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Message-ID: <c5f29a53-aae2-1d1b-9c98-5878a046d1f3@bytedance.com>
Date:   Tue, 4 Jul 2023 23:11:15 +0800
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Subject: Re: [PATCH v4 33/35] maple_tree: Update testing code for
 mas_{next,prev,walk}
To:     Geert Uytterhoeven <geert@linux-m68k.org>,
        "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>
References: <20230518145544.1722059-1-Liam.Howlett@oracle.com>
 <20230518145544.1722059-34-Liam.Howlett@oracle.com>
 <CAMuHMdV4T53fOw7VPoBgPR7fP6RYqf=CBhD_y_vOg53zZX_DnA@mail.gmail.com>
From:   Peng Zhang <zhangpeng.00@bytedance.com>
In-Reply-To: <CAMuHMdV4T53fOw7VPoBgPR7fP6RYqf=CBhD_y_vOg53zZX_DnA@mail.gmail.com>
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在 2023/7/3 02:20, Geert Uytterhoeven 写道:
> 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 took a look. The return value 5006 is correct while the
expected value is wrong. This is a problem with the test,
it is not compatible with 32-bit systems.
> 
> 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