You're reading from Linux Kernel Debugging Leverage proven tools and advanced techniques to effectively debug Linux kernels and kernel modules

Product type Paperback

Published in Aug 2022

Publisher Packt

ISBN-13 9781801075039

Length 638 pages

Edition 1st Edition

Tools

Linux

Concepts

System Administration

Author (1):

Kaiwan N. Billimoria

View More author details

Table of Contents (17) Chapters

Preface

1. Part 1: A General Introduction and Approaches to Kernel Debugging

2. Chapter 1: A General Introduction to Debugging Software FREE CHAPTER

3. Chapter 2: Approaches to Kernel Debugging

4. Part 2: Kernel and Driver Debugging Tools and Techniques

5. Chapter 3: Debug via Instrumentation – printk and Friends

6. Chapter 4: Debug via Instrumentation – Kprobes

7. Chapter 5: Debugging Kernel Memory Issues – Part 1

8. Chapter 6: Debugging Kernel Memory Issues – Part 2

9. Chapter 7: Oops! Interpreting the Kernel Bug Diagnostic

10. Chapter 8: Lock Debugging

11. Part 3: Additional Kernel Debugging Tools and Techniques

12. Chapter 9: Tracing the Kernel Flow

13. Chapter 10: Kernel Panic, Lockups, and Hangs

14. Chapter 11: Using Kernel GDB (KGDB)

15. Chapter 12: A Few More Kernel Debugging Approaches

16. Other Books You May Enjoy

Catching concurrency bugs with KCSAN

The Kernel Concurrency Sanitizer (KCSAN) is a powerful kernel framework for helping catch data races within the Linux kernel (and modules). It was merged into the kernel in the 5.8 series (Aug 2020). It currently works on the x86_64 platform with support for ARM64 being very recent (the 5.17 kernel, March 2022).

What KCSAN does, in a nutshell

KCSAN figures out data races (if you haven't already, please first read this section: What exactly is a data race?) and reports them. In a nutshell, KCSAN treats all aligned writes up to the processor word size as atomic (regardless of whether they're plain or marked accesses). In effect, KCSAN works by checking for unmarked (or plain) reads that race with these writes (that is, any write to the same address where the unmarked read occurred)!

KCSAN is essentially a robot that (with the help of a syzbot instance), continuously scans the kernel's main branches, setting up watchpoints on...