Appendix E: Testing

Testing strategies for kernel drivers.

Testing Layers

flowchart TB
    subgraph Unit["Unit Testing"]
        KUNIT["KUnit"]
    end

    subgraph Runtime["Runtime Checks"]
        KASAN["KASAN (memory)"]
        LOCKDEP["lockdep (locking)"]
        UBSAN["UBSAN (undefined)"]
    end

    subgraph Integration["Integration"]
        SELFTEST["kselftest"]
        SYZKALLER["syzkaller (fuzzing)"]
    end

    Unit --> Runtime
    Runtime --> Integration

    style Unit fill:#7a8f73,stroke:#2e7d32
    style Runtime fill:#738f99,stroke:#0277bd
    style Integration fill:#8f8a73,stroke:#f9a825

Quick Start

Tool	Purpose	Enable
KUnit	Unit tests	CONFIG_KUNIT=y
KASAN	Memory bugs	CONFIG_KASAN=y
lockdep	Lock issues	CONFIG_PROVE_LOCKING=y
UBSAN	Undefined behavior	CONFIG_UBSAN=y

Chapters

Chapter	What You’ll Learn
KUnit	Writing unit tests
Runtime Checks	KASAN, lockdep, UBSAN

Example

• KUnit Test - Example test module

Recommended Config

# Debug options
CONFIG_DEBUG_INFO=y
CONFIG_DEBUG_KERNEL=y

# Memory debugging
CONFIG_KASAN=y
CONFIG_KASAN_INLINE=y

# Lock debugging
CONFIG_PROVE_LOCKING=y
CONFIG_DEBUG_LOCK_ALLOC=y

# Undefined behavior
CONFIG_UBSAN=y

# Unit testing
CONFIG_KUNIT=y

Further Reading

• Kernel Testing Guide
• KUnit
• KASAN

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Table of contents

• E.1 KUnit
• E.2 Runtime Checks