Application: muon-updater (1.2.95 "Daring Dalek")
KDE Platform Version: 4.8.00 (4.8.0
Qt Version: 4.8.0
Operating System: Linux 3.2.0-12-generic x86_64
Distribution: Ubuntu precise (development branch)

-- Information about the crash:
I got a notification that there are available updates, clicked it and tried to update, then muon updater crashed, I saw another notification from apper about updates, opened it then closed it, after a while I used muon updater to install updates, I think it tried (in the first time) to access the backend which was being used by PackageKit, and crashed when it didn't get the lock from it.

The crash can be reproduced some of the time.

-- Backtrace:
Application: Muon Update Manager (muon-updater), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7ffcf5ec97a0 (LWP 17263))]

Thread 3 (Thread 0x7ffce1044700 (LWP 17264)):
#0  0x00007ffcee208141 in g_main_context_prepare () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#1  0x00007ffcee208a5b in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007ffcee208c64 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007ffcf42669a6 in QEventDispatcherGlib::processEvents (this=0x7ffcdc0008b0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#4  0x00007ffcf4236202 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007ffcf4236457 in QEventLoop::exec (this=0x7ffce1043db0, flags=...) at kernel/qeventloop.cpp:204
#6  0x00007ffcf4135f17 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#7  0x00007ffcf4215f9f in QInotifyFileSystemWatcherEngine::run (this=0x133b210) at io/qfilesystemwatcher_inotify.cpp:248
#8  0x00007ffcf4138f3b in QThreadPrivate::start (arg=0x133b210) at thread/qthread_unix.cpp:298
#9  0x00007ffceeacbe2b in start_thread (arg=0x7ffce1044700) at pthread_create.c:304
#10 0x00007ffcf2e310dd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#11 0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7ffcdafbc700 (LWP 17269)):
#0  0x00007ffcf2e25893 in __GI___poll (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007ffcee208b36 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007ffcee208c64 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007ffcf42669a6 in QEventDispatcherGlib::processEvents (this=0x1507c10, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#4  0x00007ffcf4236202 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007ffcf4236457 in QEventLoop::exec (this=0x7ffcdafbbdb0, flags=...) at kernel/qeventloop.cpp:204
#6  0x00007ffcf4135f17 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#7  0x00007ffcf4215f9f in QInotifyFileSystemWatcherEngine::run (this=0x1632d00) at io/qfilesystemwatcher_inotify.cpp:248
#8  0x00007ffcf4138f3b in QThreadPrivate::start (arg=0x1632d00) at thread/qthread_unix.cpp:298
#9  0x00007ffceeacbe2b in start_thread (arg=0x7ffcdafbc700) at pthread_create.c:304
#10 0x00007ffcf2e310dd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#11 0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7ffcf5ec97a0 (LWP 17263)):
[KCrash Handler]
#6  QApt::Package::sourcePackage (this=0x0) at /build/buildd/qapt-1.2.95/src/package.cpp:253
#7  0x00000000004134ad in ChangelogWidget::changelogFetched (this=0x1373ef0, job=0x2480330) at /build/buildd/muon-1.2.95/updater/ChangelogWidget.cpp:173
#8  0x00007ffcf424b801 in QMetaObject::activate (sender=0x2480330, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fff78884df0) at kernel/qobject.cpp:3547
#9  0x00007ffcf46c16a2 in KJob::result (this=<optimized out>, _t1=0x2480330) at ./kjob.moc:208
#10 0x00007ffcf46c16e0 in KJob::emitResult (this=0x2480330) at ../../kdecore/jobs/kjob.cpp:318
