diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index a14b8a9ffb7b..ebd86677b052 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -168,22 +168,12 @@ static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
 }
 
 /*
- * Never enable huge pmd sharing on some uffd registered vmas:
- *
- * - VM_UFFD_WP and VM_UFFD_RWP VMAs, because the write protect / access
- *   tracking information is per pgtable entry.
- *
- * - VM_UFFD_MINOR VMAs, because otherwise we would never get minor faults for
- *   VMAs which share huge pmds. (If you have two mappings to the same
- *   underlying pages, and fault in the non-UFFD-registered one with a write,
- *   with huge pmd sharing this would *also* setup the second UFFD-registered
- *   mapping, and we'd not get minor faults.)
+ * Never enable huge pmd sharing on userfaultfd registered VMAs, because
+ * userfaultfd state can be tracked per VMA or per page table entry.
  */
 static inline bool uffd_disable_huge_pmd_share(struct vm_area_struct *vma)
 {
-	return vma_test_any_mask(vma,
-		mk_vma_flags_from_masks(VMA_UFFD_WP, VMA_UFFD_RWP,
-					VMA_UFFD_MINOR));
+	return vma->vm_userfaultfd_ctx.ctx;
 }
 
 /*
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 506729ebaee7..8995f4cc4e65 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6388,6 +6388,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
 			return -EEXIST;
 		}
 
+		VM_WARN_ON_ONCE(size == PMD_SIZE && hugetlb_pmd_shared(dst_pte));
 		_dst_pte = make_pte_marker(PTE_MARKER_POISONED);
 		set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte, size);