Can you reproduce the situation that caused the freeze? 
Thanks

hi!

This bug just occured once again but i still couldn't find out how to trigger it.

I installed some more debug packages, here's the updated backtrace from 4.3rc2:

Application: Kontact (kontact), signal: Segmentation fault
[Current thread is 0 (LWP 4386)]

Thread 2 (Thread 0xac4eab90 (LWP 29963)):
#0  0xb7ef8430 in __kernel_vsyscall ()
#1  0xb505c0e5 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0
#2  0xb587c2ed in __pthread_cond_wait (cond=0x992c170, mutex=0x992c158) at forward.c:139
#3  0xb5a5f5b2 in QWaitCondition::wait (this=0x992bff0, mutex=0x99ed5b8, time=4294967295) at thread/qwaitcondition_unix.cpp:87
#4  0xb0a98148 in ThreadWeaver::WeaverImpl::blockThreadUntilJobsAreBeingAssigned (this=0x992bfd8, th=0xa6642e0) at /build/buildd/kde4libs-4.2.96/threadweaver/Weaver/WeaverImpl.cpp:365
#5  0xb0a9aeec in ThreadWeaver::WorkingHardState::waitForAvailableJob (this=0x99ed338, th=0xa6642e0) at /build/buildd/kde4libs-4.2.96/threadweaver/Weaver/WorkingHardState.cpp:80
#6  0xb0a96d2b in ThreadWeaver::WeaverImpl::waitForAvailableJob (this=0x992bfd8, th=0xa6642e0) at /build/buildd/kde4libs-4.2.96/threadweaver/Weaver/WeaverImpl.cpp:356
#7  0xb0a9afea in ThreadWeaver::WorkingHardState::applyForWork (this=0x99ed338, th=0xa6642e0) at /build/buildd/kde4libs-4.2.96/threadweaver/Weaver/WorkingHardState.cpp:71
#8  0xb0a986d3 in ThreadWeaver::WeaverImpl::applyForWork (this=0x992bfd8, th=0xa6642e0, previous=0xafa7618) at /build/buildd/kde4libs-4.2.96/threadweaver/Weaver/WeaverImpl.cpp:351
#9  0xb0a98fbe in ThreadWeaver::ThreadRunHelper::run (this=0xac4ea330, parent=0x992bfd8, th=0xa6642e0) at /build/buildd/kde4libs-4.2.96/threadweaver/Weaver/Thread.cpp:87
#10 0xb0a995fb in ThreadWeaver::Thread::run (this=0xa6642e0) at /build/buildd/kde4libs-4.2.96/threadweaver/Weaver/Thread.cpp:142
#11 0xb5a5e56e in QThreadPrivate::start (arg=0xa6642e0) at thread/qthread_unix.cpp:189
#12 0xb50584ff in start_thread (arg=0xac4eab90) at pthread_create.c:297
#13 0xb586d49e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130

Thread 1 (Thread 0xb4770b30 (LWP 4386)):
[KCrash Handler]
#12 0xb7ef8430 in __kernel_vsyscall ()
#13 0xb58657b1 in select () from /lib/tls/i686/cmov/libc.so.6
#14 0xb4b6cca7 in _xcb_conn_wait (c=0x93fc6c0, cond=0xbff149f8, vector=0x0, count=0x0) at /build/buildd/libxcb-1.1.93/./src/xcb_conn.c:283
#15 0xb4b6ea12 in xcb_wait_for_reply (c=0x93fc6c0, request=11619720, e=0xbff14a78) at /build/buildd/libxcb-1.1.93/./src/xcb_in.c:376
