Book Image

Linux Kernel Debugging

By : Kaiwan N. Billimoria
Book Image

Linux Kernel Debugging

By: Kaiwan N. Billimoria

Overview of this book

The Linux kernel is at the very core of arguably the world’s best production-quality OS. Debugging it, though, can be a complex endeavor. Linux Kernel Debugging is a comprehensive guide to learning all about advanced kernel debugging. This book covers many areas in-depth, such as instrumentation-based debugging techniques (printk and the dynamic debug framework), and shows you how to use Kprobes. Memory-related bugs tend to be a nightmare – two chapters are packed with tools and techniques devoted to debugging them. When the kernel gifts you an Oops, how exactly do you interpret it to be able to debug the underlying issue? We’ve got you covered. Concurrency tends to be an inherently complex topic, so a chapter on lock debugging will help you to learn precisely what data races are, including using KCSAN to detect them. Some thorny issues, both debug- and performance-wise, require detailed kernel-level tracing; you’ll learn to wield the impressive power of Ftrace and its frontends. You’ll also discover how to handle kernel lockups, hangs, and the dreaded kernel panic, as well as leverage the venerable GDB tool within the kernel (KGDB), along with much more. By the end of this book, you will have at your disposal a wide range of powerful kernel debugging tools and techniques, along with a keen sense of when to use which.
Table of Contents (17 chapters)
1
Part 1: A General Introduction and Approaches to Kernel Debugging
4
Part 2: Kernel and Driver Debugging Tools and Techniques
11
Part 3: Additional Kernel Debugging Tools and Techniques

Chapter 1: A General Introduction to Debugging Software

Hello there! Welcome on this journey of learning how to go about debugging a really sophisticated, large, and complex piece of software that's proven absolutely critical to big businesses as well as tiny embedded systems and everything in between – the Linux kernel.

Let's begin this very first chapter, and our journey of kernel debugging, by first understanding a little more about what a bug really is, and the origins and myths of the term debugging. Next, a glimpse at some actual real-world software bugs will (hopefully) provide the required inspiration and motivation (to firstly avoid bugs and then to find and fix bugs, of course). You will be guided on how to set up an appropriate workspace to work on a custom kernel and debug issues, including setting up a full-fledged debug kernel. We'll wrap up with some useful tips on debugging.

In this chapter, we're going to cover the following main topics:

  • Software debugging – what it is, origins, and myths
  • Software bugs – a few actual cases
  • Setting up the workspace
  • Debugging – a few quick tips