Ubuntu
linux package

  1. Bug #1690085
  2. Comment #546

Comment 546 for bug 1690085

Revision history for this message
In , Michael (michael-linux-kernel-bugs) wrote :

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??