unity-2d-launcher crashed with SIGSEGV in exit()

Bug Description

Starting an xubuntu session crashes unity-2d. Why is it starting anyway, when I am loggin into a xubuntu session??

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: unity-2d-launcher 4.10.0-0ubuntu1
ProcVersionSignature: Ubuntu 3.0.0-11.18-generic 3.0.4
Uname: Linux 3.0.0-11-generic i686
ApportVersion: 1.23-0ubuntu1
Architecture: i386
Date: Mon Sep 26 14:11:02 2011
ExecutablePath: /usr/bin/unity-2d-launcher
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
ProcCmdline: unity-2d-launcher
ProcEnviron:
LANGUAGE=de_CH:de
PATH=(custom, no user)
LANG=de_CH.UTF-8
SHELL=/bin/bash
SegvAnalysis:
Segfault happened at: 0x427934: mov 0x8(%edx),%edx
PC (0x00427934) ok
source "0x8(%edx)" (0xa4f67060) not located in a known VMA region (needed readable region)!
destination "%edx" ok
Stack memory exhausted (SP below stack segment)
SegvReason: reading unknown VMA
Signal: 11
SourcePackage: unity-2d
StacktraceTop:
?? () from /lib/i386-linux-gnu/libc.so.6
exit () from /lib/i386-linux-gnu/libc.so.6
?? () from /usr/lib/i386-linux-gnu/libQtGui.so.4
_XIOError () from /usr/lib/i386-linux-gnu/libX11.so.6
_XReadEvents () from /usr/lib/i386-linux-gnu/libX11.so.6
Title: unity-2d-launcher crashed with SIGSEGV in exit()
UpgradeStatus: Upgraded to oneiric on 2011年09月12日 (14 days ago)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare
XsessionErrors:
(xfwm4:1469): GLib-CRITICAL **: g_str_has_prefix: assertion `prefix != NULL' failed
(xfce4-settings-helper:1552): GLib-CRITICAL **: g_str_has_prefix: assertion `prefix != NULL' failed
(xfwm4:1469): xfwm4-WARNING **: The property '/general/double_click_distance' of type int is not supported
(xfce4-panel:1471): libxfce4ui-WARNING **: ICE I/O Error
(xfce4-panel:1471): libxfce4ui-WARNING **: Disconnected from session manager.

StacktraceTop:
__run_exit_handlers (status=1, listp=0x56d324, run_list_atexit=true) at exit.c:50
__GI_exit (status=1) at exit.c:100
qt_xio_errhandler () at kernel/qapplication_x11.cpp:781
_XIOError (dpy=0x9b20128) at ../../src/XlibInt.c:1618
_XReadEvents (dpy=0x9b20128) at ../../src/xcb_io.c:442

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

I'll try to investigate this.

Got some other bugs to attend to, so I'll leave this unassigned for the time being :-)

I cannot reproduce this. André, can you still get this?

Investigating this, I see that the KeyMonitor has a thread which watches for all keyboard events with XNextEvent. If the Xserver shuts down, XNextEvent will fail and calls _XIOError which calls any error handler if defined (to quit). Qt installs an error handler qt_xio_errhandler to print an error & quits (exit(1)). During this exit, I believe a thread isn't stopping cleanly.

This bug was fixed in the package unity-2d - 5.2.0-0ubuntu1

---------------
unity-2d (5.2.0-0ubuntu1) precise; urgency=low

[ Didier Roche ]
* New upstream release:
- Select quicklist items with just one right click (LP: #688830)
- Launcher - Dragging and dropping a running application in to the Trash
should quit the application and (if the app is pinned to the Launcher)
un-pin the application from the Launcher (LP: #870143)
- Dash - "See more..." line should be base-aligned with section header
(LP: #748101)
- right click on the dash icon should display a list of the lenses
(LP: #868452)
- Top Bar - rename the "Desktop" title in the Top Bar (displayed when no
window has focus) to "Ubuntu Desktop" (LP: #869873)
- Application title on quicklist should be bold (or more visible)
(LP: #900400)
- unity-2d-launcher crashed with SIGSEGV when opening a folder on a CD
(LP: #831868)
- unity-2d-places crashed with SIGSEGV in QScriptValue::call()
(LP: #836498)
- unity-2d-launcher crashed with SIGSEGV in geis_finish() (LP: #850893)
- unity-2d-places crashed with SIGABRT in raise() (LP: #857575)
- unity-2d-launcher crashed with SIGSEGV in exit() (LP: #859596)
- [spread] layout broken since bzr revision 799 of lp:unity-2d
(LP: #900895)
- [workspace switcher] keyboard navigation of workspace switcher broken
for accessibility (LP: #744978)
- [spread] workspace switcher performance is poor, especially on low
powered CPUs (LP: #745764)
- Launcher - the rendering of the BFB and Lens squircle does not match the
design (LP: #838708)
- [dash] Huge performance hit when scrolling search results with
accessibility enabled (LP: #862956)
- DBUS_STARTER_ADDRESS and DBUS_STARTER_BUS_TYPE aren't always unset from
environment making gedit and possibly others fail to start (LP: #873027)
- Win Key can not be disabled in Unity-2d (LP: #873580)
- [dash] Unity-2d dash very slow to open (LP: #881756)
- [tests] LauncherViewTest hanging (LP: #894380)
- [tests] Unit tests failing due to lack of Xserver (LP: #894381)
- [launcher] Alt+F1 broken: does not give the focus to the launcher's
content (LP: #901505)
- [tests] Add Automated User Experience testing (LP: #903495)
- [workspace switcher] Performance can be poor when using the opengl
backend because of window texture sizes that are not limited
(LP: #808716)
- [dash] no way to unmaximize (LP: #860400)
- [launcher] In non-composite mode, background is black (LP: #879288)
- [dash] Unity 2D shows 'Search' instead of 'Run Command' on ALT + F2
(LP: #883392)
- [launcher] Removing icon from launcher makes it hide immediately
(LP: #884410)
- OpenGL disabled regardless of use-opengl setting (LP: #887957)
- if libdir does not equal lib (LP: #888164)
- [launcher] Launcher stuck open while mouse moved to left corner of panel
(LP: #892004)
- [dash] Long results label are truncated instead of elided and a few
pixels of the next line is visible (LP: #901491)
- [launcher] Dash icon missing...