I rebuilt print-manager with debugging symbols, below goes a new backtrace. It crashes everytime plasma-desktop starts.

Application: Powłoka pulpitu Plazmy (plasma-desktop), signal: Segmentation fault
Using host libthread_db library "/lib/i386-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0xb1234740 (LWP 29647))]

Thread 5 (Thread 0xad745b40 (LWP 29652)):
#0  0xb76e7424 in __kernel_vsyscall ()
#1  0xb209e84b in pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/i386/i686/../i486/pthread_cond_wait.S:187
#2  0xb759b9bc in __pthread_cond_wait (cond=0xb31a08d0, mutex=0xb31a08b8) at forward.c:149
#3  0xb309def2 in ?? () from /usr/lib/i386-linux-gnu/libQtScript.so.4
#4  0xb309df3f in ?? () from /usr/lib/i386-linux-gnu/libQtScript.so.4
#5  0xb209ad78 in start_thread (arg=0xad745b40) at pthread_create.c:311
#6  0xb758e01e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:131

Thread 4 (Thread 0xa6a5db40 (LWP 29655)):
#0  0xb75ca173 in __x86.get_pc_thunk.bx () from /lib/i386-linux-gnu/libc.so.6
#1  0xb759bbd8 in pthread_mutex_unlock (mutex=0xa6100558) at forward.c:194
#2  0xb1fc8be0 in g_mutex_unlock (mutex=mutex@entry=0xa61004e0) at /build/buildd/glib2.0-2.38.0/./glib/gthread-posix.c:232
#3  0xb1f85572 in g_main_context_check (context=context@entry=0xa61004e0, max_priority=2147483647, fds=fds@entry=0xa6102288, n_fds=n_fds@entry=1) at /build/buildd/glib2.0-2.38.0/./glib/gmain.c:3554
#4  0xb1f85aea in g_main_context_iterate (context=context@entry=0xa61004e0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.38.0/./glib/gmain.c:3709
#5  0xb1f85c98 in g_main_context_iteration (context=0xa61004e0, may_block=1) at /build/buildd/glib2.0-2.38.0/./glib/gmain.c:3773
#6  0xb5ff78df in QEventDispatcherGlib::processEvents (this=0xa6100468, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#7  0xb5fc69f3 in QEventLoop::processEvents (this=this@entry=0xa6a5d228, flags=...) at kernel/qeventloop.cpp:149
#8  0xb5fc6d19 in QEventLoop::exec (this=this@entry=0xa6a5d228, flags=...) at kernel/qeventloop.cpp:204
#9  0xb5eb5e3d in QThread::exec (this=this@entry=0x91732f0) at thread/qthread.cpp:542
#10 0xb5fa6e14 in QInotifyFileSystemWatcherEngine::run (this=0x91732f0) at io/qfilesystemwatcher_inotify.cpp:265
#11 0xb5eb872f in QThreadPrivate::start (arg=0x91732f0) at thread/qthread_unix.cpp:338
#12 0xb209ad78 in start_thread (arg=0xa6a5db40) at pthread_create.c:311
#13 0xb758e01e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:131

Thread 3 (Thread 0xa52ffb40 (LWP 29657)):
#0  g_mutex_get_impl (mutex=0xa5308d90) at /build/buildd/glib2.0-2.38.0/./glib/gthread-posix.c:123
#1  0xb1fc8b98 in g_mutex_lock (mutex=mutex@entry=0xa5308d90) at /build/buildd/glib2.0-2.38.0/./glib/gthread-posix.c:213
#2  0xb1f85b34 in g_main_context_poll (priority=2147483647, n_fds=1, fds=0xa49023a0, timeout=-1, context=0xa5308d90) at /build/buildd/glib2.0-2.38.0/./glib/gmain.c:4001
#3  g_main_context_iterate (context=0xa5308d90, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.38.0/./glib/gmain.c:3707
#4  0xb1f8603b in g_main_loop_run (loop=0xa5308d58) at /build/buildd/glib2.0-2.38.0/./glib/gmain.c:3906
#5  0xa5df20ea in gdbus_shared_thread_func (user_data=0xa5308d78) at /build/buildd/glib2.0-2.38.0/./gio/gdbusprivate.c:278
#6  0xb1fabc3a in g_thread_proxy (data=0x92247b0) at /build/buildd/glib2.0-2.38.0/./glib/gthread.c:798
#7  0xb209ad78 in start_thread (arg=0xa52ffb40) at pthread_create.c:311
#8  0xb758e01e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:131

