Hi, I will try to test how to create kernel threads and have write a kernel module which creates a number of kernel threads running the same function. But the results is somewhat confusing. #include <linux/kernel.h> #include <linux/kthread.h> #include <linux/delay.h> #define MAX_KTHREAD 2 struct task_struct *ktask[MAX_KTHREAD]; static int my_kthread(void *data) { int nr = *(int *)data; while (!kthread_should_stop()){ ssleep(1); printk(KERN_ALERT "This is mythread[%d].\n", nr); } return 0; } static int kthread_init(void) { int i; for (i = 0; i < MAX_KTHREAD; i++){ ktask[i] = kthread_run(my_kthread, &i, "mythread[%d]", i); } return 0; } static void kthread_exit(void) { int i; for (i = 0; i < MAX_KTHREAD; i++){ if (ktask[i]){ kthread_stop(ktask[i]); ktask[i] = NULL; } } } module_init(kthread_init); module_exit(kthread_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Shakespeare"); MODULE_DESCRIPTION("This is a test program of kthread."); The messages on the screen are: This is mythread[-929820448]. This is mythread[1]. This is mythread[-929820448]. This is mythread[1]. This is mythread[-929820448]. ... ... ... I wonder why the first thread's number is not zero rather than -929820448. Furthermore, when running again with MAX_KTHREAD == 3, the messages are: This is mythread[1]. This is mythread[2]. This is mythread[1]. This is mythread[1]. This is mythread[2]. This is mythread[1]. This is mythread[1]. This is mythread[2]. ... ... ... There should be 3 threads running, but only two of them appear. The first thread get lost.