https://bugs.winehq.org/show_bug.cgi?id=51152
--- Comment #12 from Paul Gofman pgofman@codeweavers.com --- (In reply to Zebediah Figura from comment #10)
I'm not immediately sure I understand how the kernel can be responsible for this. The AMD spec (volume 4 ยง 4.5.3) says "When a null selector is loaded into FS or GS, the contents of the corresponding hidden descriptor register are not altered."
Yes, I read that as well but that's not what I see. I can imagine some ways how kernel can affect that. The only way I see to find that out is to dig the kernel code if there is anything about that.
Why I even think of some kernel-controlled quirk rather than a CPU bug is I don't immediately see how Windows would handle such thing nicely, while the test succeeds on Windows on the same AMD machine here.