Hi, 1) changing to msleep_interruptible() did not change the situation. 2) What is strange is that I *do* see the printk messages of kernel_init/kernel_exit, but I do not see the printk messages in the thread function, thread_function() (also before the first mslee()/msleep_interruptible() ). And they are the same printk level; I also tried with printk(KERN_ERR.. in the thread_function(), but it did not help. Any ideas what can be the problem ? I will really appreciate if somebody will try to create a kernel thread and add printk inside the kernel method and look if it does print anything, Rgs, Kevin On Tue, Feb 19, 2013 at 1:38 PM, Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> wrote:

On 02/19/2013 05:02 PM, Kevin Wilson wrote:

...

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 ?

Are you sure your settings related to logging are fine? IOW, is this the only print you are not seeing, or are you not seeing *any* printk messages?

...

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.

Try using msleep_interruptible().

Regards, Srivatsa S. Bhat

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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