SIGKILL and a sleeping kernel module

Kevin Wilson wkevils at gmail.com
Tue Feb 19 06:32:08 EST 2013


Hi,

Thanks about the info about ps.
This raises two new questions:
1)  The following code is a very basic kernel module (based on my
previous code, removing somethings).
I do not understand something:
I call
  /* sleep for a millisecond */
    msleep(1);
    printk("calling do_exit\n");
    msleep(60000);

In my understanding, after 1 millisecond, it should have been
available to the scheduler, and after returning to the line after
msleep(1), it should print "calling do_exit". However,
I see no such log message. Any ideas why ? can something be
added to enable this ?

2)How can I create a kernel thread so that it will be in
TASK_INTERRUPTIBLE state ? there must be a way,
since I see many kernel threads where ps shows "S" in the
status coumn.


struct task_struct *task;

int thread_function(void *data)
{
    int exit_sig = SIGKILL;

    printk("in %s\n",__func__);
    /* sleep for a millisecond */
    msleep(1);
    printk("calling do_exit\n");
    msleep(60000);
    do_exit(exit_sig);

    return 0;
}

static int kernel_init(void)
    {
    printk("in kernel_init\n");    	
    task = kthread_create(thread_function,NULL,"MY_KERNEL_THREAD");
    return 0;
}

static void kernel_exit(void)
    {
    printk("in kernel_exit\n");
    kthread_stop(task);
    }


module_init(kernel_init);
module_exit(kernel_exit);


rgs
Kevin



More information about the Kernelnewbies mailing list