pstore

do debug the boot process the pstore driver is used to create a persitant storage area that survives boot.

The principle idea is:

• boot the boot image that you want to debug and write the boot log to pstore
• generate a kernel panic
• boot a recovery boot image that also has pstore enabled to analyze the log

Kernel

The following options have to be enabled in the kernel config (in both boot images)

CONFIG_PSTORE=y
CONFIG_PSTORE_CONSOLE=y
CONFIG_PSTORE_PMSG=y
CONFIG_PSTORE_RAM=y

Kernel panic

I am using the attached kernel module to create a kernel panic (modprobe the module)