Update ecm.c

components/drivers/usb/usbdevice/class/ecm.c

@@ -565,7 +565,8 @@ ufunction_t rt_usbd_function_ecm_create(udevice_t device)
     /* create a cdc class */
     cdc = rt_usbd_function_new(device, &_dev_desc, &ops);
     rt_usbd_device_set_qualifier(device, &dev_qualifier);
-    _ecm_eth= rt_malloc(sizeof(struct rt_ecm_eth)); 
+    _ecm_eth= rt_malloc(sizeof(struct rt_ecm_eth));
+    RT_ASSERT(_ecm_eth != RT_NULL);
     rt_memset(_ecm_eth, 0, sizeof(struct rt_ecm_eth));
     cdc->user_data = _ecm_eth;