- Move the second stop() of process 'p' in issignal() to be after we send   SIGCHLD to our parent process.  Otherwise, we could block while obtaining   the process lock for our parent process and switch out while we were   in SSTOP.  Even worse, when we try to resume from the mutex being blocked   on our p_stat will be SRUN, not SSTOP. - Fix a comment above stop() to indicate that it requires that the proc lock   be held, not a proctree lock.
- Move the second stop() of process 'p' in issignal() to be after we send
  SIGCHLD to our parent process.  Otherwise, we could block while obtaining
  the process lock for our parent process and switch out while we were
  in SSTOP.  Even worse, when we try to resume from the mutex being blocked
  on our p_stat will be SRUN, not SSTOP.
- Fix a comment above stop() to indicate that it requires that the proc lock
  be held, not a proctree lock.

Reported by:	markm
Sleuthing by:	jake

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase