Index: sys/amd64/amd64/pmap.c
===================================================================
--- sys/amd64/amd64/pmap.c
+++ sys/amd64/amd64/pmap.c
@@ -2330,7 +2330,7 @@
 		pa = VM_PAGE_TO_PHYS(m) | cache_bits;
 		if ((*pte & (PG_FRAME | X86_PG_PTE_CACHE)) != pa) {
 			oldpte |= *pte;
-			pte_store(pte, pa | pg_g | X86_PG_RW | X86_PG_V);
+			pte_store(pte, pa | pg_g | pg_nx | X86_PG_RW | X86_PG_V);
 		}
 		pte++;
 	}
Index: sys/i386/i386/pmap.c
===================================================================
--- sys/i386/i386/pmap.c
+++ sys/i386/i386/pmap.c
@@ -1677,7 +1677,7 @@
 		pa = VM_PAGE_TO_PHYS(m) | pmap_cache_bits(m->md.pat_mode, 0);
 		if ((*pte & (PG_FRAME | PG_PTE_CACHE)) != pa) {
 			oldpte |= *pte;
-			pte_store(pte, pa | pgeflag | PG_RW | PG_V);
+			pte_store(pte, pa | pgeflag | pg_nx | PG_RW | PG_V);
 		}
 		pte++;
 	}