Ubuntu
unity-control-center package

unity-control-center crashed with SIGSEGV in g_variant_lookup_value()

Bug #1283297 reported by Scott Sweeny
12
This bug affects 2 people
Affects Status Importance Assigned to Milestone
unity-control-center (Ubuntu)
Fix Released
High
Unassigned

Bug Description

This crash occurred after my laptop had failed to set the proper resolution on an external monitor and I was fiddling with the Displays screen to try to get it to re-detect.

ProblemType: Crash
DistroRelease: Ubuntu 14.04
Package: unity-control-center 14.04.3+14.04.20140220.1-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-11.31-generic 3.13.3
Uname: Linux 3.13.0-11-generic x86_64
ApportVersion: 2.13.2-0ubuntu5
Architecture: amd64
CurrentDesktop: Unity
Date: Fri Feb 21 18:53:25 2014
ExecutablePath: /usr/bin/unity-control-center
InstallationDate: Installed on 2010-10-11 (1229 days ago)
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release amd64 (20101007)
ProcCmdline: unity-control-center
ProcEnviron:
 PATH=(custom, user)
 LANGUAGE=en_US
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x7f06d1492e8a <__strcmp_ssse3+26>: movlpd (%rsi),%xmm2
 PC (0x7f06d1492e8a) ok
 source "(%rsi)" (0x00000000) not located in a known VMA region (needed readable region)!
 destination "%xmm2" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: unity-control-center
StacktraceTop:
 g_variant_lookup_value () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
 g_variant_lookup () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/unity-control-center-1/panels/libdisplay.so
 ?? () from /usr/lib/x86_64-linux-gnu/unity-control-center-1/panels/libdisplay.so
 ?? () from /usr/lib/x86_64-linux-gnu/unity-control-center-1/panels/libdisplay.so
Title: unity-control-center crashed with SIGSEGV in g_variant_lookup_value()
UpgradeStatus: Upgraded to trusty on 2013-12-15 (68 days ago)
UserGroups: adm admin cdrom dialout libvirtd lpadmin plugdev sambashare sbuild vboxusers
usr_lib_unity-control-center:
 activity-log-manager 0.9.7-0ubuntu10
 deja-dup 29.5-0ubuntu2
 gnome-control-center 1:3.6.3-0ubuntu50
 gnome-control-center-unity 1.3+14.04.20140117-0ubuntu1

Related branches

lp:~hikiko/unity-control-center/unity-control-center.race-cond-empty-monitor-name
PS Jenkins bot (community): Approve (continuous-integration)
Sebastien Bacher: Pending requested
Diff: 47 lines (+14/-4)
1 file modified
panels/display/cc-display-panel.c (+14/-4)
Revision history for this message
Scott Sweeny (ssweeny) wrote :
Revision history for this message
Apport retracing service (apport) wrote :

StacktraceTop:
 g_variant_lookup_value (dictionary=dictionary@entry=0x4122e70, key=key@entry=0x0, expected_type=expected_type@entry=0x3f1d010) at /build/buildd/glib2.0-2.39.90/./glib/gvariant.c:1022
 g_variant_lookup (dictionary=0x4122e70, key=key@entry=0x0, format_string=format_string@entry=0x7f06b21f7500 "i") at /build/buildd/glib2.0-2.39.90/./glib/gvariant.c:948
 rebuild_ui_scale (self=0x28165c0) at cc-display-panel.c:632
 rebuild_gui (self=0x28165c0) at cc-display-panel.c:974
 on_output_event (area=0x2425d60, event=0x7ffff87c3440, data=0x4109b00) at cc-display-panel.c:1934

Revision history for this message
Apport retracing service (apport) wrote : Stacktrace.txt
Revision history for this message
Apport retracing service (apport) wrote : StacktraceSource.txt
Revision history for this message
Apport retracing service (apport) wrote : ThreadStacktrace.txt
Changed in unity-control-center (Ubuntu):
importance: Undecided → Medium
tags: removed: need-amd64-retrace
Adolfo Jayme Barrientos (fitojb)
information type: Private → Public
Revision history for this message
Sebastien Bacher (seb128) wrote :

Hey Eleni, that seems a segfault in the new code you added for the UI scale, could you have a look to it?

Changed in unity-control-center (Ubuntu):
assignee: nobody → Eleni Maria Stea (hikiko)
importance: Medium → High
Revision history for this message
Eleni Maria Stea (hikiko) wrote :

Hello, thanks for reporting it, I am getting a look at it right now!

Revision history for this message
Eleni Maria Stea (hikiko) wrote :

I didn't manage to fully reproduce the bug, but from what I've seen in Scott's backlog, the key (which is the monitor name) was empty. That means that for some reason his monitor was not detected correctly at a previous stage. I've fixed the display code to take into account the race condition where the monitor name is NULL, so now you should see a warning instead of a segfault. Could you please take some time to verify that the branch above works for you and you don't get the segmentation fault anymore?
Thank you!

Eleni Maria Stea (hikiko)
Changed in unity-control-center (Ubuntu):
status: New → In Progress
Eleni Maria Stea (hikiko)
Changed in unity-control-center (Ubuntu):
status: In Progress → Fix Committed
assignee: Eleni Maria Stea (hikiko) → nobody
Revision history for this message
Sebastien Bacher (seb128) wrote :

The issue should be fixed in that update
https://launchpad.net/ubuntu/+source/unity-control-center/14.04.3+14.04.20140226-0ubuntu1

Changed in unity-control-center (Ubuntu):
status: Fix Committed → Fix Released
no longer affects: unity-control-center
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