Index: sys/kern/vfs_subr.c
===================================================================
--- sys/kern/vfs_subr.c
+++ sys/kern/vfs_subr.c
@@ -3594,7 +3594,7 @@
 
 	if (vp->v_pollinfo != NULL)
 		return;
-	vi = uma_zalloc(vnodepoll_zone, M_WAITOK);
+	vi = uma_zalloc(vnodepoll_zone, M_WAITOK | M_ZERO);
 	mtx_init(&vi->vpi_lock, "vnode pollinfo", NULL, MTX_DEF);
 	knlist_init(&vi->vpi_selinfo.si_note, vp, vfs_knllock,
 	    vfs_knlunlock, vfs_knl_assert_locked, vfs_knl_assert_unlocked);
Index: sys/vm/uma_core.c
===================================================================
--- sys/vm/uma_core.c
+++ sys/vm/uma_core.c
@@ -1940,6 +1940,20 @@
 	args.dtor = dtor;
 	args.uminit = uminit;
 	args.fini = fini;
+#ifdef  INVARIANTS
+	/*
+	 * If a zone is being created with an empty constructor and
+	 * destructor, pass UMA constructor/destructor which checks for
+	 * memory use after free.
+	 */
+	if ((!(flags & UMA_ZONE_ZINIT)) && ctor == NULL && dtor == NULL &&
+	    uminit == NULL && fini == NULL) {
+		args.ctor = trash_ctor;
+		args.dtor = trash_dtor;
+		args.uminit = trash_init;
+		args.fini = trash_fini;
+	}
+#endif
 	args.align = align;
 	args.flags = flags;
 	args.keg = NULL;
Index: sys/vm/uma_dbg.c
===================================================================
--- sys/vm/uma_dbg.c
+++ sys/vm/uma_dbg.c
@@ -69,8 +69,13 @@
 
 	for (p = mem; cnt > 0; cnt--, p++)
 		if (*p != uma_junk) {
+#ifdef INVARIANTS
+			panic("Memory modified after free %p(%d) val=%x @ %p\n",
+			    mem, size, *p, p);
+#else
 			printf("Memory modified after free %p(%d) val=%x @ %p\n",
 			    mem, size, *p, p);
+#endif
 			return (0);
 		}
 	return (0);