How to hook a context switch??

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Date: 22 Oct 2005 02:00:55 -0700

Hi,

I have one issue and would like to get some expert advise from the
group. The below shown code snippet gives some idea about the scenario.
I have basically one function (func_1) which does a wake_up after
processing some information. Once the wake_up is executed the system
crashes.

So to debug this, i've put printks after the add_wait_queue() and
schedule function to capture the functions that gets executed with a
wake_up... but for no help.. Im unable to find the thread which gets
executed after the wake_up.

I'm wondering how to capture or debug which thread/function gets the
CPU when this wake_up has been executed... Any pointer would be highly
appreciable.

How is such a situation usually debugged?? Can such a context switching
be hooked..

/* Wait on here when we're waiting device to be ready */
wait_queue_head_t waitDev;

void func_1( struct func_arg*)
{

 /*..Do some useful work */

        wake_up(&waitDev); /* crash occurs here */
}

int sec_func (struct func_arg2 *)
{

     /* some processing work done here */
            ....
             ..
        set_current_state(TASK_UNINTERRUPTIBLE);
        add_wait_queue(&waitDev, &wait);
        spin_unlock(mutex);
        schedule();
        remove_wait_queue(&waitDev, &wait);
        spin_lock(chip->mutex);

      /* some more work is being done here */

}

Thanks in Advance,
Gromer

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