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

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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

Chapter 7: Oops! Interpreting the Kernel Bug Diagnostic

Kernel code is supposed to be perfect. It mustn't ever crash. But, of course, it does on occasion... Welcome to the real world.

When userspace code hits a (typical) bug – an invalid memory access, say – the processor's Memory Management Unit (MMU), upon failing to translate the invalid userspace virtual address to a physical one (via the process context's paging tables), raises a fault. The fault handler within the kernel then takes control. It ultimately (and typically) results in a fatal signal (often, SIGSEGV) being sent to the faulting process (or thread). This, of course, has the process possibly handle the signal and terminate.

Now take exactly the same case – except that this time, the invalid memory access occurs in kernel space (in kernel mode)! Hey, that's not supposed to happen, right? True, but bugs do happen, within kernel space too. This time, the kernel fault handler...