Attaching gdb session to a service launched from rc.d

[Germain <germain%lanvaux.fr@localhost>]

Greetings!


I am having trouble debugging with gdb a service that I am launching 
with rc.d:

When going `attach <pid>' in gdb (running as the same user as the user 
under which the service is running.)


I get :

(gdb) attach 26536
Attaching to program: 
/home/german/work/supportTools/Emailizer/Emailizer, process 26536
ptrace: Device busy.

Is it because I incorrectly start my service? (I do a fork.)


What's crazy is:

if I launch my service manually: (going `/etc/rc.d/mail start'.)
then I can attach and inspect, but I can't change threads.

If I restart my station (and the service autostart)
then I can't even attach.


Ok maybe it's not craazy, especially for the one who would know the 
internal reasons why this is.


Anyways, all help is welcome.
I read avidly the Chapter 7 of NetBSD Guide and skimmed the PDF 
referenced in it for all occurrences of the word `user' but did not find 
an answer to my question :|.


Thank you!


--

Germain