If you did want to try exhausting the PID space, I wrote a bash script to do just that (it runs a program with a desired PID): https://github.com/lunixbochs/me

If you did want to try exhausting the PID space, I wrote a bash script to do just that (it runs a program with a desired PID): https://github.com/lunixbochs/meta/blob/master/utils/pidrun/pidrun https://github.com/lunixbochs/meta/blob/master/utils/pidrun/... You can use it like this: ./pidrun 23000 cat It might take a few minutes if it needs to wrap around the PID space. When it's done, you'll have a cat process occupying PID 23000, which upstart might be willing to sacrifice.