+static bool is_address_protected(void *p)
+{
+	struct page *page;
+	struct vmap_area *area;
+
+	if (unlikely(!is_vmalloc_addr(p)))
+		return false;
+	page = vmalloc_to_page(p);
+	if (unlikely(!page))
+		return false;
+	wmb(); /* Flush changes to the page table - is it needed? */

No.

The rest of this is just pretty verbose and seems to have been very
heavily copied and pasted.  I guess that's OK for test code, though.