scheduler (sched_4bsd) questions

[John Baldwin]

On Monday 04 October 2004 11:12 pm, Stephan Uphoff wrote:
> On Mon, 2004-10-04 at 14:49, Peter Holm wrote:
> > On Mon, Oct 04, 2004 at 01:34:38PM -0400, Stephan Uphoff wrote:
>
> ---- snip ----
>
> > > - but my time budget is limited and Peter has an interesting bug left
> > > that has priority.
> >
> > I'm not closer to being able to create this panic in a controlled way.
> > After a whole day of different tests I finally got this panic:
> > http://www.holm.cc/stress/log/cons81.html. The trigger seems to be one
> > particular Java applet, but it is not easily reproduceable.
> >
> > - Peter
>
> ---- snip ----
>
> I found a race condition in sleepq_catch_signals / sleepq_resume_thread
> that may cause sleepq_resume_thread to add a thread to the run queue
> that is already there.

Note that setrunnable() checks the thread state and doesn't call setrunqueue 
if the thread is already on the runqueue (see the TDS_RUNQ case in the switch 
statement).  Is this what you are referring to?

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org