When does kernel accessing virtual memory cause problems I'm working with the CPU Pintos and have a question that is:

In which situations can the kernel accessing the data in virtual memory via a pointer lead to problems? And how do you avoid them?

I know that the kernel can access the virtual memory via pointers to the stack, but don't understand when errors may occur.
Same as with any program that uses pointers: dereferencing one that points nowhere sane will give grief. If in the kernel of the system, with little or no protection against accidents (and nobody who can clean up the mess afterwards), it is much worse.