Application: muon-installer (1.4.1)
KDE Platform Version: 4.10.00
Qt Version: 4.8.3
Operating System: Linux 3.5.0-23-generic x86_64
Distribution: Netrunner 12.12

-- Information about the crash:
- What I was doing when the application crashed: I was using Firefox for linux 18 and Steam, to open the Muon exhibited the same error message and then opened without problems. To be closed and reopened again the error message appears. During this message, Muon is frozen a few seconds.

- Unusual behavior I noticed: Muon freeze for a few seconds before your operation

- Custom settings of the application: Not

The crash can be reproduced some of the time.

-- Backtrace:
Application: Muon Software Center (muon-installer), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f4a3d0e5780 (LWP 6923))]

Thread 2 (Thread 0x7f4a265e8700 (LWP 6929)):
#0  0x00007f4a39d90303 in __GI___poll (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007f4a34fccd84 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f4a34fccea4 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f4a3bcc0c16 in QEventDispatcherGlib::processEvents (this=0x7f4a1c0008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#4  0x00007f4a3bc912bf in QEventLoop::processEvents (this=this@entry=0x7f4a265e7dd0, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007f4a3bc91548 in QEventLoop::exec (this=0x7f4a265e7dd0, flags=...) at kernel/qeventloop.cpp:204
#6  0x00007f4a3bb92b10 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#7  0x00007f4a3bc719af in QInotifyFileSystemWatcherEngine::run (this=0x2103e00) at io/qfilesystemwatcher_inotify.cpp:248
#8  0x00007f4a3bb95aec in QThreadPrivate::start (arg=0x2103e00) at thread/qthread_unix.cpp:338
#9  0x00007f4a39a92e9a in start_thread (arg=0x7f4a265e8700) at pthread_create.c:308
#10 0x00007f4a39d9bcbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#11 0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f4a3d0e5780 (LWP 6923)):
[KCrash Handler]
#6  0x00007f4a3c5addc2 in pkgDepCache::InstCount() () from /usr/lib/libqapt.so.1
#7  0x00007f4a3c5a633c in QApt::Backend::toInstallCount() const () from /usr/lib/libqapt.so.1
#8  0x00007f4a3c5a739b in QApt::Backend::areChangesMarked() const () from /usr/lib/libqapt.so.1
#9  0x00007f4a3ccca1d1 in MuonMainWindow::queryExit() () from /usr/lib/libmuonprivate.so.1
#10 0x00007f4a3b7b341c in KMainWindow::closeEvent (this=0x2271240, e=0x7fffad2a4ea0) at ../../kdeui/widgets/kmainwindow.cpp:604
#11 0x00007f4a3a585c02 in QWidget::event (this=0x2271240, event=0x7fffad2a4ea0) at kernel/qwidget.cpp:8529
#12 0x00007f4a3a94e1cb in QMainWindow::event (this=0x2271240, event=0x7fffad2a4ea0) at widgets/qmainwindow.cpp:1478
#13 0x00007f4a3b7ed3a8 in KXmlGuiWindow::event (this=0x2271240, ev=0x7fffad2a4ea0) at ../../kdeui/xmlgui/kxmlguiwindow.cpp:126
#14 0x00007f4a3a535e9c in QApplicationPrivate::notify_helper (this=this@entry=0x20bc930, receiver=receiver@entry=0x2271240, e=e@entry=0x7fffad2a4ea0) at kernel/qapplication.cpp:4562
#15 0x00007f4a3a53a30a in QApplication::notify (this=0x7fffad2a8040, receiver=0x2271240, e=0x7fffad2a4ea0) at kernel/qapplication.cpp:4423
#16 0x00007f4a3b6fb636 in KApplication::notify (this=0x7fffad2a8040, receiver=0x2271240, event=0x7fffad2a4ea0) at ../../kdeui/kernel/kapplication.cpp:311
#17 0x00007f4a3bc9256e in QCoreApplication::notifyInternal (this=0x7fffad2a8040, receiver=0x2271240, event=0x7fffad2a4ea0) at kernel/qcoreapplication.cpp:915
#18 0x00007f4a3a57f6b1 in sendEvent (event=<optimized out>, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#19 QWidgetPrivate::close_helper (this=0x2271bd0, mode=QWidgetPrivate::CloseWithSpontaneousEvent) at kernel/qwidget.cpp:7937
#20 0x00007f4a3a5b500f in QApplication::x11ClientMessage (this=<optimized out>, w=0x2271240, event=<optimized out>, passive_only=<optimized out>) at kernel/qapplication_x11.cpp:3192
#21 0x00007f4a3a5b346c in QApplication::x11ProcessEvent (this=0x7fffad2a8040, event=0x7fffad2a5470) at kernel/qapplication_x11.cpp:3876
#22 0x00007f4a3a5dafa2 in x11EventSourceDispatch (s=0x20b5fb0, callback=0x0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#23 0x00007f4a34fccab5 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#24 0x00007f4a34fccde8 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#25 0x00007f4a34fccea4 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#26 0x00007f4a3bcc0bf6 in QEventDispatcherGlib::processEvents (this=0x208a120, flags=...) at kernel/qeventdispatcher_glib.cpp:424
