Rmmod hangs and the module is still loaded - why ?

["Ian Brown" <ianbrn@xxxxxxxxx>]

Helllo,


  I tried writing a simple kernel module which starts a kernel thread.
	
When I perform insmod to this module, I see that the kernel thread is started
and enters "sleep" mode (I see it by "ps -aux"). When I try to remove
the module by "rmmod" it hangs. Trying "rmmod -f" gives an error:
"ERROR: Removing 'kthread1': Device or resource busy"
and the module is **not** removed.
	
Any idea what am I missing here ?
	
should I add/change something in the cleaning up procedure ?
The code is here below; it is short (80 lines); Any help will
be more than welcomed.

---

#include <linux/version.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kmod.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/wait.h>


struct task_struct *p;

static DECLARE_WAIT_QUEUE_HEAD(wq);

static int myKernlThread(void *arg)
{
	int flag=1;
	allow_signal(SIGKILL);
	allow_signal(SIGTERM);	
	allow_signal(SIGINT);
	wait_event_interruptible(wq,flag==0);

	return 0;
}


int init(void)
{
	void *data;
	p = kthread_run(myKernlThread,data,"myKTernelThread");

	if (IS_ERR(p))
		{
		printk("could not create thread\n");
		return -1;
		}
	return 0;
}

static int __init kthread_init(void)
 {
	 init();
	 return 0;

 }

 //////////////////////////////////////////////////////////////////////////////

 static void __exit kthread_exit(void)
 {
	 if (p)
		 kthread_stop(p);
	 p=NULL;
 }


 module_init(kthread_init)
 module_exit(kthread_exit)


 MODULE_AUTHOR("IB");
 MODULE_DESCRIPTION("kthread test module");
 MODULE_LICENSE("GPL");

Regards,
Ian

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