dconf-service memory leak

[iroli]

(note that the component is part of GNOME and has a standing MRE then)

Impact:
The dconf-service has a leak which leads to extra memory usage over time for the session

Test Case:
Check that the dconf-service memory usage stay stable over time

Regression potential:
Limited, that's a leak fix

[iroli (roland-lezuo)]

It just (started) to happen again, I started 2 memory-demanding programs (each using 2GiB memory approx.), I do however have 8GiB memory installed.

The system froze for 2 Minutes (or so), no mouse cursor, sound stopped, sporadic hard disk activity.

Afterwards (from top):

13546 tbfg 20 0 906m 10m 3184 R 79,5 0,1 1:24.37 gnome-settings-
15316 tbfg 20 0 405m 129m 844 R 27,9 1,6 0:23.68 dconf-service

gnome-settings-daemon and dconf-service started to use (combined) 100% CPU usage and both started to eat up memory.

dmesg only shows:
[57726.545257] cherry 0003:046A:0023.0002: >control queue full
[57726.549750] cherry 0003:046A:0023.0002: >control queue full
[57726.557497] cherry 0003:046A:0023.0002: >control queue full

/var/log/syslog may have something:

Oct 22 14:03:12 tbfg-desktop rtkit-daemon[1789]: The canary thread is apparently starving. Taking action.
Oct 22 14:03:12 tbfg-desktop rtkit-daemon[1789]: Demoting known real-time threads.
Oct 22 14:03:12 tbfg-desktop rtkit-daemon[1789]: Successfully demoted thread 2171 of process 2169 (n/a).
Oct 22 14:03:12 tbfg-desktop rtkit-daemon[1789]: Successfully demoted thread 2170 of process 2169 (n/a).
Oct 22 14:03:12 tbfg-desktop rtkit-daemon[1789]: Successfully demoted thread 2169 of process 2169 (n/a).
Oct 22 14:03:12 tbfg-desktop rtkit-daemon[1789]: Demoted 3 threads.
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]: [alsa-sink] alsa-util.c: snd_pcm_avail() returned a value that is exceptionally large: 406940 bytes (2306 ms).
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]: [alsa-sink] alsa-util.c: Most likely this is a bug in the ALSA driver 'snd_hda_intel'. Please report this issue to the ALSA developers.
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]: [alsa-sink] alsa-util.c: snd_pcm_dump():
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]: [alsa-sink] alsa-util.c: Soft volume PCM
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]: [alsa-sink] alsa-util.c: Control: PCM Playback Volume
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]: [alsa-sink] alsa-util.c: min_dB: -51
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]: [alsa-sink] alsa-util.c: max_dB: 0
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]: [alsa-sink] alsa-util.c: resolution: 256
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]: [alsa-sink] alsa-util.c: Its setup is:
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]: [alsa-sink] alsa-util.c: stream : PLAYBACK
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]: [alsa-sink] alsa-util.c: access : MMAP_INTERLEAVED
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]: [alsa-sink] alsa-util.c: format : S16_LE
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]: [alsa-sink] alsa-util.c: subformat : STD
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]: [alsa-sink] alsa-util.c: channels : 2
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]: [alsa-sink] alsa-util.c: rate : 44100
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]: [alsa-sink] alsa-util.c: exact rate : 44100 (44100/1)
Oct 22 14:03:12 tbfg-desktop pulseaudio[2169]...

[Launchpad Janitor (janitor)]

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

[Launchpad Janitor (janitor)]

This bug was fixed in the package d-conf - 0.14.1-0ubuntu1

---------------
d-conf (0.14.1-0ubuntu1) raring; urgency=low

  * New upstream version:
    - fix a rather substantial memory leak in dconf-service (lp: #1069474)
  * debian/patches/git_read_default_value.patch:
    - dropped, the fix is in the new version
 -- Sebastien Bacher <email address hidden> Wed, 14 Nov 2012 11:31:45 +0100

[Brian Murray (brian-murray)]

Hello iroli, or anyone else affected,

Accepted d-conf into quantal-proposed. The package will build now and be available at http://launchpad.net/ubuntu/+source/d-conf/0.14.1-0ubuntu0.1 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 change the bug tag from verification-needed to verification-done. If it does not, 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!

[Alex Thompson (alexofdoom)]

This updated package has fixed the issue for me, I haven't seen any increase in memory usage in d-conf over the past week on a computer with an uptime of a few days.

[Colin Watson (cjwatson)]

The verification of this Stable Release Update 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 regresssions.

[Launchpad Janitor (janitor)]

This bug was fixed in the package d-conf - 0.14.1-0ubuntu0.1

---------------
d-conf (0.14.1-0ubuntu0.1) quantal-proposed; urgency=low

  * New upstream version:
    - fix a rather substantial memory leak in dconf-service (lp: #1069474)
  * debian/patches/git_read_default_value.patch:
    - dropped, the fix is in the new version
 -- Sebastien Bacher <email address hidden> Wed, 14 Nov 2012 11:31:45 +0100