Re: [GIT PULL] x86/topology changes for v5.3

From: Linus Torvalds
Date: Tue Jul 09 2019 - 18:00:37 EST

On Tue, Jul 9, 2019 at 2:45 PM Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> and I suspect it's the sensitive bit pinning. But I'll delve all the way.

Confirmed. Bisection says

873d50d58f67ef15d2777b5e7f7a5268bb1fbae2 is the first bad commit
commit 873d50d58f67ef15d2777b5e7f7a5268bb1fbae2
Author: Kees Cook <keescook@xxxxxxxxxxxx>
Date: Mon Jun 17 21:55:02 2019 -0700

x86/asm: Pin sensitive CR4 bits

this is on a bog-standard Intel setup with F30, both desktop and
laptop (i9-9900k and i7-8565u respectively).

I haven't confirmed yet whether reverting just that one commit is
required, or if I need to revert the cr0 one too.

I also don't have any logs, because the boot never gets far enough. I
assume that there was a problem bringing up a non-boot CPU, and the
eventual hang ends up being due to that.