Comment 1 for bug 1377338

The cause of the corruption is believed to be an interaction between the click-system-hooks and the apparmor upstart jobs. click-apparmor will be adjusted to use a blocking lockfile to avoid the corruption. As such, the apparmor task priority can be reduced.

After discussing with the apparmor team, fixing the parser bug can (and should be done) but it more involved that the cache bug and we can't fix it in time for rtm. If the lockfile doesn't fully address this issue, we can go back to using '-n1' with xargs unconditionally in /lib/apparmor/functions.