Kernel Debugging Instruction

Setup

I used VirtualBox for Kernel Debugging, VMWare shoud be able to do the same thing.

Enter Machine Settings -> Ports -> Serial -> Enable Serial Port

Port Number: Any :)))

Port mode: Host Pipe

Connect to existing : unchecked

Path/Address: /tmp/vbox (placeholder purpose :))

Boot Linux normally, run as root

$ echo ttyS0,9600 > /sys/module/kgdboc/parameters/kgdboc

if Port Number is COM1, use ttyS0; if it is COM2, use ttyS1… etc

Return to the host machine, run

$ socat -d -d /tmp/vbox pty &

Socat will run in the background, output the debugger serial port tty.

Fetch /boot/vmlinuz , extract with extract-vmlinux (available in the Linux Source Tree)

gdb vmlinuz
(gdb) target remote /dev/ttyXXX //The one that socat outputed

Enjoy!

Notes

• You can only attach when the kernel panic, the KDB fired up

P/s: Maybe we can attach from start with boot flag kgdboc ttyS0,9600 kgdbwait?
But it is irrelevant for the purpose of this document so I won’t discuss about it here

Reference

Somewhere in the internet :< Sorry