Re: x86/microcode/intel: Division by zero panic in 4.9.79 and 4.4.114

From: Rolf Neugebauer
Date: Thu Feb 08 2018 - 11:26:04 EST


On Thu, Feb 8, 2018 at 2:53 PM, Borislav Petkov <bp@xxxxxxxxx> wrote:
> On Thu, Feb 08, 2018 at 01:55:48PM +0000, Rolf Neugebauer wrote:
>> On the 4.4 kernel, 1f161f67a272c ("x86/microcode: Do the family check
>> first") does not apply cleanly. Looks like it relies on 309aac77768c0
>> ("x86/microcode: Decrease CPUID use") and 7a93a40be23e5
>> ("x86/microcode: Remove local vendor variable") as well. These don't
>> apply cleanly either.
>
> It figures. The backporting game is hm, well, a fun one. :-)
>
>> Should I just manually backport the functionality of 1f161f67a272c?
>
> Yeah, try that first.

Here it is below (same disclaimer about crappy mail client). If Boris
is fine with the changes, Greg, I can send it properly with "git
send-email" if needed.

Rolf