I am writing an interrupt handler in kernel space. I have been told that a handler is not able to access user space...so is there anyway that i can "personalize" a handler routine from user space?

to be specific, I want to supply a pointer to a user space function, called "my_isr", to the handler, and let the handler call my my_isr once interrupt arrives. The fact I observe is that I passed the pointer successfully (by checking the pointer value the handler get and the actual address my_isr...they match perfectly) but once interrupt arrives, segmentation fault results and I need to reboot. Is it because my handler is calling a function from user space and it is forbidden by OS?