Re: [PATCH 07/10] mm/hugetlb: tolerate uffd bits set without uffd for PROT_NONE PTEs

[Lance Yang]

On Thu, Oct 15, 2026 at 06:07:13PM +0200, David Hildenbrand (Arm) wrote:
>The whole uffd handling when a VMA is unregistered from UFFD is shaky:
>there are still some scenarios where we might have stale uffd PTE bits
>in VMAs no longer registered for UFFD, which confuses other code.
>
>Let's just tolerate that for now and simply clear the PTE bit. Add a
>TODO to really clean up any uffd leftovers when unregistering a VMA from
>userfaultfd.
>
>The handling is now more similar to what we have in handle_pte_fault().
>
>Fixes: 2d427bb01639 ("mm/userfaultfd: add RWP fault delivery and expose UFFDIO_REGISTER_MODE_RWP")
>Cc: stable@xxxxxxxxxxxxxxx
>Signed-off-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>
>---

Reviewed-by: Lance Yang <lance.yang@xxxxxxxxx>