Linux Kernel Development - Expanded Project Guides
Generated from:
LEARN_LINUX_KERNEL_DEEP_DIVE.md
Overview
This directory contains expanded, implementation-focused guides for each project in the Linux Kernel Development learning path. Each guide provides detailed specifications, architecture guidance, and step-by-step approaches to help you build each project from scratch.
Goal: Deeply understand Linux kernel internals—from userspace interfaces to kernel subsystems—culminating in your ability to contribute real patches to the kernel.
Why Learn Linux Kernel Development?
The Linux kernel is the foundation of Android, servers, supercomputers, embedded devices, and cloud infrastructure. Learning kernel development means:
- Understanding how computers actually work at the deepest software level
- Gaining skills that are rare and highly valued in the industry
- Joining a community that has shaped computing for 30+ years
- Being able to fix bugs, add features, and improve the system that runs the world
Project Index
| # | Project | Difficulty | Time | Key Focus |
|---|---|---|---|---|
| 1 | Kernel Interface Explorer | Beginner | Weekend | /proc and /sys pseudo-filesystems |
| 2 | System Call Tracer | Intermediate | 1-2 weeks | ptrace, syscall ABI |
| 3 | Custom Kernel Build | Intermediate | Weekend | Kconfig, QEMU, boot process |
| 4 | Kernel Module | Intermediate | 1 week | Module lifecycle, procfs, sysfs |
| 5 | Character Device Driver | Advanced | 1-2 weeks | file_operations, user/kernel transfer |
| 6 | Memory Allocator Visualizer | Advanced | 2 weeks | Buddy allocator, slab/slub |
| 7 | Scheduler Analyzer | Advanced | 1-2 weeks | CFS, vruntime, scheduling |
| 8 | Simple Filesystem | Expert | 3-4 weeks | VFS, FUSE, inodes, dentries |
| 9 | Netfilter Packet Filter | Advanced | 2 weeks | Network stack, sk_buff |
| 10 | Kernel Debugger | Advanced | 1 week | GDB, QEMU, ftrace |
| 11 | Block Device Driver | Expert | 2-3 weeks | blk-mq, request queues |
| 12 | USB Device Driver | Expert | 3-4 weeks | USB core, URBs, hot-plug |
| 13 | eBPF Tracing | Advanced | 2 weeks | BCC, bpftrace, libbpf |
| 14 | Coding Style Cleanup | Intermediate | 1-2 weeks | checkpatch.pl, git send-email |
| 15 | Bug Fix Contribution | Expert | 2-4 weeks | syzbot, crash analysis |
| 16 | Capstone: Feature Contribution | Master | 6+ months | Full development cycle |
Learning Paths
Path A: Fast Track to First Contribution (8-12 weeks)
For those who want to become a kernel contributor quickly:
- P01 - Kernel Interface Explorer (understand what kernel exposes)
- P03 - Custom Kernel Build (establish dev workflow)
- P04 - Kernel Module (learn kernel programming)
- P14 - Coding Style Cleanup (submit first patch!)
Path B: Driver Developer Track (12-16 weeks)
For those interested in hardware and drivers:
- P01 - Kernel Interface Explorer
- P03 - Custom Kernel Build
- P04 - Kernel Module
- P05 - Character Device Driver
- P10 - Kernel Debugger
- P11 - Block Device Driver or P12 - USB Device Driver
Path C: Systems Performance Track (12-16 weeks)
For those interested in performance and observability:
- P01 - Kernel Interface Explorer
- P02 - System Call Tracer
- P03 - Custom Kernel Build
- P06 - Memory Allocator Visualizer
- P07 - Scheduler Analyzer
- P13 - eBPF Tracing
Path D: Complete Mastery (4-6 months)
For those who want comprehensive kernel knowledge:
Phase 1: Foundation (2-4 weeks)
- P01 → P02 → P03
Phase 2: Kernel Programming (4-6 weeks)
- P04 → P05 → P10
Phase 3: Subsystem Deep Dives (6-10 weeks)
- Pick 2-3 from: P06, P07, P08, P09, P11, P12
Phase 4: Modern Tools & Contribution (4-6 weeks)
