Re: x86: fix macro with bad_bios_dmi_table

From: Ingo Molnar
Date: Tue Sep 23 2008 - 04:17:26 EST



* Yinghai Lu <yhlu.kernel@xxxxxxxxx> 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))

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.

Ingo
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