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Linux Kernel Debugging

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

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Product type Paperback
Published in Aug 2022
Publisher Packt
ISBN-13 9781801075039
Length 638 pages
Edition 1st Edition
Tools
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Author (1):
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Kaiwan N. Billimoria Kaiwan N. Billimoria
Author Profile Icon Kaiwan N. Billimoria
Kaiwan N. Billimoria
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Toc

Table of Contents (17) Chapters Close

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

Panic! – what happens when a kernel panics

To conquer the beast, you must first understand it. In that spirit, let's panic!

The primary panic handling code in the kernel lies here: kernel/panic.c:panic(). The panic() function – the heart of it – receives, as parameters, a variable argument list – a printf-style format specifier and associated variables (whose values will be printed):

// kernel/panic.c
/**
*  panic - halt the system
*  @fmt: The text string to print
*
*  Display a message, then perform cleanups.
*  This function never returns.
*/
void panic(const char *fmt, ...)
{ [...]

This function should (quite obviously) never be lightly invoked; calling it implies that the kernel is in an unusable, unusable state; once called, the system effectively comes to a grinding halt.

Let's panic

Here, with a view to being empirical and experimenting (on our test VM, of...

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