Debugging Linux Kernel in Deep Part 2

User space processes can be debugged using gdb. With gdb you can

• single-step,

• stop,

• resume,

• put break-points,

• inspect memory and variables,

• look through call stack information

What if we can use gdb on running Linux Kernel.

Problem:

How can a gdb debug running kernel as it is just a user space process.

Solution:

Client/Server Architecture

User space programs can be debugged remotely using the combination of gdbserver on the target machine and gdb on the host machine/development machine.

The Linux kernel has a GDB Server implementation called KGDB. It communicates with a GDB client over network or serial port connection

In this course we will learn:

• How to setup KGDB

• Various ways of getting the target into development machine

• Setting Breakpoints

• Printing and Setting Variables

• Using a single serial port for both kgdb and console messages

• Getting the kernel messages in gdb window

• Debugging Linux Kernel Modules (In-Tree, out of tree)

• Use of GDB Scripts present in the Linux Kernel