How to debug the /sbin/init process?

[Shawn Jin]

Hi,

How can I use GDB to debug the first user space process /sbin/init
when the kernel invokes this process?

I use BDI2000 and GDB to debug the linux kernel on an IBM Ebony board.
GDB always lose the control after the system call instruction 'sc' is
executed. Although having googled the Internet including this mailing
list for quite a while, I haven't got a clear picture on how to
instruct GDB to step into a user space process.

How do you guys debug it if there happens to be a bug in /sbin/init?

Thanks,
-Shawn.