Solve a complex exit race introduced with thread_lock:

 - Add a count of exiting threads, p_exitthreads, to struct proc.
 - Increment p_exithreads when we set the deadthread in thread_exit().
 - When we thread_stash() a deadthread use an atomic to drop the count.
 - Spin until the p_exithreads count reaches 0 in thread_wait().
 - Lock the last exiting thread momentarily to be certain that it has
   exited cpu_throw().
 - Restructure thread_wait().  It does not need a loop as there will only
   ever be one thread.

Tested by:	moose@opera.com
Reported by:	kris, moose@opera.com

0 files changed, 0 insertions, 0 deletions