unity-2d-places crashed with SIGSEGV in disconnect()

Binary package hint: unity-2d

This is bug 791213, with a better stack trace (for all threads), and possibly useful console messages. I produced this by installing all the debug packages providing symbols referenced in Didier Roche's manual trace (https://bugs.launchpad.net/ubuntu/+source/unity-2d/+bug/791213/comments/2), after Cristian Aravena Romero's pointed out how that trace was incomplete (https://bugs.launchpad.net/ubuntu/+source/unity-2d/+bug/791213/comments/5).

The trace here is the best I was able to produce (using binary packages), and is more complete than Didier Roche's manual trace, but this trace is still not perfect. I think some information may be destroyed by stack corruption every time this crash occurs. Most notably, the line

        #44 0x01c6b2d9 in ?? ()

appears in Didier Roche's manual trace, and the corresponding line

        #44 0x063f92d9 in ?? ()

appears in the trace here.

To produce this, I ran unity-2d-places manually by opening a Terminal window and running the command "unity-2d-places" (without the quotes). The following messages were printed immediately:

unity-2d-places: [DEBUG] static void WindowImageProvider::activateComposite(): Server supports the Composite extension (ver 0.4)
unity-2d-places: [DEBUG] virtual void Hotkey::connectNotify(const char*): Grabbing hotkey "Meta+A"
unity-2d-places: [WARNING] int _x_grabkey_errhandler(Display*, XErrorEvent*): Call to XGrabKey failed, this usually means some other client already reserved the hotkey.
unity-2d-places: [DEBUG] virtual void Hotkey::connectNotify(const char*): Grabbing hotkey "Meta+F"
unity-2d-places: [WARNING] int _x_grabkey_errhandler(Display*, XErrorEvent*): Call to XGrabKey failed, this usually means some other client already reserved the hotkey.
unity-2d-places: [WARNING] QWidget::setMinimumSize: (/LauncherContextualMenu) Negative sizes (57,-1) are not possible
unity-2d-places: [WARNING] QWidget::setMinimumSize: (/LauncherContextualMenu) Negative sizes (57,-1) are not possible
unity-2d-places: [WARNING] QWidget::setMinimumSize: (/LauncherContextualMenu) Negative sizes (57,-1) are not possible

I waited a couple of minutes to make sure that everything was completely loaded, then clicked on the home button, and the following messages were printed, culminating in the crash:

unity-2d-places: [WARNING] file:///usr/share/unity-2d/places/HomeShortcutsCustomized.qml: File not found
unity-2d-places: [WARNING] key not set
unity-2d-places: [WARNING] libindicator: Shortcut Group does not have key 'TargetEnvironment' falling back to deprecated use of 'OnlyShowIn' and 'NotShowIn'.
unity-2d-places: [WARNING] file:///usr/share/unity-2d/places/HomeShortcuts.qml:22:1: QML Flow: Possible anchor loop detected on fill.
unity-2d-places: [WARNING] file:///usr/share/unity-2d/places/HomeShortcuts.qml:22:1: QML Flow: Possible anchor loop detected on fill.
unity-2d-places: [WARNING] file:///usr/share/unity-2d/places/HomeShortcuts.qml:22:1: QML Flow: Possible anchor loop detected on fill.
unity-2d-places: [WARNING] file:///usr/share/unity-2d/places/HomeShortcuts.qml:22:1: QML Flow: Possible anchor loop detected on fill.
unity-2d-places: [WARNING] file:///usr/share/unity-2d/places/HomeShortcuts.qml:22:1: QML Flow: Possible anchor loop detected on fill.
unity-2d-places: [WARNING] file:///usr/share/unity-2d/places/HomeShortcuts.qml:22:1: QML Flow: Possible anchor loop detected on fill.
unity-2d-places: [WARNING] file:///usr/share/unity-2d/places/HomeShortcuts.qml:22:1: QML Flow: Possible anchor loop detected on fill.
unity-2d-places: [WARNING] file:///usr/share/unity-2d/places/HomeShortcuts.qml:22:1: QML Flow: Possible anchor loop detected on fill.
unity-2d-places: [WARNING] file:///usr/share/unity-2d/places/Home.qml:79:9: QML Text: Binding loop detected for property "width"
Segmentation fault (core dumped)

I plan to mark this as a duplicate of bug 791213 shortly, and to post a comment in that bug linking to it.

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: unity-2d-places 3.8.6-0ubuntu2
ProcVersionSignature: Ubuntu 2.6.39-3.10-generic 2.6.39
Uname: Linux 2.6.39-3-generic i686
Architecture: i386
Date: Sun Jun 5 03:12:45 2011
ExecutablePath: /usr/bin/unity-2d-places
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Alpha i386 (20110604)
ProcCmdline: unity-2d-places
ProcEnviron:
 SHELL=/bin/bash
 LANG=en_US.UTF-8
 LANGUAGE=en_US:en
SegvAnalysis:
 Segfault happened at: 0x2f3191 <QDeclarativeCompiledBindingsPrivate::run(int, QDeclarativeContextData*, QDeclarativeDelayedError*, QObject*, QObject*, QDeclarativePropertyPrivate::WriteFlags)+4177>: mov %eax,(%ecx)
 PC (0x002f3191) ok
 source "%eax" ok
 destination "(%ecx)" (0x00000006) not located in a known VMA region (needed writable region)!
SegvReason: writing NULL VMA
Signal: 11
SourcePackage: unity-2d
StacktraceTop:
 disconnect (this=0x8b95d00, instrIndex=146378636, context=0x8b95b90, error=0x8b99194, scope=0x8b9a3f0, output=0x8b9a3f0, storeFlags=...) at ../../include/QtDeclarative/private/../../../src/declarative/qml/qdeclarativenotifier_p.h:206
 unsubscribe (this=0x8b95d00, instrIndex=146378636, context=0x8b95b90, error=0x8b99194, scope=0x8b9a3f0, output=0x8b9a3f0, storeFlags=...) at qml/qdeclarativecompiledbindings.cpp:664
 subscribeId (this=0x8b95d00, instrIndex=146378636, context=0x8b95b90, error=0x8b99194, scope=0x8b9a3f0, output=0x8b9a3f0, storeFlags=...) at qml/qdeclarativecompiledbindings.cpp:671
 QDeclarativeCompiledBindingsPrivate::run (this=0x8b95d00, instrIndex=146378636, context=0x8b95b90, error=0x8b99194, scope=0x8b9a3f0, output=0x8b9a3f0, storeFlags=...) at qml/qdeclarativecompiledbindings.cpp:1150
 QDeclarativeCompiledBindingsPrivate::run (this=0x8b95d00, binding=0x8b99174, flags=...) at qml/qdeclarativecompiledbindings.cpp:375
Title: unity-2d-places crashed with SIGSEGV in disconnect()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare