upstart leaks memory in init and upstart-udev-bridge

[uj__]

init and upstart-udev-bridge leak a lot of memory after starting a lot of containers.

init's memory usage grows steadily and ends up using about 80% CPU when it's using ~250 MB of RAM. upstart-udev-bridge uses about 1 GB of RAM.

The Ubuntu version is 12.04 with the lts trusty kernel. The system is fully updated as of today.

expected behaviour:
init's memory usage should remain stable, not grow over time
upstart-udev-bridge should use less than 40 MB of RAM

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: upstart 1.5-0ubuntu7.2
ProcVersionSignature: Ubuntu 3.13.0-36.63~precise1-generic 3.13.11.6
Uname: Linux 3.13.0-36-generic x86_64
ApportVersion: 2.0.1-0ubuntu17.7
Architecture: amd64
Date: Tue Sep 30 18:50:18 2014
InstallationMedia: Ubuntu-Server 12.04.4 LTS "Precise Pangolin" - Release amd64 (20140204)
MarkForUpload: True
ProcEnviron:
 LANGUAGE=en_US:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: upstart
UpgradeStatus: No upgrade log present (probably fresh install)

[uj__ (unclejacksons)]

CPU usage remains at 90% for the init process even after Docker containers aren't being started any more.