vma_can_userfault
if (!vma_can_userfault(cur, vm_flags, wp_async))
if (!vma_can_userfault(cur, cur->vm_flags, wp_async))
VM_WARN_ON_ONCE(!vma_can_userfault(vma, vma->vm_flags, wp_async));
VM_WARN_ON_ONCE(!vma_can_userfault(vma, vm_flags, wp_async));