#16 0xb55dfcae in _XReply (dpy=0x93f9b48, rep=0xbff14aa0, extra=0, discard=1) at ../../src/xcb_io.c:454
#17 0xb55d4d41 in XTranslateCoordinates (dpy=0x93f9b48, src_win=209, dest_win=23812357, src_x=825, src_y=760, dst_x=0xbff14b28, dst_y=0xbff14b28, child=0xbff14b1c) at ../../src/TrCoords.c:53
#18 0xb6075d08 in QApplication::topLevelAt (p=@0xbff14cd0) at kernel/qapplication_x11.cpp:2954
#19 0xb6014585 in QApplication::widgetAt (p=@0xbff14cd0) at kernel/qapplication.cpp:1089
#20 0xb6019b58 in QApplicationPrivate::sendMouseEvent (receiver=0x95c37b0, event=0xbff14cb8, alienWidget=0x0, nativeWidget=0x95c37b0, buttonDown=0xb68bdaa0, lastMouseReceiver=@0xb68bdaa4)
    at kernel/qapplication.cpp:2947
#21 0xb6089aee in QETWidget::translateMouseEvent (this=0x95c37b0, event=0xbff1634c) at kernel/qapplication_x11.cpp:4448
#22 0xb6088ead in QApplication::x11ProcessEvent (this=0xbff16638, event=0xbff1634c) at kernel/qapplication_x11.cpp:3444
#23 0xb60b406a in x11EventSourceDispatch (s=0x93e4ea8, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#24 0xb4c26b88 in IA__g_main_context_dispatch (context=0x93e4290) at /build/buildd/glib2.0-2.20.1/glib/gmain.c:1814
#25 0xb4c2a0eb in g_main_context_iterate (context=0x93e4290, block=1, dispatch=1, self=0x93e14b8) at /build/buildd/glib2.0-2.20.1/glib/gmain.c:2448
#26 0xb4c2a268 in IA__g_main_context_iteration (context=0x93e4290, may_block=1) at /build/buildd/glib2.0-2.20.1/glib/gmain.c:2511
#27 0xb5b7e1d8 in QEventDispatcherGlib::processEvents (this=0x93bb028, flags={i = -1074699000}) at kernel/qeventdispatcher_glib.cpp:324
#28 0xb60b3765 in QGuiEventDispatcherGlib::processEvents (this=0x93bb028, flags={i = -1074698952}) at kernel/qguieventdispatcher_glib.cpp:202
#29 0xb5b50dda in QEventLoop::processEvents (this=0xbff165b0, flags={i = -1074698888}) at kernel/qeventloop.cpp:149
#30 0xb5b5121a in QEventLoop::exec (this=0xbff165b0, flags={i = -1074698824}) at kernel/qeventloop.cpp:200
#31 0xb5b536c9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#32 0xb6011a47 in QApplication::exec () at kernel/qapplication.cpp:3526
#33 0x0804bfef in main (argc=1, argv=0xbff16934) at /build/buildd/kdepim-4.2.96/kontact/src/main.cpp:218

i still don't know how to reproduce this bug but it occurs once in a while. today i attached to the process with gdb and did a bt full with kde 4.3:


#0  0xb7ff2430 in __kernel_vsyscall ()
No symbol table info available.
#1  0xb59817b1 in select () from /lib/tls/i686/cmov/libc.so.6
No locals.
