Overriding functionality with modules in Linux kernel

Question

Without getting into the details of why, I\'m looking for a clean (as possible) way to replace kernel functions and system calls from a loadable module. My initial

Answer 1

Since you want to only log the calls (i.e. you will not actually override them), and a small amount of changes to the kernel code is acceptable, the cleanest way would be to add a hook to each function you are interested in (using a notifier chain or even a plain function pointer). Your module then simply registers itself to all the hooks you added (and unregisters from them when unloaded).

It is also quite possible that someone else has already done the work of adding the hooks for you.