Write to unrecognized MSR on Linux 5.9

I recently updated to kernel 5.9 and started seeing the kernel log this, seems to be caused by throttled:

[  140.603433] msr: Write to unrecognized MSR 0x1a2 by python3
               Please report to x86@kernel.org
[  140.603516] msr: Write to unrecognized MSR 0x64b by python3
               Please report to x86@kernel.org

The article here seems to suggest these logs are just for information purposes and there shouldn’t be any impact on userspace programs. Nevertheless, I wanted to open this issue for tracking this and maybe putting something in the README.

Issue Analytics

State:
Created 3 years ago
Reactions:25
Comments:31 (7 by maintainers)

Top GitHub Comments

16reactions

eXt73commented, Oct 12, 2020

You have to add this to grub:

GRUB_CMDLINE_LINUX=“msr.allow_writes=on”

and update grub 😉

10reactions

bp3tk0vcommented, Oct 21, 2020

This tool started just as a simple way “to fix my own pc”. I agree with you that the right decision would be to use specific sysfs instead of raw MSRs. I would be very glad to upgrade this tool if you are going to help us by submitting the required patches for the kernel.

Cool, I’d be glad to.

So how about you send a mail to x86-at-kernel.org (replace the “-at-” with you know what 😃) with what exactly you’d like to read out/program from/to which MSRs and I’ll CC the relevant people and we’ll start the ball rolling. From initial staring, some of the info you need we export already - it’ll just need to be extended/designed properly so yours and other tools can use it too.

Thx.