RE: [BUG] dmi_scan_machine uses uninitialized address on x86 / EFI

From: Thomas Jourdan
Date: Wed Feb 25 2009 - 04:37:50 EST


Hi guys

The bug is not critical. Vanilla kernel works fine without the patch, except for the DMI sysfs stuffs.

Without the patch, if CONFIG_DMI is enabled, I got the "DMI not present or invalid." error message on boot. Then later, if CONFIG_DMIID is enabled, DMI system identification informations won't be exported via sysfs to userspace. The /sys/class/dmi/id entry is not present.

Regards,
Thomas

-----Message d'origine-----
De : H. Peter Anvin [mailto:hpa@xxxxxxxxx]
Envoyà : mar. 24 fÃvrier 2009 22:12
à : Thomas Jourdan
Cc : linux-kernel@xxxxxxxxxxxxxxx; Huang Ying; Peter Jones; Yinghai Lu
Objet : Re: [BUG] dmi_scan_machine uses uninitialized address on x86 /
EFI


Thomas Jourdan wrote:
>
> On x86/EFI platforms, if efi_enabled is true, the dmi_scan_machine function
> fails, even if valid DMI table is present. In the setup_arch function,
> efi_init is called after dmi_scan_machine. But this is efi_init which will
> initialize the smbios address, needed by dmi_scan_machine.
>
> This leads to dmi_scan_machine ioremapping physical address 0, instead of
> the address provided by the EFI system table. The following patch fixes the
> problem.
>

Hi Thomas,

What is the concrete manifestation of the bug (i.e. how critical is it?)
We are late in the 2.6.29-rc cycle, and this patch seems to have some
risk associated with it.

Huang, Peter, Yinghai: any opinions?

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.


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