Get the Whitepaper called Windows Kernel Exploitation Tutorial Part 5: NULL Pointer Dereference.
You can download it from the following link: https://packetstormsecurity.com/files/download/145883/winkernel-tutorialpart5.pdf
Source: https://packetstormsecurity.com/files/145883/Windows-Kernel-Exploitation-Tutorial-Part-5-NULL-Pointer-Dereference.html