Kernel programming is often seen as a black magic. In Arthur C Clarke’s sense, it probably is. The Linux kernel is quite different from its user space: many abstractions are waived, and you have to take extra care, as a bug in you code affects the whole system. There is no easy way to do floating-point maths, the stack is fixed and small, and the code you write is always asynchronous so you need to think about the concurrency. Despite all of this though, the Linux kernel is just a very large and complex C program that is open for everyone to read, learn and improve, and you too can be a part of it.