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From:   Marco Elver <elver@google.com>
Date:   Mon, 24 Aug 2020 13:49:14 +0200
Message-ID: <CANpmjNNf5pr=0hKVo92M9fEnCy7sYbv==6Bv_sVSmn=rZi7JEA@mail.gmail.com>
Subject: Re: [PATCH v2 5/6] kasan: add tests for workqueue stack recording
To:     Walter Wu <walter-zh.wu@mediatek.com>
Cc:     Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        wsd_upstream <wsd_upstream@mediatek.com>,
        linux-mediatek@lists.infradead.org,
        Andrey Konovalov <andreyknvl@google.com>
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On Mon, 24 Aug 2020 at 10:14, Walter Wu <walter-zh.wu@mediatek.com> wrote:
>
> Adds a test to verify workqueue stack recording and print it in
> KASAN report.
>
> The KASAN report was as follows(cleaned up slightly):
>
>  BUG: KASAN: use-after-free in kasan_workqueue_uaf
>
>  Freed by task 54:
>   kasan_save_stack+0x24/0x50
>   kasan_set_track+0x24/0x38
>   kasan_set_free_info+0x20/0x40
>   __kasan_slab_free+0x10c/0x170
>   kasan_slab_free+0x10/0x18
>   kfree+0x98/0x270
>   kasan_workqueue_work+0xc/0x18
>
>  Last potentially related work creation:
>   kasan_save_stack+0x24/0x50
>   kasan_record_wq_stack+0xa8/0xb8
>   insert_work+0x48/0x288
>   __queue_work+0x3e8/0xc40
>   queue_work_on+0xf4/0x118
>   kasan_workqueue_uaf+0xfc/0x190
>
> Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com>
> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Cc: Alexander Potapenko <glider@google.com>
> Cc: Matthias Brugger <matthias.bgg@gmail.com>
> Cc: Andrey Konovalov <andreyknvl@google.com>
> ---
>  lib/test_kasan.c | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)

These will majorly conflict with the KASAN-test KUnit rework, which I
don't know what the status is. AFAIK, these are not yet in -mm tree.

I think the KASAN-test KUnit rework has priority, as rebasing that
work on top of this patch is going to be difficult. So maybe these
test additions can be declared optional if there are conflicts coming,
and if that'll be the case you'll have to rebase and resend the test.

Thanks,
-- Marco