Hi, guys: I am reading function scull_init_module() in scull driver.I found that scull_init_module() doesn't check scull_setup_cdev()'s return value.If there will be a probem when scull_setup_cdev() failed, and then, others call scull_cleanup_module()? for (i = 0; i < scull_nr_devs; i++) { scull_devices[i].quantum = scull_quantum; scull_devices[i].qset = scull_qset; init_MUTEX(&scull_devices[i].sem); scull_setup_cdev(&scull_devices[i], i); } Best Regard ---- Rock Lee