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References: <20230518145544.1722059-1-Liam.Howlett@oracle.com> <20230518145544.1722059-34-Liam.Howlett@oracle.com>
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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Sun, 2 Jul 2023 20:20:26 +0200
Message-ID: <CAMuHMdV4T53fOw7VPoBgPR7fP6RYqf=CBhD_y_vOg53zZX_DnA@mail.gmail.com>
Subject: Re: [PATCH v4 33/35] maple_tree: Update testing code for mas_{next,prev,walk}
To:     "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        maple-tree@lists.infradead.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@vger.kernel.org>
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Hi Liam,

On Thu, May 18, 2023 at 9:37 PM Liam R. Howlett <Liam.Howlett@oracle.com> wrote:
> Now that the functions have changed the limits, update the testing of
> the maple tree to test these new settings.
>
> Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>

Thanks for your patch, which is now commit eb2e817f38cafbf7
("maple_tree: update testing code for mas_{next,prev,walk}") in

> --- a/lib/test_maple_tree.c
> +++ b/lib/test_maple_tree.c
> @@ -2011,7 +2011,7 @@ static noinline void __init next_prev_test(struct maple_tree *mt)
>
>         val = mas_next(&mas, ULONG_MAX);
>         MT_BUG_ON(mt, val != NULL);
> -       MT_BUG_ON(mt, mas.index != ULONG_MAX);
> +       MT_BUG_ON(mt, mas.index != 0x7d6);

On m68k (ARAnyM):

    TEST STARTING

    BUG at next_prev_test:2014 (1)
    Pass: 3749128 Run:3749129

And after that it seems to hang[*].

After adding a debug print (thus shifting all line numbers by +1):

    next_prev_test:mas.index = 0x138e
    BUG at next_prev_test:2015 (1)

0x138e = 5006, while the expected value is 0x7d6 = 2006.

I guess converting this test to the KUnit framework would make it a
bit easier to investigate failures...

[*] Left the debug one running, and I got a few more:

    BUG at check_empty_area_window:2656 (1)
    Pass: 3754275 Run:3754277
    BUG at check_empty_area_window:2657 (1)
    Pass: 3754275 Run:3754278
    BUG at check_empty_area_window:2658 (1)
    Pass: 3754275 Run:3754279
    BUG at check_empty_area_window:2662 (1)
    Pass: 3754275 Run:3754280
    BUG at check_empty_area_window:2663 (1)
    Pass: 3754275 Run:3754281
    maple_tree: 3804518 of 3804524 tests passed

So the full test took more than 20 minutes...

>         MT_BUG_ON(mt, mas.last != ULONG_MAX);
>
>         val = mas_prev(&mas, 0);

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds