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From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Mon, 25 May 2020 11:56:42 +0200
Message-ID: <CACT4Y+axrVeCwdEg_yWH57jF7gcKT429J4wVwsNGPuARcPMiLg@mail.gmail.com>
Subject: Re: [PATCH v6 3/4] kasan: add tests for call_rcu stack recording
To:     Walter Wu <walter-zh.wu@mediatek.com>
Cc:     Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Linux-MM <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
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On Fri, May 22, 2020 at 4:02 AM Walter Wu <walter-zh.wu@mediatek.com> wrote:
>
> Test call_rcu() call stack recording and verify whether it correctly
> is printed in KASAN report.

Reviewed-and-tested-by: Dmitry Vyukov <dvyukov@google.com>

> 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>
> ---
>  lib/test_kasan.c | 30 ++++++++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
>
> diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> index e3087d90e00d..6e5fb05d42d8 100644
> --- a/lib/test_kasan.c
> +++ b/lib/test_kasan.c
> @@ -792,6 +792,35 @@ static noinline void __init vmalloc_oob(void)
>  static void __init vmalloc_oob(void) {}
>  #endif
>
> +static struct kasan_rcu_info {
> +       int i;
> +       struct rcu_head rcu;
> +} *global_ptr;
> +
> +static noinline void __init kasan_rcu_reclaim(struct rcu_head *rp)
> +{
> +       struct kasan_rcu_info *fp = container_of(rp,
> +                                               struct kasan_rcu_info, rcu);
> +
> +       kfree(fp);
> +       fp->i = 1;
> +}
> +
> +static noinline void __init kasan_rcu_uaf(void)
> +{
> +       struct kasan_rcu_info *ptr;
> +
> +       pr_info("use-after-free in kasan_rcu_reclaim\n");
> +       ptr = kmalloc(sizeof(struct kasan_rcu_info), GFP_KERNEL);
> +       if (!ptr) {
> +               pr_err("Allocation failed\n");
> +               return;
> +       }
> +
> +       global_ptr = rcu_dereference_protected(ptr, NULL);
> +       call_rcu(&global_ptr->rcu, kasan_rcu_reclaim);
> +}
> +
>  static int __init kmalloc_tests_init(void)
>  {
>         /*
> @@ -839,6 +868,7 @@ static int __init kmalloc_tests_init(void)
>         kasan_bitops();
>         kmalloc_double_kzfree();
>         vmalloc_oob();
> +       kasan_rcu_uaf();
>
>         kasan_restore_multi_shot(multishot);
>
> --
> 2.18.0
>
> --
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