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Message-ID: <86802c440809230130n44ce9dechbe6b10ffe4685ee5@mail.gmail.com>
Date: Tue, 23 Sep 2008 01:30:26 -0700
From: "Yinghai Lu" <yinghai@kernel.org>
To: "Ingo Molnar" <mingo@elte.hu>
Subject: Re: x86: fix macro with bad_bios_dmi_table
Cc: "Thomas Gleixner" <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
       "Andrew Morton" <akpm@linux-foundation.org>,
       linux-kernel@vger.kernel.org
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On Tue, Sep 23, 2008 at 1:16 AM, Ingo Molnar <mingo@elte.hu> wrote:
>
> * Yinghai Lu <yhlu.kernel@gmail.com> wrote:
>
>> need one blank tail.
>>
>> fix the crash on ingo's test box.
>
> applied to tip/x86/memory-corruption-check, thanks Yinghai!
>
>> --- a/arch/x86/kernel/setup.c
>> +++ b/arch/x86/kernel/setup.c
>> @@ -760,8 +760,8 @@ static struct dmi_system_id __initdata bad_bios_dmi_table[] = {
>>                       DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies, LTD"),
>>               },
>>       },
>> -     {}
>>  #endif
>> +     {}
>>  };
>
> i've seen such DMI crashes numerous times, caused by a missing NULL at
> the end of the table. Is there no sane way to detect or robustly avoid
> such run-off-the-end bugs?
>
> how about changing dmi_check_system(table) to a macro, which does
> something like:
>
>   __dmi_check_system(&(table), sizeof(table))

ARRAY_SIZE()

>
> and rename dmi_check_system() in drivers/firmware/dmi_scan.c to
> __dmi_check_system() and add the size parameter? That way we could
> remove the need for NULL termination and it's even a size optimization:
> it shrinks those tables a tiny bit.

# git grep dmi_system_id | grep "\[" | wc -l
62

YH