- P13 → P14 → P15 → P16 (Capstone)
Prerequisites
Before starting these projects, you should have:
- Strong C programming skills - Pointers, memory management, data structures
- Basic operating systems knowledge - Processes, threads, memory concepts
- Command-line proficiency - Shell scripting, common tools
- Git experience - Branching, rebasing, formatting patches
- A Linux development environment - Ubuntu/Fedora recommended
Development Environment Setup
# On Ubuntu/Debian
sudo apt install build-essential libncurses-dev bison flex libssl-dev \
libelf-dev bc dwarves git fakeroot ccache qemu-system-x86 \
debootstrap gdb
# On Fedora
sudo dnf install @development-tools ncurses-devel bison flex \
openssl-devel elfutils-libelf-devel bc dwarves git ccache \
qemu-system-x86 debootstrap gdb
# Get the kernel source
git clone https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Essential Resources
Books (Priority Order)
- “Linux Kernel Programming” by Kaiwan N. Billimoria
- “Linux Device Drivers, 3rd Edition” by Corbet, Rubini, Kroah-Hartman
- “Understanding the Linux Kernel” by Bovet & Cesati
- “The Linux Programming Interface” by Michael Kerrisk
- “Learning eBPF” by Liz Rice
Online Resources
Architecture Overview
┌─────────────────────────────────────────────────────────────────┐
│ User Space │
│ ┌──────────┐ ┌──────────┐ ┌──────────┐ ┌──────────┐ │
│ │ App │ │ App │ │ Shell │ │ Daemon │ │
│ └────┬─────┘ └────┬─────┘ └────┬─────┘ └────┬─────┘ │
│ │ │ │ │ │
│ └─────────────┴──────┬──────┴─────────────┘ │
│ │ │
│ System Call Interface │
├────────────────────────────┼────────────────────────────────────┤
│ │ Kernel Space │
│ ▼ │
│ ┌─────────────────────────────────────────────────────────┐ │
│ │ VFS (Virtual File System) │ │
│ └─────────────────────────────────────────────────────────┘ │
│ │
│ ┌──────────────┐ ┌──────────────┐ ┌──────────────────────┐ │
│ │ Process │ │ Memory │ │ Networking │ │
│ │ Scheduler │ │ Manager │ │ Stack │ │
│ │ (CFS) │ │ (slab/slub) │ │ (TCP/IP, netfilter) │ │
│ └──────────────┘ └──────────────┘ └──────────────────────┘ │
│ │
│ ┌─────────────────────────────────────────────────────────┐ │
│ │ Device Driver Framework │ │
│ │ ┌─────────┐ ┌─────────┐ ┌─────────┐ ┌─────────┐ │ │
│ │ │ Char │ │ Block │ │ Network │ │ USB │ │ │
│ │ │ Drivers │ │ Drivers │ │ Drivers │ │ Drivers │ │ │
│ │ └─────────┘ └─────────┘ └─────────┘ └─────────┘ │ │
│ └─────────────────────────────────────────────────────────┘ │
│ │
│ ┌─────────────────────────────────────────────────────────┐ │
│ │ Architecture-Specific Code (x86, ARM, RISC-V) │ │
│ └─────────────────────────────────────────────────────────┘ │
├──────────────────────────────────────────────────────────────────┤
│ Hardware │
└──────────────────────────────────────────────────────────────────┘
Project Progression Map
Week 1-2 Week 3-4 Week 5-8
┌──────────┐ ┌──────────┐ ┌──────────┐
│ P01 │────────────▶│ P03 │────────────▶│ P04 │
│Interface │ │ Build │ │ Module │
│Explorer │ │ Kernel │ │ │
└──────────┘ └──────────┘ └────┬─────┘
│ │
│ ▼
│ ┌──────────┐
│ │ P05 │
│ │ CharDev │
└──▶ P02 (optional) │ Driver │
System Call └────┬─────┘
Tracer │
▼
┌─────────────────┴─────────────────┐
│ Choose Path │
├───────────┬───────────┬───────────┤
▼ ▼ ▼ ▼
┌────────┐ ┌────────┐ ┌────────┐ ┌────────┐
│ P06 │ │ P08 │ │ P09 │ │ P11 │
│ Memory │ │ FS │ │Netfiltr│ │ Block │
└────────┘ └────────┘ └────────┘ └────────┘
│ │ │ │
└───────────┴───────────┴───────────┘
│
▼
┌──────────────────┐
│ P14: First Patch │
│ P15: Bug Fix │
│ P16: Feature │
└──────────────────┘
Happy kernel hacking!