5.1_RC4 - gdb can't attach to processes

[Lloyd Parkes <lloyd%must-have-coffee.gen.nz@localhost>]

Hi all,
I'm running NetBSD/i386 5.1_RC4 that I built a few days ago and I'm  
having some trouble with gdb. It attaches to the target process, but  
doesn't seem to know that it attached, so I can't debug my program.  
Gdb prints the message "ptrace: No such process.", but when I quite  
gdb, the process sure looks like someone has attached a debugger to it.

Has anyone seen this before or have any idea what is going on?

Here is a cut and paste of a debug session showing this behaviour.

Cheers,
Lloyd

homarid-5.1_RC4$ ps x
  PID TTY   STAT    TIME COMMAND
 7898 ttyp0 S+   0:00.02 ./poll/poll
26751 ttyp0 S+   0:00.01 receive
23354 ttyp2 O+   0:00.00 ps -x
homarid-5.1_RC4$ gdb
GNU gdb 6.5
...
This GDB was configured as "i386--netbsdelf".
(gdb) attach 26751
Attaching to process 26751
ptrace: No such process.
(gdb) bt
No stack.
(gdb) detach
(gdb) homarid-5.1_RC4$ ps x
  PID TTY   STAT    TIME COMMAND
 7898 ttyp0 S+   0:00.11 ./poll/poll
20435 ttyp0 Is   0:00.10 -bash
26751 ttyp0 ZW+  0:00.00 (receive)
 5046 ttyp2 O+   0:00.00 ps -x