Re: 2f47e7e19f ("x86/mm/kaiser: Use PCID feature to make user and .."): WARNING: CPU: 0 PID: 1 at mm/early_ioremap.c:114 __early_ioremap

[Dave Hansen]

On 11/27/2017 02:18 AM, Ingo Molnar wrote:
> Any ideas about this bug?

I suspect that it's not bisected perfectly.  I did some testing with
that config and it pretty much boots or crashes randomly.

Booting in a VM on a CPU without PCID support gets crashes in early
userspace, which has tended to be a TLB flushing problem.  I'll narrow
it down some more today.