Comment 29 for bug 406397

Anand, there's a rather harsh workaround using a ruby script you can download here:
http://heh.fi/tmp/workaround-upstart-snafu

It worked for me, but, as I said, the approach is quite "aggressive".

Basically it forks new dummy, short-lived, processes until the PID sequence restarts. Then, when one of these subprocesses gets the "blocked" PID, it waits until upstart kills it, thus unlocking the job's state.

I didn't see any side effects, but YMMV.