Code review comment for lp:~thomas-voss/location-service/fix-1219164

The AppArmor policies are being looked up by pid which can be a racy interface. Do the races matter to us? Will something else in the system prevent the following chain of events?

A process with pid 4242 running with AppArmor profile Foo makes a location request
A process dies from some event
B process with any pid spawns children until one has pid 4242
C process with pid 4242 running with AppArmor profile Bar receives permission to use location from previous request

It seems fairly unlikely, I'll admit, but if an attacker can chew up enough CPU time, some race conditions can become arbitrarily easy to exploit.

Thanks