zen_workaround.py PermissionError (Ryzen 3700U)
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Description
I'm having trouble getting the zen_workaround.py script working on my Ryzen 3700U-based laptop.
lscpu reports cpu model is "AMD Ryzen 7 3700U with Radeon Vega Mobile Gfx"
I'm using rr 5.4 as packaged by Debian (I've diffed the workaround script and it's the same as in the github repo, other than a link referencing the Zen page on the mozilla wiki rather than the github wiki).
$ sudo /usr/share/doc/rr/examples/zen_workaround.py
Traceback (most recent call last):
File "/usr/share/doc/rr/examples/zen_workaround.py", line 46, in <module>
os.write(msr, struct.pack('<q', val))
PermissionError: [Errno 1] Operation not permitted
So it's opening /dev/cpu/7/msr and seeking, but the actual write fails...
Anything obvious I'm missing?
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the reported command, /usr/share/doc/rr/examples/zen_workaround.py, and the failing write to /dev/cpu/7/msr on the Ryzen 7 3700U. Compare the Debian rr 5.4 script with the repository version and verify the failure conditions; done means the permission error has a confirmed explanation and a documented or reproducible next step.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- linux, python
- Domain
- devtools, operating-systems
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 30/100