Hi Mulyadi,
Sorry for being late in replying back. I have used
schedule_timeout and it is working fine. But curious
to know what wrong is going on while using wait
queues.
I am working on kernel 2.4.20
Here is full code:
static DECLARE_WAIT_QUEUE_HEAD(wait_kernelthread);
static int print_taskinfo(void * data)
{
printk("<1>::Inside Thread Function::\n");
printk("Kernel Thread::Current Process is \"%s
\" (pid: %i) \n", current->comm,current->pid);
sprintf(current->comm,"MyTask" );
set_current_state(TASK_INTERRUPTIBLE);
void * sZombie = kmalloc(10 * sizeof(char),
GFP_KERNEL);
memset(sZombie,'\0', 10 * sizeof(char));
// Not very clear who will clean up a
temporary memory allocated for
// string literals "ZOMBIE" & "NON-ZOMBIE"...
memcpy(sZombie, "ZOMBIE", 7);
void * sNonZombie = kmalloc(15 * sizeof(char),
GFP_KERNEL);
memset(sNonZombie,'\0', 15 * sizeof(char));
memcpy(sNonZombie, "NON-ZOMBIE", 12);
struct task_struct *p ;
printk("<1>Starting Iteration\n");
for_each_process(p) {
// Iterating each element of task list.
printk ("Task List::Process PID =
%i,::PPID = %i,::State = %ld
::Zombie=%s\n",p->pid,p->parent->pid,p->state,
(p->state == TASK_ZOMBIE)? (char*)sZombie :
(char*)sNonZombie);
}
interruptible_sleep_on_timeout(&wait_kernelthread,HZ);
// Release memory allocated via kmalloc.
kfree(sZombie);
kfree(sNonZombie);
printk("<1> Exiting Thread Function::");
}
int init_module(void)
{
printk("<1>Hello Kernel World! Kernel 2.4.20\n");
printk("The current Process is \"%s \" (pid: %i)
\n", current->comm,current->pid);
kernel_thread((int (*)(void *))print_taskinfo,NULL,
CLONE_KERNEL|SIGCHLD);
return 0;
}
--- Mulyadi Santosa <mulyadi.santosa@xxxxxxxxx> wrote:
> Hi Dinesh...
>
> > static int print_taskinfo(void * data)
> > {
> > wait_queue_head_t wait;
> >
> >
> > init_waitqueue_head (&wait);
> > for (;;)
> > {
> > // do something useful here.
> > interruptible_sleep_on_timeout(&wait,
> HZ);
> > //check whether we have to break loop or
> > continue.
> > }
>
> Just a wild guess (because you don't show us your
> whole codes): task is
> woken up, but "wait" is already destroyed?
>
> And...do you really need sleep_on? If you just need
> delay, why not using
> schedule_timeout() ?
>
> Please paste the whole code as many as possible so
> we can analyze it
> better
>
> regards,
>
> Mulyadi
>
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