diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index a446869..3326373 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4669,6 +4669,14 @@
 }
 
 struct page * __weak
+follow_huge_pd(struct vm_area_struct *vma,
+	       unsigned long address, hugepd_t hpd, int flags, int pdshift)
+{
+	WARN(1, "hugepd follow called with no support for hugepage directory format\n");
+	return NULL;
+}
+
+struct page * __weak
 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 		pmd_t *pmd, int flags)
 {