This project keeps the Linux Kernel Module Programming Guide reasonably up to date, with working examples for recent 5.x kernel versions. The guide has been around since 2001 and most copies of it on the web only describe old 2.6.x kernels.
The book can be freely accessed via https://sysprog21.github.io/lkmpg/ The original guide may be found at Linux Documentation Project.
The Linux Kernel Module Programming Guide is a free book; you may reproduce and/or modify it under the terms of the Open Software License.
Use of this work is governed by a copyleft license that can be found in the LICENSE file.
The complementary sample code is licensed under GNU GPL version 2, as same as Linux kernel.