What are the essential skills and knowledge for a Linux kernel developer?

1 Programming languages

The Linux kernel is mostly written in C, with some assembly and a few other languages for specific parts. You need to be proficient in C, especially the low-level features, such as pointers, memory management, data structures, and bit manipulation. You also need to be familiar with assembly, as some kernel functions are written or called in assembly for performance or compatibility reasons. Additionally, you should learn some scripting languages, such as Bash, Python, or Perl, to automate tasks, write tests, or interact with the kernel.

2 Kernel internals

The Linux kernel is a complex and modular system that manages the hardware and software resources of a computer. You need to understand how the kernel works internally, such as how it boots, schedules processes, handles interrupts, communicates with devices, implements system calls, and provides security and memory management. You also need to know how to use the kernel documentation, source code, and tools, such as Kconfig, Makefile, or Git, to navigate and modify the kernel.

3 Development tools

The Linux kernel development process involves a set of tools that help you write, compile, debug, test, and submit code. You need to be familiar with these tools, such as GCC, GDB, QEMU, KVM, Valgrind, perf, LTTng, or kcov, to build and run the kernel, find and fix errors, measure and improve performance, and analyze the kernel behavior. You also need to know how to use the Linux Foundation's kernel development workflow, such as how to use mailing lists, patch formats, coding style, and review process, to contribute to the kernel community.

4 Hardware architecture

The Linux kernel supports a wide range of hardware architectures, such as x86, ARM, MIPS, or RISC-V. You need to have a basic knowledge of the hardware architecture you are working on, such as the CPU features, instruction set, registers, memory layout, interrupt controller, or peripheral devices. You also need to know how to configure and cross-compile the kernel for different architectures, and how to use emulators or real hardware to test the kernel on various platforms.

5 Operating system concepts

The Linux kernel is an operating system that provides the core functionality and abstraction for user applications. You need to have a solid grasp of the operating system concepts, such as processes, threads, synchronization, concurrency, inter-process communication, file systems, networking, virtualization, or containers. You also need to know how the Linux kernel implements these concepts, and how they differ from other operating systems, such as Windows or MacOS.

6 Problem-solving skills

The Linux kernel development is not only about writing code, but also about solving problems. You need to have strong problem-solving skills, such as analytical thinking, logical reasoning, debugging techniques, testing methods, and design patterns. You also need to have a curious and creative mind, a willingness to learn new things, and a collaborative and respectful attitude, to tackle the challenges and opportunities of the kernel development.