unity-greeter crashed with SIGSEGV in g_object_unref()

Bug #850937 reported by Andreas Schultz on 2011-09-15
This bug affects 27 people
Affects Status Importance Assigned to Milestone
unity-greeter (Ubuntu)

Bug Description

same a LP: 834686 but with new unity-greeter-0.8

Sorry for duplicate report, but apport would not let me submit a back-trace for the old bug

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: unity-greeter 0.0.8-0ubuntu1
ProcVersionSignature: Ubuntu 3.0.0-11.17-generic 3.0.4
Uname: Linux 3.0.0-11-generic x86_64
ApportVersion: 1.23-0ubuntu1
Architecture: amd64
CrashCounter: 1
Date: Thu Sep 15 15:34:36 2011
ExecutablePath: /usr/sbin/unity-greeter
ProcCmdline: unity-greeter
 PATH=(custom, no user)
 Segfault happened at: 0x7f3d2d295a30: mov (%rdi),%rax
 PC (0x7f3d2d295a30) ok
 source "(%rdi)" (0x00000000) not located in a known VMA region (needed readable region)!
 destination "%rax" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: unity-greeter
 ?? () 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_object_unref () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
 ?? ()
 ?? ()
Title: unity-greeter crashed with SIGSEGV in g_object_unref()
UpgradeStatus: Upgraded to oneiric on 2011-07-05 (72 days ago)

Andreas Schultz (aschultz) wrote :
visibility: private → public
Dmitry Shachnev (mitya57) wrote :

Robert asked to open a NEW bug, unmarking.

This crash has the same stack trace characteristics as bug #834686. However, the latter was already fixed in an earlier package version than the one in this report. This might be a regression or because the problem is in a dependent package.

tags: added: regression-retracer

 g_settings_backend_unsubscribe (backend=0x0, name=0x0) at /build/buildd/glib2.0-2.29.90/./gio/gsettingsbackend.c:859
 g_settings_finalize (object=0x14954f0) at /build/buildd/glib2.0-2.29.90/./gio/gsettings.c:555
 g_object_unref (_object=0x14954f0) at /build/buildd/glib2.0-2.29.90/./gobject/gobject.c:2746
 settings_daemon_configure (self=<optimized out>) at settings-daemon.c:277
 settings_daemon_start_co (_data_=0x1493d90) at settings-daemon.c:155

Changed in unity-greeter (Ubuntu):
importance: Undecided → Medium
tags: removed: need-amd64-retrace
Launchpad Janitor (janitor) wrote :

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

Changed in unity-greeter (Ubuntu):
status: New → Confirmed
Andreas Schultz (aschultz) wrote :

could the importance on this bug be changed to 'High', please?

According to https://wiki.ubuntu.com/Bugs/Importance:

High: A bug which fulfills one of the following criteria:
 - Has a severe impact on a small portion of Ubuntu users (estimated)
 - Makes a default Ubuntu installation generally unusable for some users

This bug renders graphical login unusable and a novice user will IMHO have a hard time finding a workaround. So it should fulfill above criteria.

Changed in unity-greeter (Ubuntu):
importance: Medium → High
Andreas Schultz (aschultz) wrote :

Found a solution for my setup. Root cause was an inconsistent installation, so I blame it at the package managements failure to clean up its own mess.

Anyhow, unity-greeter needs gnome-settings-daemon (or something along that line), I am actually having at xubuntu install without that.

My solution:
 - purged everything unity and lightdm (dpkg --purge --force-all ...)
 - remove /etc/lightdm, /var/lib/lightdm and /var/log/lightdm
 - reinstalled lightdm (apt-get -f install)
 - fix ownership of /var/log/lightdm (needs to be owned by lightdm otherwise x-0-greeter.log can't be written ... is anyone actually testing that stuff?)
 - and finally change 'greeter-session' in /etc/lightdm/lightdm.conf to lightdm-gtk-greeter.

Torsten Geiler (togeil) wrote :

Update from 11.4 to 11.10 mythbuntu installation.
Now no x, endless crash loop.

Changed in unity-greeter (Ubuntu):
assignee: nobody → Torsten Geiler (togeil)

Update from Xubuntu 11.04 to 11.10: same problem, endless crash loop.

Fix: change 'greeter-session' in /etc/lightdm/lightdm.conf to lightdm-gtk-greeter

So, only the last step Andreas proposes is necessary. Unity-greeter segfaults, so just use lightdm-gtk-greater, and you're done.
Please fix this, a lot of Xubuntu-users will be thankful. It's just a simple conf-File that needs to be fixed, and this bug renders Xubuntu unusable. (It took me several days to pin it down.)

Richard Hansen (rhansen) on 2012-02-13
Changed in unity-greeter (Ubuntu):
assignee: Torsten Geiler (togeil) → nobody
Richard Hansen (rhansen) wrote :

These crashes in unity-greeter started happened to me on my x86_64 Oneiric machine. Possibly coincidentally, wine1.3 stopped working for me at about the same time (I think). These problems started after I uninstalled some unused *:i386 packages. As suggested in bug #852101, I ran the following to fix wine:

    sudo apt-get install --reinstall libc6-i386

Now wine works, and oddly so does unity-greeter. Is this coincidence, or does unity-greeter execute some 32-bit code that is affected by bug #852101?

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