#2  0xb4c87ca7 in _xcb_conn_wait (c=0x825f8d0, cond=0xbfe0c0f8, vector=0x0, count=0x0)
    at /build/buildd/libxcb-1.1.93/./src/xcb_conn.c:283
	ret = 8
	rfds = {__fds_bits = {256, 0 <repeats 31 times>}}
	wfds = {__fds_bits = {0 <repeats 32 times>}}
#3  0xb4c89a12 in xcb_wait_for_reply (c=0x825f8d0, request=9439611, e=0xbfe0c178)
    at /build/buildd/libxcb-1.1.93/./src/xcb_in.c:376
	cond = {__data = {__lock = 0, __futex = 0, __total_seq = 0, __wakeup_seq = 0, __woken_seq = 0, 
    __mutex = 0x0, __nwaiters = 0, __broadcast_seq = 0}, __size = '\0' <repeats 47 times>, __align = 0}
	reader = {request = 9439611, data = 0xbfe0c0f8, next = 0x0}
	prev_reader = (reader_list **) 0x8260958
	widened_request = <value optimized out>
	ret = (void *) 0x0
#4  0xb56fbcae in _XReply (dpy=0x8248d60, rep=0xbfe0c1a0, extra=0, discard=1) at ../../src/xcb_io.c:454
	error = <value optimized out>
	c = (xcb_connection_t *) 0x825f8d0
	__PRETTY_FUNCTION__ = "_XReply"
#5  0xb56f0d41 in XTranslateCoordinates (dpy=0x8248d60, src_win=208, dest_win=76108219, src_x=828, src_y=756, 
    dst_x=0xbfe0c228, dst_y=0xbfe0c228, child=0xbfe0c21c) at ../../src/TrCoords.c:53
	rep = {type = 0 '\0', sameScreen = 3 '\003', sequenceNumber = 2426, length = 76108219, child = 2621440, 
  dstX = 0, dstY = 0, pad2 = 0, pad3 = 160756728, pad4 = 134863103, pad5 = 3055349425}
#6  0xb6194f08 in QApplication::topLevelAt (p=@0xbfe0c3d0) at kernel/qapplication_x11.cpp:2952
	wid = 71303407
	widget = (class QWidget *) 0x91f26d0
	ctarget = 76108219
	i = 9
	list = {{p = {static shared_null = {ref = {_q_value = 57762}, alloc = 0, begin = 0, end = 0, 
        sharable = 1, array = {0x0}}, d = 0xaa0ecd8}, d = 0xaa0ecd8}}
	screen = 0
	unused = 16
	x = 828
	y = 756
	target = 75497788
	w = <value optimized out>
#7  0xb61336f5 in QApplication::widgetAt (p=@0xbfe0c3d0) at kernel/qapplication.cpp:1090
	window = <value optimized out>
	child = <value optimized out>
#8  0xb6138cb8 in QApplicationPrivate::sendMouseEvent (receiver=0xa7f1d50, event=0xbfe0c3b8, alienWidget=0x0, 
    nativeWidget=0xa7f1d50, buttonDown=0xb69b2aa0, lastMouseReceiver=@0xb69b2aa4) at kernel/qapplication.cpp:2946
	receiverGuard = {o = 0x0}
	nativeGuard = {o = 0x0}
	alienGuard = {o = 0x0}
	activePopupWidget = {o = 0x0}
	graphicsWidget = false
	result = true
#9  0xb61a8cce in QETWidget::translateMouseEvent (this=0xa7f1d50, event=0xbfe0da4c)
    at kernel/qapplication_x11.cpp:4409
	alienWidget = (class QWidget *) 0x0
	widget = <value optimized out>
	oldOpenPopupCount = 0
	e = {<QInputEvent> = {<QEvent> = {_vptr.QEvent = 0xb699a360, d = 0x0, t = 2, posted = 0, spont = 0, 
      m_accept = 1, reserved = 0}, modState = {i = 0}}, p = {xp = 7, yp = 12}, g = {xp = 828, yp = 756}, 
  b = Qt::LeftButton, mouseState = {i = 1}}
	type = QEvent::MouseButtonPress
	pos = {xp = 7, yp = 12}
	globalPos = {xp = 828, yp = 756}
	button = Qt::LeftButton
	nextEvent = {type = -1075788124, xany = {type = -1075788124, serial = 6, send_event = -1239964041, 
    display = 0xbfe0da4c, window = 3050717044}, xkey = {type = -1075788124, serial = 6, 
    send_event = -1239964041, display = 0xbfe0da4c, window = 3050717044, root = 3219178760, 
    subwindow = 3063611380, time = 136581328, x = 71911216, y = -1075788488, x_root = -1239852936, 
    y_root = 136613216, state = 71911216, keycode = 362, same_screen = 6}, xbutton = {type = -1075788124, 
    serial = 6, send_event = -1239964041, display = 0xbfe0da4c, window = 3050717044, root = 3219178760, 
    subwindow = 3063611380, time = 136581328, x = 71911216, y = -1075788488, x_root = -1239852936, 
