Hi, I code a kernel module which do some nop. When inserted into the kernel, the kernel will be stuck and can not reponse my keypress anymore. So, I have to reboot to get out. Why? #include <linux/init.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/kthread.h> struct task_struct *ktask = NULL; static int thread_func(void *data) { int i; while (!kthread_should_stop()){ for (i = 0; i < 1000; i++){ asm volatile ("nop\n\t"); } } return 0; } static int tst_init(void) { ktask = kthread_run(thread_func, NULL, "mythread"); return 0; } static void tst_exit(void) { if (ktask){ kthread_stop(ktask); ktask = NULL; } } module_init(tst_init); module_exit(tst_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Parmenides"); MODULE_DESCRIPTION("Something.");