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

Summary

In this chapter, you learned that there are many approaches to debugging the kernel. We even categorized them in a suitable manner to help you quickly decide which to use in what situation. This was one of the key points – not every tool or technique will be useful in every scenario or situation. For example, employing a powerful memory checker such as KASAN to help find memory bugs is really useful during the development and unit testing phases but typically impossible during systems testing and production (as the production kernel will not be configured with KASAN enabled, but the debug kernel will).

You will also realize that both hardware and software constraints play a role in determining which kernel debug features can be enabled.

Further, we showed the various approaches, tools, and techniques (even at times the API or tool names) for kernel debugging categorized in several tables. This can aid you in narrowing down your armory: which of them to use in which...