Re: [PATCH v2 8/8] x86/debug: Remove the historical junk

From: Andy Lutomirski
Date: Sun Aug 23 2020 - 19:11:36 EST


On Fri, Aug 21, 2020 at 3:21 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> Remove the historical junk and replace it with a WARN and a comment.
>
> The problem is that even though the kernel only uses TF single-step in
> kprobes and KGDB, both of which consume the event before this,
> QEMU/KVM has bugs in this area that can trigger this state so we have
> to deal with it.

Almost acked by me.

If you make the change I suggested earlier, then the ->debugreg6
garbage can actually die.

--Andy