tlsdate restart does not work / can't kill processes

[Hanno Böck]

On trusty, when I do
/etc/init.d/tlsdate restart

it will start a new instance of tlsdated. However it will not end the existing instance, hence resulting in two instances of tlsdated running (which is certainly not good and will probably cause trouble).

I even can't kill the existing instances:
~ # killall tlsdated -9
tlsdated(1740): Permission denied
tlsdated(2260): Permission denied
tlsdated(2290): Permission denied

I don't really understand why there's a "Permission denied" on killall for root.

This is especially worrying in combination with bug #1448629 because I can't fix it without rebooting...