at - atrun utility bug on 10.0

[Konstantin Belousov]

On Sun, Oct 19, 2014 at 10:53:35AM -0700, Jim Pazarena wrote:
> I find that while a job is running via the at facility, that is,
> atrun has executed it, every subsequent execution of atrun (via
> cron) STAYS running while the original program (executed by atrun)
> is still active.
> 
> Generally, according to the docs, atrun is executed every 5 minutes
> */5 * * * * within /etc/crontab
> I always modify this to * * * * * for more prompt at execution.
> 
> I have jobs submitted via 'at' which tend to run for several hours
> sometimes even all day.
> If I do a 'ps wwax' I could see dozens, hundreds, even thousands
> of "atrun" running.
> When the original job completes all the "atrun"s disappear.
> I noticed this on 10.0, where on 9.1 it simply does not happen.
> 
> It is my feeling that the atrun on 10.0 is either being held up by
> a lock fyl, an flock, or something else which is blocking its
> normal termination when there is an empty queue, or rather when
> there is an item in the queue which is already being tended to
> by another process.
> 
> I would think that the general */5 granularity of atrun, along with
> most jobs NOT running for multiple hours tends to obfuscate this
> (what I think is a) bug. And most people looking at an wwax would
> skip past it without giving it any thought.
> 
> If anyone could confirm that I am not going insane, I would file a
> bug report thru normal channels. Of course, I may be going insane
> regardless of THIS email :-)

I doubt that port people can help you.

What version of FreeBSD do you run, exactly ?  It is 10.0 or stable/10 ?

It seems that your observations are sound, and your trouble is caused
by HEAD r251625.  OTOH, it seems that HEAD r264617, merged to stable/10
as r265368, fixed something which is described very similar to the bug
you hit.