Comment 547 for bug 1690085

(In reply to Michael from comment #459)
> I think this bug is mostly about the official AMD Errata 1109 "MWAIT
> Instruction May Hang a Thread".
>
> This is described here (
> https://developer.amd.com/wp-content/resources/55449_1.12.pdf ) as:
>
> "Under a highly specific and detailed set of internal timing conditions, the
> MWAIT instruction may cause a
> thread to hang in SMT (Simultaneous Multithreading) Mode."
>
> Since this is a nofix for AMD, this must be fixed by the OS. The AMD
> document states:
>
> "Suggested Workaround
> System software may contain the workaround for this erratum."
>
> So, unfortunately AMD will never solve that hardware error. I suggest they
> change the first two letters of their company name ;)
>
> This in fact leaves every linux system with a Ryzen CPU instable, so this
> should be considered serious.
>
> I didn't read a comment from any kernel developer in the history of this bug
> report. Did I overlook something?
>
> Question: Will the Linux kernel ever implement a workaround (as suggested by
> AMD??

idle=nomwait kernel option fixed all hangs for me