    y_root = 136613216, state = 71911216, button = 362, same_screen = 6}, xmotion = {type = -1075788124, 
    serial = 6, send_event = -1239964041, display = 0xbfe0da4c, window = 3050717044, root = 3219178760, 
    subwindow = 3063611380, time = 136581328, x = 71911216, y = -1075788488, x_root = -1239852936, 
    y_root = 136613216, state = 71911216, is_hint = 106 'j', same_screen = 6}, xcrossing = {type = -1075788124, 
    serial = 6, send_event = -1239964041, display = 0xbfe0da4c, window = 3050717044, root = 3219178760, 
    subwindow = 3063611380, time = 136581328, x = 71911216, y = -1075788488, x_root = -1239852936, 
    y_root = 136613216, mode = 71911216, detail = 362, same_screen = 6, focus = 32, state = 0}, xfocus = {
    type = -1075788124, serial = 6, send_event = -1239964041, display = 0xbfe0da4c, window = 3050717044, 
    mode = -1075788536, detail = -1231355916}, xexpose = {type = -1075788124, serial = 6, 
    send_event = -1239964041, display = 0xbfe0da4c, window = 3050717044, x = -1075788536, y = -1231355916, 
    width = 136581328, height = 71911216, count = -1075788488}, xgraphicsexpose = {type = -1075788124, 
    serial = 6, send_event = -1239964041, display = 0xbfe0da4c, drawable = 3050717044, x = -1075788536, 
    y = -1231355916, width = 136581328, height = 71911216, count = -1075788488, major_code = -1239852936, 
    minor_code = 136613216}, xnoexpose = {type = -1075788124, serial = 6, send_event = -1239964041, 
    display = 0xbfe0da4c, drawable = 3050717044, major_code = -1075788536, minor_code = -1231355916}, 
  xvisibility = {type = -1075788124, serial = 6, send_event = -1239964041, display = 0xbfe0da4c, 
    window = 3050717044, state = -1075788536}, xcreatewindow = {type = -1075788124, serial = 6, 
    send_event = -1239964041, display = 0xbfe0da4c, parent = 3050717044, window = 3219178760, x = -1231355916, 
    y = 136581328, width = 71911216, height = -1075788488, border_width = -1239852936, 
    override_redirect = 136613216}, xdestroywindow = {type = -1075788124, serial = 6, send_event = -1239964041, 
    display = 0xbfe0da4c, event = 3050717044, window = 3219178760}, xunmap = {type = -1075788124, serial = 6, 
    send_event = -1239964041, display = 0xbfe0da4c, event = 3050717044, window = 3219178760, 
    from_configure = -1231355916}, xmap = {type = -1075788124, serial = 6, send_event = -1239964041, 
    display = 0xbfe0da4c, event = 3050717044, window = 3219178760, override_redirect = -1231355916}, 
  xmaprequest = {type = -1075788124, serial = 6, send_event = -1239964041, display = 0xbfe0da4c, 
    parent = 3050717044, window = 3219178760}, xreparent = {type = -1075788124, serial = 6, 
    send_event = -1239964041, display = 0xbfe0da4c, event = 3050717044, window = 3219178760, 
    parent = 3063611380, x = 136581328, y = 71911216, override_redirect = -1075788488}, xconfigure = {
    type = -1075788124, serial = 6, send_event = -1239964041, display = 0xbfe0da4c, event = 3050717044, 
    window = 3219178760, x = -1231355916, y = 136581328, width = 71911216, height = -1075788488, 
    border_width = -1239852936, above = 136613216, override_redirect = 71911216}, xgravity = {
    type = -1075788124, serial = 6, send_event = -1239964041, display = 0xbfe0da4c, event = 3050717044, 
    window = 3219178760, x = -1231355916, y = 136581328}, xresizerequest = {type = -1075788124, serial = 6, 
    send_event = -1239964041, display = 0xbfe0da4c, window = 3050717044, width = -1075788536, 