#11 0x00007ffcf56f738a in KIO::FileCopyJob::slotResult (this=0x2480330, job=0x24b43b0) at ../../kio/kio/job.cpp:2449
#12 0x00007ffcf424b801 in QMetaObject::activate (sender=0x24b43b0, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fff78884fa0) at kernel/qobject.cpp:3547
#13 0x00007ffcf46c16a2 in KJob::result (this=<optimized out>, _t1=0x24b43b0) at ./kjob.moc:208
#14 0x00007ffcf46c16e0 in KJob::emitResult (this=0x24b43b0) at ../../kdecore/jobs/kjob.cpp:318
#15 0x00007ffcf56efb74 in KIO::SimpleJob::slotFinished (this=0x24b43b0) at ../../kio/kio/job.cpp:494
#16 0x00007ffcf56f75dd in KIO::TransferJob::slotFinished (this=0x24b43b0) at ../../kio/kio/job.cpp:1081
#17 0x00007ffcf424b801 in QMetaObject::activate (sender=0x24800d0, m=<optimized out>, local_signal_index=<optimized out>, argv=0x0) at kernel/qobject.cpp:3547
#18 0x00007ffcf579d971 in KIO::SlaveInterface::dispatch (this=<optimized out>, _cmd=104, rawdata=...) at ../../kio/kio/slaveinterface.cpp:172
#19 0x00007ffcf579a725 in KIO::SlaveInterface::dispatch (this=<optimized out>) at ../../kio/kio/slaveinterface.cpp:88
#20 0x00007ffcf578d9ae in KIO::Slave::gotInput (this=0x24800d0) at ../../kio/kio/slave.cpp:344
#21 0x00007ffcf424b801 in QMetaObject::activate (sender=0x24accf0, m=<optimized out>, local_signal_index=<optimized out>, argv=0x0) at kernel/qobject.cpp:3547
#22 0x00007ffcf56c0867 in dequeue (this=<optimized out>) at ../../kio/kio/connection.cpp:82
#23 KIO::ConnectionPrivate::dequeue (this=0x2480990) at ../../kio/kio/connection.cpp:71
#24 0x00007ffcf42509c6 in QObject::event (this=0x24accf0, e=<optimized out>) at kernel/qobject.cpp:1195
#25 0x00007ffcf35ba5e4 in notify_helper (e=0x2508af0, receiver=0x24accf0, this=0x118d030) at kernel/qapplication.cpp:4555
#26 QApplicationPrivate::notify_helper (this=0x118d030, receiver=0x24accf0, e=0x2508af0) at kernel/qapplication.cpp:4527
#27 0x00007ffcf35bf463 in QApplication::notify (this=0x7fff788861f0, receiver=0x24accf0, e=0x2508af0) at kernel/qapplication.cpp:4416
#28 0x00007ffcf4c96a46 in KApplication::notify (this=0x7fff788861f0, receiver=0x24accf0, event=0x2508af0) at ../../kdeui/kernel/kapplication.cpp:311
#29 0x00007ffcf423741c in QCoreApplication::notifyInternal (this=0x7fff788861f0, receiver=0x24accf0, event=0x2508af0) at kernel/qcoreapplication.cpp:876
#30 0x00007ffcf423b1ea in sendEvent (event=0x2508af0, receiver=0x24accf0) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#31 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x115c790) at kernel/qcoreapplication.cpp:1500
#32 0x00007ffcf4266513 in sendPostedEvents () at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:236
#33 postEventSourceDispatch (s=<optimized out>) at kernel/qeventdispatcher_glib.cpp:279
#34 0x00007ffcee2087da in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#35 0x00007ffcee208ba0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#36 0x00007ffcee208c64 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#37 0x00007ffcf426693f in QEventDispatcherGlib::processEvents (this=0x115e070, flags=...) at kernel/qeventdispatcher_glib.cpp:424
#38 0x00007ffcf36621ce in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#39 0x00007ffcf4236202 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#40 0x00007ffcf4236457 in QEventLoop::exec (this=0x7fff78886180, flags=...) at kernel/qeventloop.cpp:204
#41 0x00007ffcf423b4e7 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1148
#42 0x000000000040f417 in main (argc=1, argv=0x7fff78886468) at /build/buildd/muon-1.2.95/updater/main.cpp:61

Possible duplicates by query: bug 291452, bug 290230, bug 289984.

Reported using DrKonqi