Pull up following revision(s) (requested by pgoyette in ticket #1979):
sys/kern/kern_synch.c: revision 1.309
sys/kern/kern_exit.c: revisions 1.246, 1.247
sys/kern/kern_exec.c: revision 1.419
In execve_runproc(), update the p_waited entry for the process being
moved to SSTOP state, not for its parent.  (It is correct to update
the parent's p_nstopchild count.)  If the value is not already zero,
it could prevent its parent from waiting for the process.
Fixes PR kern/50298
--
When clearing out the scheduler queues during system shutdown, we move
all processes to the SSTOP state.  Make sure we update each process's
p_waited and the parents' p_nstopchild counters to maintain consistent
values.  Should not make any real difference this late in the shutdown
process, but we should still be consistent just in case.
Fixes PR kern/50318
--
Currently, if a process is exiting and its parent has indicated no intent
of reaping the process (nor any other children), the process wil get
reparented to init.  Since the state of the exiting process at this point
is SDEAD, proc_reparent() will not update either the old or new parent's
p_nstopchild counters.
This change causes both old and new parents to be properly updated.
Fixes PR kern/50300
--
For processes marked with PS_STOPEXIT, update the process's p_waited
value, and update its parent's p_nstopchild value when marking the
process's p_stat to SSTOP.  The process needed to be SACTIVE to get
here, so this transition represents an additional process for which
the parent needs to wait.
Fixes PR kern/50308

(snj)