CVS commit: src/sys/kern

["Jason R Thorpe" <thorpej%netbsd.org@localhost>]

Module Name:    src
Committed By:   thorpej
Date:           Fri Dec 28 00:15:57 UTC 2018

Modified Files:
        src/sys/kern: kern_threadpool.c

Log Message:
Fix job reference counting:
- threadpool_job_hold() no longer returns failure on overflow; it
  asserts that overflow doesn't happen.
- threadpool_job_rele() must be called with the job lock held.
- Always grab a reference count on the job in threadpool_schedule_job()
  if we're going to do any work.
- Drop that reference count directly in threadpool_job_done(); it's not
  safe to dereference the job structure after the job function has called it.
- In the overseer thread, when handing off the job to work thread, hold an
  extra reference briefly, as there's a window where we hold neither the
  pool lock or the job lock, and without this extra reference, the job could
  be snatched away.


To generate a diff of this commit:
cvs rdiff -u -r1.12 -r1.13 src/sys/kern/kern_threadpool.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.