Kernel panic on interrupts

Hi all,
I have been working on this following problem for a while and I'm
getting nowhere.

I am using single-board computer (SBC) running White Dwarf Linux v2.0
with the following details:

Kernel:             v2.4.20
White Dwarf Linux:    v2.0
gnu:                v3.3

I have written a kernel module to react on an external hardware
interrupt that will occur at e.g. IRQ 7 line. The idea is then my
application code could wait for an interrupt (perform an
ioctl(WAIT_ON_INTERRUPT)) and react to it.

The basic structure of this module is given below:

MyModule.o
------------------

wait_queue_head_t int_queue;

__init initModule()
{
    …..
    proper initialization, etc
    ….

//register the interrupt handler
request_irq(IRQ7,myHndlr, PORTNAME,NULL)
    
    //initialize the queue head
    init_waitqueue_head(&int_queue);
}

myHndlr()
{
    //re-wake the interrupt if asleep
wake_up_interruptible(&int_queue);
}

myIoclt()
{
    //re-init the queue head
init_waitqueue_head(&int_queue);
    
    //now wait for the interrupt
interruptible_sleep_on(&int_queue);
}


And I compiled this module using proper flags such as _MODULE _KERNEL
etc....


I know the above module coupled with my application worked very well
with kernel 2.2.20.

PROBLEM
-------
When I recently moved to kernel 2.4.20, I get a kernel panic (Oops
screen dump) every time I get the interrupt occurring. Hence, when
interrupt occurs the trace jumps to myHndlr() and kernel panic occurs
at the point of wake_up_interruptible(&int_queue);
 

What could this be?

Why did the identical module worked for 2.2.20 and not for 2.4.20?? (I
made sure I used the proper lib for 2.4.20 when compiling the
MyModule.o)

I have noticed slight variation of the code in /kermel/sched.c between
2.2.20 & 2.4.20, where these functions wake_up_interruptible() etc)
are defined.

Could it also be as a result of implementation of softirq functions.
Should I enable Softirq?

I tried using cpu_raise_softirq() within MyModule.o. The module
compiled correct but when I load into the kernel, I get a lot of
unresolved symbols. What about ksoftirqd_CPU0, is this interfering
with the system?

Any help in this matter is appreciated.

Regards,
Nejhdeh Ghevondian