Thread 2 (Thread 0xa10f5b40 (LWP 29660)):
#0  0xb76e7424 in __kernel_vsyscall ()
#1  0xb75a14d2 in clock_gettime (clock_id=1, tp=0xa10f5038) at ../sysdeps/unix/clock_gettime.c:115
#2  0xb5f133ec in do_gettime (frac=0xa10f5030, sec=0xa10f5028) at tools/qelapsedtimer_unix.cpp:123
#3  qt_gettime () at tools/qelapsedtimer_unix.cpp:140
#4  0xb5ff8c61 in QTimerInfoList::updateCurrentTime (this=this@entry=0xa530a35c) at kernel/qeventdispatcher_unix.cpp:354
#5  0xb5ff7b5e in timerSourceCheckHelper (src=0xa530a328) at kernel/qeventdispatcher_glib.cpp:150
#6  0xb1f8557f in g_main_context_check (context=context@entry=0xa530a160, max_priority=2147483647, fds=fds@entry=0xa530a3f0, n_fds=n_fds@entry=1) at /build/buildd/glib2.0-2.38.0/./glib/gmain.c:3556
#7  0xb1f85aea in g_main_context_iterate (context=context@entry=0xa530a160, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.38.0/./glib/gmain.c:3709
#8  0xb1f85c98 in g_main_context_iteration (context=0xa530a160, may_block=1) at /build/buildd/glib2.0-2.38.0/./glib/gmain.c:3773
#9  0xb5ff78df in QEventDispatcherGlib::processEvents (this=0xa530a318, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#10 0xb5fc69f3 in QEventLoop::processEvents (this=this@entry=0xa10f5248, flags=...) at kernel/qeventloop.cpp:149
#11 0xb5fc6d19 in QEventLoop::exec (this=this@entry=0xa10f5248, flags=...) at kernel/qeventloop.cpp:204
#12 0xb5eb5e3d in QThread::exec (this=0x9a54d60) at thread/qthread.cpp:542
#13 0xa28911fe in KCupsConnection::run (this=0x9a54d60) at ../../libkcups/KCupsConnection.cpp:303
#14 0xb5eb872f in QThreadPrivate::start (arg=0x9a54d60) at thread/qthread_unix.cpp:338
#15 0xb209ad78 in start_thread (arg=0xa10f5b40) at pthread_create.c:311
#16 0xb758e01e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:131

Thread 1 (Thread 0xb1234740 (LWP 29647)):
[KCrash Handler]
#7  0xa28aa1e9 in JobModel::updateJob (this=0x8ad2448, pos=2, job=...) at ../../libkcups/JobModel.cpp:358
#8  0xa28a9896 in JobModel::getJobFinished (this=0x8ad2448) at ../../libkcups/JobModel.cpp:232
#9  0xa28abef1 in JobModel::qt_static_metacall (_o=0x8ad2448, _c=QMetaObject::InvokeMetaMethod, _id=1, _a=0xa5353bc8) at ./JobModel.moc:113
#10 0xb5fd977a in QMetaCallEvent::placeMetaCall (this=0xa533c138, object=0x8ad2448) at kernel/qobject.cpp:524
#11 0xb5fe158b in QObject::event (this=0x8ad2448, e=0xa533c138) at kernel/qobject.cpp:1194
#12 0xb54d8744 in QApplicationPrivate::notify_helper (this=0x8906a68, receiver=0x8ad2448, e=0xa533c138) at kernel/qapplication.cpp:4567
#13 0xb54df223 in QApplication::notify (this=0x88a73b0, receiver=receiver@entry=0x8ad2448, e=e@entry=0xa533c138) at kernel/qapplication.cpp:4353
#14 0xb663c024 in KApplication::notify (this=0x88a73b0, receiver=0x8ad2448, event=0xa533c138) at ../../kdeui/kernel/kapplication.cpp:311
#15 0xb5fc7eda in QCoreApplication::notifyInternal (this=0x88a73b0, receiver=receiver@entry=0x8ad2448, event=event@entry=0xa533c138) at kernel/qcoreapplication.cpp:946
#16 0xb5fcb6ad in sendEvent (event=0xa533c138, receiver=0x8ad2448) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#17 QCoreApplicationPrivate::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0, data=0x8872130) at kernel/qcoreapplication.cpp:1570
#18 0xb5fcbbbc in QCoreApplication::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0) at kernel/qcoreapplication.cpp:1463
#19 0xb5ff7f6e in sendPostedEvents () at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:236
#20 postEventSourceDispatch (s=s@entry=0x8906d98) at kernel/qeventdispatcher_glib.cpp:279
#21 0xb1f8582e in g_main_dispatch (context=0x8906d20, context@entry=0x88786c8) at /build/buildd/glib2.0-2.38.0/./glib/gmain.c:3065
#22 g_main_context_dispatch (context=context@entry=0x8906d20) at /build/buildd/glib2.0-2.38.0/./glib/gmain.c:3641
#23 0xb1f85bd8 in g_main_context_iterate (context=context@entry=0x8906d20, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.38.0/./glib/gmain.c:3712
#24 0xb1f85c98 in g_main_context_iteration (context=0x8906d20, may_block=1) at /build/buildd/glib2.0-2.38.0/./glib/gmain.c:3773
#25 0xb5ff78bf in QEventDispatcherGlib::processEvents (this=this@entry=0x8872ea8, flags=...) at kernel/qeventdispatcher_glib.cpp:424
#26 0xb558d32e in QGuiEventDispatcherGlib::processEvents (this=0x8872ea8, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#27 0xb5fc69f3 in QEventLoop::processEvents (this=this@entry=0xbfd3b328, flags=...) at kernel/qeventloop.cpp:149
#28 0xb5fc6d19 in QEventLoop::exec (this=this@entry=0xbfd3b328, flags=...) at kernel/qeventloop.cpp:204
#29 0xb5fcc89e in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1218
#30 0xb54d6974 in QApplication::exec () at kernel/qapplication.cpp:3828
#31 0xb76a5947 in kdemain (argc=1, argv=0xbfd3b4c4) at ../../../../plasma/desktop/shell/main.cpp:126
#32 0x0804858b in main (argc=1, argv=0xbfd3b4c4) at plasma-desktop_dummy.cpp:3