    height = -1231355916}, xconfigurerequest = {type = -1075788124, serial = 6, send_event = -1239964041, 
    display = 0xbfe0da4c, parent = 3050717044, window = 3219178760, x = -1231355916, y = 136581328, 
    width = 71911216, height = -1075788488, border_width = -1239852936, above = 136613216, detail = 71911216, 
    value_mask = 362}, xcirculate = {type = -1075788124, serial = 6, send_event = -1239964041, 
    display = 0xbfe0da4c, event = 3050717044, window = 3219178760, place = -1231355916}, xcirculaterequest = {
    type = -1075788124, serial = 6, send_event = -1239964041, display = 0xbfe0da4c, parent = 3050717044, 
    window = 3219178760, place = -1231355916}, xproperty = {type = -1075788124, serial = 6, 
    send_event = -1239964041, display = 0xbfe0da4c, window = 3050717044, atom = 3219178760, time = 3063611380, 
    state = 136581328}, xselectionclear = {type = -1075788124, serial = 6, send_event = -1239964041, 
    display = 0xbfe0da4c, window = 3050717044, selection = 3219178760, time = 3063611380}, xselectionrequest = {
    type = -1075788124, serial = 6, send_event = -1239964041, display = 0xbfe0da4c, owner = 3050717044, 
    requestor = 3219178760, selection = 3063611380, target = 136581328, property = 71911216, time = 3219178808}, 
  xselection = {type = -1075788124, serial = 6, send_event = -1239964041, display = 0xbfe0da4c, 
    requestor = 3050717044, selection = 3219178760, target = 3063611380, property = 136581328, time = 71911216}, 
  xcolormap = {type = -1075788124, serial = 6, send_event = -1239964041, display = 0xbfe0da4c, 
    window = 3050717044, colormap = 3219178760, c_new = -1231355916, state = 136581328}, xclient = {
    type = -1075788124, serial = 6, send_event = -1239964041, display = 0xbfe0da4c, window = 3050717044, 
    message_type = 3219178760, format = -1231355916, data = {b = "�\020$\b0GI\0048���xX\031�`\215$\b", s = {
        4304, 2084, 18224, 1097, -15048, -16416, 22648, -18919, -29344, 2084}, l = {136581328, 71911216, 
        -1075788488, -1239852936, 136613216}}}, xmapping = {type = -1075788124, serial = 6, 
    send_event = -1239964041, display = 0xbfe0da4c, window = 3050717044, request = -1075788536, 
    first_keycode = -1231355916, count = 136581328}, xerror = {type = -1075788124, display = 0x6, 
    resourceid = 3055003255, serial = 3219184204, error_code = 116 't', request_code = 63 '?', 
    minor_code = 214 '�'}, xkeymap = {type = -1075788124, serial = 6, send_event = -1239964041, 
    display = 0xbfe0da4c, window = 3050717044, 
    key_vector = "\b�����\232��\020$\b0GI\0048���xX\031�`\215$\b0GI\004"}, pad = {-1075788124, 6, -1239964041, 
    -1075783092, -1244250252, -1075788536, -1231355916, 136581328, 71911216, -1075788488, -1239852936, 
    136613216, 71911216, 362, 6, 32, 0, -1075788476, 1, -1075782344, 51790476, -1075788488, -1240219801, 
    176102736}}
#10 0xb61a8085 in QApplication::x11ProcessEvent (this=0xbfe0dd38, event=0xbfe0da4c)
    at kernel/qapplication_x11.cpp:3428
	d = (class QApplicationPrivate * const) 0x823dbd0
	time = <value optimized out>
	userTime = <value optimized out>
	widget = (struct QETWidget *) 0xa7f1d50
	keywidget = (struct QETWidget *) 0x0
	grabbed = false
#11 0xb61d337a in x11EventSourceDispatch (s=0x8240800, callback=0, user_data=0x0)
    at kernel/qguieventdispatcher_glib.cpp:146
	event = {type = 4, xany = {type = 4, serial = 4360654, send_event = 0, display = 0x8248d60, 
    window = 71911216}, xkey = {type = 4, serial = 4360654, send_event = 0, display = 0x8248d60, 
