Several FreeBSD programmers have raised an issue concerning AMD’s Ryzen CPU chips. Read the full article and see the original mailing list posting below.

It’s starting to look like there’s an inherent bug with AMD’s Zen-based chips that is causing issues on Unix-based operating systems, with both Linux and FreeBSD confirmed. The bug doesn’t just affect Ryzen desktop chips, but also AMD’s enterprise EPYC chips. It seems safe to assume that Threadripper will bundle it in, as well.

It’s not entirely clear what is causing the issue, but it’s related to the CPU being maxed out in operations, thus causing data to get shifted around in memory, ultimately resulting in unstable software. If the bug is exercised a certain way, it can even cause machines to reset.

Original post: https://hothardware.com/news/freebsd-programmers-report-ryzen-smt-bug-that-hangs-or-resets-machines

Mailing list post: https://svnweb.freebsd.org/base?view=revision&revision=321899

Over the weekend, we talked about an issue surrounding AMD’s Ryzen-based processors on Unix-based OSes. Today, we learn a lot more about what’s going on, as well as which products are actually affected. But first, let’s get the upside out of the way: this bug is rare, and requires very specific conditions. The vast majority of users are not going to experience an issue, but it’s at least an issue to be aware of.

Update from Hot Hardware: https://hothardware.com/news/amd-confirms-rare-ryzen-smt-bug-and-fix