[screen]: gnome-control-center crashed with SIGSEGV in g_type_check_instance_cast()

[Alexey Borzenkov]

Happened when I went to "Brightness & Lock" and then tried going back by clicking "All Settings". Happens reproducibly.

ProblemType: Crash
DistroRelease: Ubuntu 13.10
Package: gnome-control-center 1:3.6.3-0ubuntu33
ProcVersionSignature: Ubuntu 3.11.0-4.9-generic 3.11.0-rc7
Uname: Linux 3.11.0-4-generic x86_64
ApportVersion: 2.12.1-0ubuntu3
Architecture: amd64
Date: Sat Aug 31 21:45:30 2013
ExecutablePath: /usr/bin/gnome-control-center
InstallationDate: Installed on 2013-08-31 (0 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Alpha amd64 (20130830)
MarkForUpload: True
ProcCmdline: gnome-control-center --overview
SegvAnalysis:
 Segfault happened at: 0x7f55b141926c <g_type_check_instance_cast+28>: mov (%rax),%rdi
 PC (0x7f55b141926c) ok
 source "(%rax)" (0xaaaaaaaaaaaaaaaa) not located in a known VMA region (needed readable region)!
 destination "%rdi" ok
SegvReason: reading unknown VMA
Signal: 11
SourcePackage: gnome-control-center
StacktraceTop:
 g_type_check_instance_cast () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/control-center-1/panels/libscreen.so
 g_simple_async_result_complete () from /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
 g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
Title: [screen]: gnome-control-center crashed with SIGSEGV in g_type_check_instance_cast()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
usr_lib_gnome-control-center:
 activity-log-manager 0.9.7-0ubuntu4
 deja-dup 27.3.1-0ubuntu1
 gnome-control-center-datetime 13.10.0+13.10.20130828.2-0ubuntu1
 gnome-control-center-signon 0.1.7~+13.10.20130724.1-0ubuntu1
 gnome-control-center-unity 1.3daily13.06.14.1-0ubuntu1

[Apport retracing service (apport)]

StacktraceTop:
 g_type_check_instance_cast (type_instance=type_instance@entry=0x262d170, iface_type=38042384) at /build/buildd/glib2.0-2.37.6/./gobject/gtype.c:4008
 got_power_proxy_cb (source_object=<optimized out>, res=0x2649a40, user_data=user_data@entry=0x262d170) at cc-screen-panel.c:293
 g_simple_async_result_complete (simple=0x2649a40) at /build/buildd/glib2.0-2.37.6/./gio/gsimpleasyncresult.c:777
 complete_in_idle_cb (data=0x2649a40) at /build/buildd/glib2.0-2.37.6/./gio/gsimpleasyncresult.c:789
 g_main_dispatch (context=0x1c4fac0) at /build/buildd/glib2.0-2.37.6/./glib/gmain.c:3065

[Alexey Borzenkov (snaury)]

This probably happens because on VirtualBox I don't have power control or something, so the callback never returns, however when I click All Settings it gets cancelled and when callback fires the panel is already destroyed. Attached is an example patch that fixes this particular issue, but in general all callbacks should be fixed to check for error first and dereference user_data only on success / not being cancelled.

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "An example patch for this problem" seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issues please contact him.]

[Sebastien Bacher (seb128)]

The bug hasn't seen any activity in years and there has been no recent similar reports, the code also changed quite a lot since and it's likely the issue doesn't exist anymore. Closing, feel free to open a new report if you still get problems in recent Ubuntu versions