Index: sys/amd64/amd64/pmap.c
===================================================================
--- sys/amd64/amd64/pmap.c
+++ sys/amd64/amd64/pmap.c
@@ -4286,6 +4286,7 @@
 	pml5_entry_t *pm_pml5u;
 
 	pm_pml5u = (pml5_entry_t *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(pml5pgu));
+	pagezero(pm_pml5u);
 
 	/*
 	 * Add pml5 entry at top of KVA pointing to existing pml4 pti