- Catch a machine/mutex.h -> sys/mutex.h I somehow missed. - Close a small race condition.  The sched_lock mutex protects   p->p_stat as well as the run queues.  Another CPU could change p_stat   of the process while we are waiting for the lock, and we would end up   scheduling a process that isn't runnable.
- Catch a machine/mutex.h -> sys/mutex.h I somehow missed.
- Close a small race condition.  The sched_lock mutex protects
  p->p_stat as well as the run queues.  Another CPU could change p_stat
  of the process while we are waiting for the lock, and we would end up
  scheduling a process that isn't runnable.

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