On 11/17/22 15:23, Marco Elver wrote:
> Yes - it's the 'level != PG_LEVEL_4K'.

That plus the bisect made it pretty easy to find, thanks for the effort!

Could you double-check that the attached patch fixes it?  It seemed to
for me.

The issue was that the new "No changes, easy!" check in the suspect
commit didn't check the cpa->force_split option.  It didn't split down
to 4k and then all hell broke loose.

Oh, and I totally misread the kfence ability to tolerate partial TLB
flushes.  Sorry for the noise there!