalov
2021-01-12 7:38 ` Alexander Potapenko
2021-01-12 11:19 ` Marco Elver
2021-01-05 18:27 ` [PATCH 02/11] kasan: clarify HW_TAGS impact on TBI Andrey Konovalov
2021-01-12 7:40 ` Alexander Potapenko
2021-01-12 11:38 ` Marco Elver
2021-01-05 18:27 ` [PATCH 03/11] kasan: clean up comments in tests Andrey Konovalov
2021-01-12 7:53 ` Alexander Potapenko
2021-01-12 17:55 ` Andrey Konovalov
2021-01-12 13:07 ` Marco Elver
2021-01-05 18:27 ` [PATCH 04/11] kasan: add match-all tag tests Andrey Konovalov
2021-01-12 8:04 ` Alexander Potapenko
2021-01-12 18:10 ` Andrey Konovalov
2021-01-12 13:17 ` Marco Elver
2021-01-12 18:11 ` Andrey Konovalov
2021-01-05 18:27 ` [PATCH 05/11] kasan, arm64: allow using KUnit tests with HW_TAGS mode Andrey Konovalov
2021-01-12 19:01 ` Catalin Marinas
2021-01-15 13:11 ` Andrey Konovalov
2021-01-15 15:04 ` Vincenzo Frascino
2021-01-05 18:27 ` [PATCH 06/11] kasan: rename CONFIG_TEST_KASAN_MODULE Andrey Konovalov
2021-01-12 8:09 ` Alexander Potapenko
2021-01-12 18:26 ` Andrey Konovalov
2021-01-12 13:33 ` Marco Elver
2021-01-12 18:28 ` Andrey Konovalov
2021-01-05 18:27 ` [PATCH 07/11] kasan: add compiler barriers to KUNIT_EXPECT_KASAN_FAIL Andrey Konovalov
2021-01-12 8:18 ` Alexander Potapenko [this message]
2021-01-12 19:50 ` Andrey Konovalov
2021-01-12 19:57 ` Andrey Konovalov
2021-01-12 13:34 ` Marco Elver
2021-01-05 18:27 ` [PATCH 08/11] kasan: adopt kmalloc_uaf2 test to HW_TAGS mode Andrey Konovalov
2021-01-12 8:25 ` Alexander Potapenko
2021-01-12 20:04 ` Andrey Konovalov
2021-01-12 13:39 ` Marco Elver
2021-01-12 20:05 ` Andrey Konovalov
2021-01-05 18:27 ` [PATCH 09/11] kasan: fix memory corruption in kasan_bitops_tags test Andrey Konovalov
2021-01-12 8:30 ` Alexander Potapenko
2021-01-12 20:06 ` Andrey Konovalov
2021-01-13 12:30 ` Alexander Potapenko
2021-01-12 13:55 ` Marco Elver
2021-01-05 18:27 ` [PATCH 10/11] kasan: fix bug detection via ksize for HW_TAGS mode Andrey Konovalov
2021-01-05 21:04 ` kernel test robot
2021-01-06 0:09 ` kernel test robot
2021-01-07 0:02 ` Andrew Morton
2021-01-07 1:59 ` Andrey Konovalov
2021-01-12 14:32 ` Marco Elver
2021-01-12 21:16 ` Andrey Konovalov
2021-01-12 22:54 ` Marco Elver
2021-01-05 18:27 ` [PATCH 11/11] kasan: add proper page allocator tests Andrey Konovalov
2021-01-12 8:57 ` Alexander Potapenko
2021-01-12 14:34 ` Marco Elver
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