oh! sorry abt that... got confused btwn 'bugs'...
The kernel bug was causing gdb to fail when passing a 32bit address to the
kernel. this was causing 32 bit gdb to fail in linux_test_for_tracefork()
by always returning second_pid = 0 in the PTRACE_GETEVENTMSG call.
this resulted in linux_enable_event_reporting() not setting the PTRACE
fork options for the pid and then the thread never received a SIGSTOP.
John Engel, kernel developer, debugged and fixed this problem in the
kernel after we reported this GDB problem to him...
So, when you debug a multi-threaded app with 32bit GDB on a PPC64 system,
and you set a break point at the thread function and tried to step, you
get the message "reading register pc (#64): No such process." for example: