On 2/22/19 4:53 AM, Andrey Konovalov wrote: > userfaultfd_register() and userfaultfd_unregister() use provided user > pointers for vma lookups, which can only by done with untagged pointers. So, we have to patch all these sites before the tagged values get to the point of hitting the vma lookup functions. Dumb question: Why don't we just patch the vma lookup functions themselves instead of all of these callers?