Just a practice
make
make test_dd
make test_program
https://blog.sourcerer.io/writing-a-simple-linux-kernel-module-d9dc3762c234 https://stackoverflow.com/questions/5970595/how-to-create-a-device-node-from-the-init-module-code-of-a-linux-kernel-module https://stackoverflow.com/questions/21767061/linux-kernel-module-character-device-permissions