#27 0x00007f4a3a5dac1e in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#28 0x00007f4a3bc9689f in QCoreApplication::processEvents (flags=...) at kernel/qcoreapplication.cpp:1102
#29 0x00007f4a3c5b8123 in QApt::CacheBuildProgress::Update() () from /usr/lib/libqapt.so.1
#30 0x00007f4a36e55572 in pkgCacheGenerator::MergeList(pkgCacheGenerator::ListParser&, pkgCache::VerIterator*) () from /usr/lib/x86_64-linux-gnu/libapt-pkg.so.4.12
#31 0x00007f4a36ea974a in debPackagesIndex::Merge(pkgCacheGenerator&, OpProgress*) const () from /usr/lib/x86_64-linux-gnu/libapt-pkg.so.4.12
#32 0x00007f4a36e4e642 in ?? () from /usr/lib/x86_64-linux-gnu/libapt-pkg.so.4.12
#33 0x00007f4a36e51419 in pkgCacheGenerator::MakeStatusCache(pkgSourceList&, OpProgress*, MMap**, bool) () from /usr/lib/x86_64-linux-gnu/libapt-pkg.so.4.12
#34 0x00007f4a36e480d1 in pkgCacheFile::BuildCaches(OpProgress*, bool) () from /usr/lib/x86_64-linux-gnu/libapt-pkg.so.4.12
#35 0x00007f4a36e4846c in pkgCacheFile::Open(OpProgress*, bool) () from /usr/lib/x86_64-linux-gnu/libapt-pkg.so.4.12
#36 0x00007f4a3c5b7e65 in QApt::Cache::open() () from /usr/lib/libqapt.so.1
#37 0x00007f4a3c5a4b98 in QApt::Backend::reloadCache() () from /usr/lib/libqapt.so.1
#38 0x00007f4a3ccbddc2 in ApplicationBackend::reload() () from /usr/lib/libmuonprivate.so.1
#39 0x000000000041ed66 in ApplicationWindow::sourcesEditorFinished(int) ()
#40 0x000000000041fd5a in ApplicationWindow::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) ()
#41 0x00007f4a3bca7f5f in QMetaObject::activate (sender=0x2612640, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fffad2a7530) at kernel/qobject.cpp:3547
#42 0x00007f4a3bc280ff in QProcess::finished (this=this@entry=0x2612640, _t1=1, _t2=QProcess::NormalExit) at .moc/release-shared/moc_qprocess.cpp:156
#43 0x00007f4a3bc2c1f7 in QProcessPrivate::_q_processDied (this=0x3458680) at io/qprocess.cpp:1068
#44 0x00007f4a3bc2c27e in qt_static_metacall (_a=<optimized out>, _id=<optimized out>, _o=<optimized out>, _c=<optimized out>) at .moc/release-shared/moc_qprocess.cpp:92
#45 QProcess::qt_static_metacall (_o=<optimized out>, _c=<optimized out>, _id=<optimized out>, _a=<optimized out>) at .moc/release-shared/moc_qprocess.cpp:69
#46 0x00007f4a3bca7f5f in QMetaObject::activate (sender=0x2894990, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fffad2a76e0) at kernel/qobject.cpp:3547
#47 0x00007f4a3bcf279e in QSocketNotifier::activated (this=<optimized out>, _t1=105) at .moc/release-shared/moc_qsocketnotifier.cpp:103
#48 0x00007f4a3bcaf7eb in QSocketNotifier::event (this=0x2894990, e=0x7fffad2a7d00) at kernel/qsocketnotifier.cpp:317
#49 0x00007f4a3a535e9c in QApplicationPrivate::notify_helper (this=this@entry=0x20bc930, receiver=receiver@entry=0x2894990, e=e@entry=0x7fffad2a7d00) at kernel/qapplication.cpp:4562
#50 0x00007f4a3a53a30a in QApplication::notify (this=0x7fffad2a8040, receiver=0x2894990, e=0x7fffad2a7d00) at kernel/qapplication.cpp:4423
#51 0x00007f4a3b6fb636 in KApplication::notify (this=0x7fffad2a8040, receiver=0x2894990, event=0x7fffad2a7d00) at ../../kdeui/kernel/kapplication.cpp:311
#52 0x00007f4a3bc9256e in QCoreApplication::notifyInternal (this=0x7fffad2a8040, receiver=0x2894990, event=0x7fffad2a7d00) at kernel/qcoreapplication.cpp:915
#53 0x00007f4a3bcc03f8 in sendEvent (event=0x7fffad2a7d00, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#54 socketNotifierSourceDispatch (source=0x20b9420) at kernel/qeventdispatcher_glib.cpp:110
#55 0x00007f4a34fccab5 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#56 0x00007f4a34fccde8 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#57 0x00007f4a34fccea4 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#58 0x00007f4a3bcc0c16 in QEventDispatcherGlib::processEvents (this=0x208a120, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#59 0x00007f4a3a5dac1e in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#60 0x00007f4a3bc912bf in QEventLoop::processEvents (this=this@entry=0x7fffad2a7f40, flags=...) at kernel/qeventloop.cpp:149
#61 0x00007f4a3bc91548 in QEventLoop::exec (this=0x7fffad2a7f40, flags=...) at kernel/qeventloop.cpp:204
#62 0x00007f4a3bc96708 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1187
#63 0x000000000041b63b in main ()

Reported using DrKonqi