diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
index a284dc5..523fece 100644
--- a/drivers/dax/dax.c
+++ b/drivers/dax/dax.c
@@ -518,6 +518,8 @@
 	phys_addr_t phys;
 	pgoff_t pgoff;
 	pfn_t pfn;
+	unsigned int fault_size = PUD_SIZE;
+
 
 	if (check_vma(dax_dev, vmf->vma, __func__))
 		return VM_FAULT_SIGBUS;
@@ -534,6 +536,16 @@
 		return VM_FAULT_SIGBUS;
 	}
 
+	if (fault_size < dax_region->align)
+		return VM_FAULT_SIGBUS;
+	else if (fault_size > dax_region->align)
+		return VM_FAULT_FALLBACK;
+
+	/* if we are outside of the VMA */
+	if (pud_addr < vmf->vma->vm_start ||
+			(pud_addr + PUD_SIZE) > vmf->vma->vm_end)
+		return VM_FAULT_SIGBUS;
+
 	pgoff = linear_page_index(vmf->vma, pud_addr);
 	phys = pgoff_to_phys(dax_dev, pgoff, PUD_SIZE);
 	if (phys == -1) {