upstart user session leaks all the dbus events it receives

[Michael Blennerhassett]

[Impact]

The unity-panel-service process has been caching D-Bus messages sent from upstart, effectively leaking memory. The solution replaces the offending code with a single upstart event emission.

[Test Case]

0. Make sure there is a user session job with a dbus rule (eg unity-greeter-session-broadcast)
1. Install and run system-load-indicator (indicator-multiload)
2. Set the update interval to 100ms
3. Now watch the memory use of init --user increase by 100kb per second
4. Also open up upstart-monitor to see all the dbus messages being sent

[Regression Potential]

Some kind of hidden functionality depending on upstart events sent through D-Bus to the unity-panel-service may have become disconnected. Unlikely.

[Other Info]

The fix for Ubuntu 14.04 LTS was cherry picked from the Ubuntu "Vivid Vervet" dev release where it has been in regular use for some time without apparent regression.

[Michael Blennerhassett (mjblenner)]

So, for some reason I had unity-greeter-session-broadcast installed. This has a user session dbus rule:

start on dbus BUS=system SIGNAL=StartUrl INTERFACE=com.canonical.Unity.Greeter.Broadcast OBJPATH=/com/canonical/Unity/Greeter/Broadcast

which is the only dbus rule for my user session. When I removed unity-greeter-session-broadcast, I can no longer see all the dbus messages in upstart-monitor, and init --user doesn't seem to leak any memory.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[James Troup (elmo)]

I'm seeing the same thing:

 2676 james 20 0 2200268 871620 824 S 0.0 10.8 33:24.86 init --user

[Michael Blennerhassett (mjblenner)]

This also occurs if you pass --always to upstart-dbus-bridge, so I don't think it's got anything to do with upstart events/jobs.

I suspect this is a bug in unity-panel-service. Specifically at unity/services/panel-service.c:753. It's using dbus_connection_open() when it should be using g_dbus_connection_new_...() to get the mainloop integration. Without this, upstart hangs onto the dbus messages as they aren't being read. (LP: #1235649 )

[Marco Trevisan (Treviño) (3v1n0)]

Intresting... I already was wondering if it was the case to get rid of nih_dbus from u-p-s and just using gdbus, so that seems to be the right thing to do.

[Michael Blennerhassett (mjblenner)]

Or, do what unity8 has done and get rid of the whole lot, and add

pre-start exec initctl --no-wait emit indicator-services-start

to the upstart unity-panel-service.conf

[Ben Howard (darkmuggle-deactivatedaccount)]

Same thing here...seeing init take a mild 1.6G of my ram.
 5839 ben 20 0 1876920 1.669g 1564 S 0.7 7.1 9:15.98 init

What is interesting though is that out of the three systems where I have the multiload indicator installed, it is only happening on my main work rig.

[ddalex (ddalex)]

Happens to me too - 2.2 G taken.

  3830 0.3 18.7 2596616 2282860 ? Ss Apr29 11:02 \_ init --user

Just removed unity-greeter-session-broadcast, I'll report if it still happening.

[Alexander Borodetsky (magum1977)]

I have a same problem 2GB of RAM after 24 hours!

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Adam Conrad (adconrad)]

Hello Michael, or anyone else affected,

Accepted unity into trusty-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/unity/7.2.4+14.04.20150316-0ubuntu1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Launchpad Janitor (janitor)]

This bug was fixed in the package unity - 7.2.4+14.04.20150316-0ubuntu1

---------------
unity (7.2.4+14.04.20150316-0ubuntu1) trusty; urgency=medium

  [ Andrea Azzarone ]
  * Avoid running potentially dangerous code paths when the screen is
    locked. (LP: #1410582)
  * Ungrab the shoutdown dialog as soon as possible. (LP: #1398287)
  * Use COMPIZ_METAKEY where needed. (LP: #1363534)
  * disabled Pointer Barriers during lockscreen (LP: #1401911)
  * disabled markup for VolumeLauncherIcon quicklist menu items (LP:
    #1413411)
  * enable Dash, Hud, and session dialogs over full screen window (LP:
    #1159249, #860970, #1413773, #1404486)
  * made unity unlockable if user is in nopsswdlogin group (LP:
    #1413790)
  * skipped the animation of BGHash on startup to prevent unwanted fade-
    in (LP: #1241757)

  [ Luke Yelavich ]
  * extended accessible exploration of the Dash dynamic content (LP:
    #1066157)

  [ Marco Trevisan (Treviño) ]
  * MenuManager: make sure menus are always shown when mouse is over
    them or when the always-show-menus option is on (LP: #955193,
    #1390562, #1374942, #1312137)
  * PanelService: use gdbus to notfy upstart of service start/stop (LP:
    #1302955)
 -- CI Train Bot <email address hidden> Mon, 16 Mar 2015 17:30:35 +0000

[Chris J Arges (arges)]

The verification of the Stable Release Update for unity has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.