On Sat, Feb 23, 2019 at 12:06 AM Dave Hansen <dave.hansen@xxxxxxxxx> wrote: > > 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? That might be a working approach as well. We'll still need to fix up places where the vma fields are accessed directly. Catalin, what do you think?