rkernelmymoduleko

rkernelmymoduleko is a fictional Linux kernel module used as a case study in kernel development documentation. It models a small loadable kernel module (LKM) that demonstrates how kernel code interacts with user space while illustrating common risks and best practices. Because it is not a real project, it is intended for instructional use rather than production deployment.

Design and implementation: The module would register a character device at /dev/rkmko and provide a tiny interface to manage a per-instance counter. User-space programs could increment, reset, or read the counter through IOCTL commands and simple read/write operations. The code emphasizes proper synchronization with a mutex protecting the counter and correct handling of module reference counts and error paths. It follows the standard LKM lifecycle with module_init and module_exit entry points and a cleanup routine to release resources on unload.

Interface and stability: The module maintains a single global instance and uses a refcount to ensure safe unloading while users hold references. It offers minimal logging through pr_info to illustrate kernel messaging without exposing sensitive data. The design highlights kernel-space boundaries, error handling, and the need for careful memory management.

Build and distribution: In a real scenario the module would be built with an appropriate Makefile against the running kernel headers. Typical steps include make -C /lib/modules/$(uname -r)/build M=$(PWD) modules, inserting with insmod, verifying with dmesg, and removing with rmmod afterwards. The example is commonly annotated to reflect licensing, usually GPL-compatible, and to encourage compliance with kernel coding conventions.

Legacy and purpose: This article treats rkernelmymoduleko as a teaching artifact rather than a maintained software project. It is used to illustrate concepts such as dynamic loading, device interfaces, synchronization, and lifecycle management in Linux kernel modules.