Re: [User-mode-linux-user] Need some hints on how to debug

[Jeff D. <jd...@ka...>]

ua...@al... said:
> I have read the how to on how to debug linux-uml, but I can't do the
> following:
> + a syscall 
> + bottom halves and other kernel contetxt processing
> any comment would be greatly appreciated 

This is slightly complicated because the threads are already being ptraced, so 
gdb can't attach to them.  What you do is get the thread you want to debug to 
stop where you want to debug it.  Something like this is what I do:
	printk("here I am");
	stop();

Send that thread a SIGUSR1, which tells the tracing thread to detach it.  
Attach to it with gdb.  'return' in gdb until you're out of the stop().  
You're in business.

Lars wrote some code that makes this simpler.  I haven't bothered to integrate 
it in yet.  It has the tracing thread ptrace gdb, and fake all of gdb's 
ptraces.  That would make debugging the kernel a lot more like debugging a 
normal process.

				Jeff