Comment 43 for bug 963106

You didn't answer my question in #42 above.

Type "man null" to learn how /dev/null works.

The ps command produced an error message. Assuming that it wasn't
mis-typed, that means that the modem-manager process wasn't running,
which is the correct result. That's also consistent with last line in
the modemmanager.log that you attached.

I suspect that your problem could be that modemmanager simply hasn't had
time to complete the shutdown process before umountroot is run. Since
modemmanager is an upstart job, sendsigs doesn't kill it.

I've seen no evidence that your problem is a network-manager bug. If I
were you, I would open a new bug report using ubuntu-bug, probably
against upstart.