Linux Kernel Modules

This walks you through building loadable kernel modules from scratch: setting up the Kbuild Makefile structure, adding module parameters that show up in sysfs, exposing data through /proc or sysfs interfaces, implementing character devices with proper copy_to_user/copy_from_user handling, and signing modules for Secure Boot systems. The debugging section covers both KGDB for live kernel debugging and ftrace for function tracing, which is honestly more useful day to day than firing up a serial connection. Code examples are complete and compilable. If you're writing device drivers or need to extend kernel functionality without recompiling the whole thing, this covers the boilerplate and gotchas you'll hit in the first few hours.