[Bug 284229] Re: console-kit-daemon using a lot of cpu

[Whit Blauvelt]

Just had a serious runaway console-kit-daemon on Lucid! Ran my load up
into the 40-50 range with 100% CPU. Killall console-kit-daemon reduced
load to under 0.30. Is this a regression, or a newer bug?

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https://bugs.launchpad.net/bugs/284229

Title:
  console-kit-daemon using a lot of cpu

Status in ConsoleKit:
  Fix Released
Status in “consolekit” package in Ubuntu:
  Fix Released
Status in “consolekit” source package in Hardy:
  Invalid
Status in “consolekit” source package in Intrepid:
  Fix Released

Bug description:
  The use of pam-ck-connector means that consolekit registers a session for every cron or ssh session
  started. Registering a session involves creating a dbus proxy. Internally to glib these are stored in a list,
  and only removed when unref'd, but the code fails to do that. If many sessions are opened
  (high frequency cron for instance) then the list grows in length, and operations that traverse the list take
  increasing amounts of time. This can lead to consolekit taking up large amounts of CPU time.

  The fix is simply to unref the dbus proxy when we are removing the session. It is then removed from the
  internal list and causes no problems. This fix was deployed in jaunty on 2009/01/27.

  The patch for Intrepid is available in a later comment.

  TEST CASE:
    1. With an ssh server installed on the machine and keys set up so you can log in without password run
           do while `true`; do ssh localhost echo '$$'; done
        and leave it running overnight. It should lead to console-kit-daemon using a high percentage of the CPU.

  The regression potential should be low as unrefing something that is no longer used when the session
  is being removed should not be a problem.

  === Original Report ===

  Binary package hint: consolekit

  Since the last reboot, a strange and to me unknown process, console-
  kit-dae, has been using up more and more cpu.

  Right now it uses on average 10.25% cpu over 5 minutes, steadily and
  linearly (!) growing in cpu usage and have been using up 7h 36 minutes
  CPU over 7 days.

  This doesn't seem to be quite normal.

  intrepid, some week old since last update.

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