diff --git a/sys/dev/smbus/smbus.c b/sys/dev/smbus/smbus.c
--- a/sys/dev/smbus/smbus.c
+++ b/sys/dev/smbus/smbus.c
@@ -112,6 +112,12 @@
 	return (child);
 }
 
+static void
+smbus_child_deleted(device_t dev, device_t child)
+{
+	free(device_get_ivars(child), M_DEVBUF);
+}
+
 static void
 smbus_hinted_child(device_t bus, const char *dname, int dunit)
 {
@@ -222,6 +228,7 @@
 
 	/* bus interface */
 	DEVMETHOD(bus_add_child,	smbus_add_child),
+	DEVMETHOD(bus_child_deleted,	smbus_child_deleted),
 	DEVMETHOD(bus_hinted_child,	smbus_hinted_child),
 	DEVMETHOD(bus_probe_nomatch,	smbus_probe_nomatch),
 	DEVMETHOD(bus_child_location,	smbus_child_location),