Debugging gnumach

[Joan Lledó]

Hi Hurd,

recently I tried to implement ranges on memory object proxies[1]. I 
never worked on gnumach before, so as expected it failed. That's ok, but 
now I'd like to debug gnumach in order to find the issue.

The docs[2] say I can either use the built-in debugger or gdb over qemu. 
I tried kdb, but I don't know how to find the address of a local 
variable inside a function. I also tried the gdb approach, but I can't 
boot the kernel b/c I don't know how to load the modules from the qemu 
command-line ("panic: No bootstrap code loaded with the kernel!")

- How do you guys debug gnumach? gdb or kdb?

- If gdb, what command do you use?

- If kdb, how do you read the value for a local variable?


---
[1] 
http://git.savannah.gnu.org/cgit/hurd/gnumach.git/log/?h=jlledom-mem-obj-proxy
[2] 
https://www.gnu.org/software/hurd/microkernel/mach/gnumach/debugging.html