    window = 71911216, root = 208, subwindow = 0, time = 51790476, x = 7, y = 12, x_root = 828, y_root = 756, 
    state = 0, keycode = 1, same_screen = 1}, xbutton = {type = 4, serial = 4360654, send_event = 0, 
    display = 0x8248d60, window = 71911216, root = 208, subwindow = 0, time = 51790476, x = 7, y = 12, 
    x_root = 828, y_root = 756, state = 0, button = 1, same_screen = 1}, xmotion = {type = 4, serial = 4360654, 
    send_event = 0, display = 0x8248d60, window = 71911216, root = 208, subwindow = 0, time = 51790476, x = 7, 
    y = 12, x_root = 828, y_root = 756, state = 0, is_hint = 1 '\001', same_screen = 1}, xcrossing = {type = 4, 
    serial = 4360654, send_event = 0, display = 0x8248d60, window = 71911216, root = 208, subwindow = 0, 
    time = 51790476, x = 7, y = 12, x_root = 828, y_root = 756, mode = 0, detail = 1, same_screen = 1, 
    focus = 0, state = 4096}, xfocus = {type = 4, serial = 4360654, send_event = 0, display = 0x8248d60, 
    window = 71911216, mode = 208, detail = 0}, xexpose = {type = 4, serial = 4360654, send_event = 0, 
    display = 0x8248d60, window = 71911216, x = 208, y = 0, width = 51790476, height = 7, count = 12}, 
  xgraphicsexpose = {type = 4, serial = 4360654, send_event = 0, display = 0x8248d60, drawable = 71911216, 
    x = 208, y = 0, width = 51790476, height = 7, count = 12, major_code = 828, minor_code = 756}, xnoexpose = {
    type = 4, serial = 4360654, send_event = 0, display = 0x8248d60, drawable = 71911216, major_code = 208, 
    minor_code = 0}, xvisibility = {type = 4, serial = 4360654, send_event = 0, display = 0x8248d60, 
    window = 71911216, state = 208}, xcreatewindow = {type = 4, serial = 4360654, send_event = 0, 
    display = 0x8248d60, parent = 71911216, window = 208, x = 0, y = 51790476, width = 7, height = 12, 
    border_width = 828, override_redirect = 756}, xdestroywindow = {type = 4, serial = 4360654, send_event = 0, 
    display = 0x8248d60, event = 71911216, window = 208}, xunmap = {type = 4, serial = 4360654, send_event = 0, 
    display = 0x8248d60, event = 71911216, window = 208, from_configure = 0}, xmap = {type = 4, 
    serial = 4360654, send_event = 0, display = 0x8248d60, event = 71911216, window = 208, 
    override_redirect = 0}, xmaprequest = {type = 4, serial = 4360654, send_event = 0, display = 0x8248d60, 
    parent = 71911216, window = 208}, xreparent = {type = 4, serial = 4360654, send_event = 0, 
    display = 0x8248d60, event = 71911216, window = 208, parent = 0, x = 51790476, y = 7, 
    override_redirect = 12}, xconfigure = {type = 4, serial = 4360654, send_event = 0, display = 0x8248d60, 
    event = 71911216, window = 208, x = 0, y = 51790476, width = 7, height = 12, border_width = 828, 
    above = 756, override_redirect = 0}, xgravity = {type = 4, serial = 4360654, send_event = 0, 
    display = 0x8248d60, event = 71911216, window = 208, x = 0, y = 51790476}, xresizerequest = {type = 4, 
    serial = 4360654, send_event = 0, display = 0x8248d60, window = 71911216, width = 208, height = 0}, 
  xconfigurerequest = {type = 4, serial = 4360654, send_event = 0, display = 0x8248d60, parent = 71911216, 
    window = 208, x = 0, y = 51790476, width = 7, height = 12, border_width = 828, above = 756, detail = 0, 
    value_mask = 1}, xcirculate = {type = 4, serial = 4360654, send_event = 0, display = 0x8248d60, 
    event = 71911216, window = 208, place = 0}, xcirculaterequest = {type = 4, serial = 4360654, send_event = 0, 
    display = 0x8248d60, parent = 71911216, window = 208, place = 0}, xproperty = {type = 4, serial = 4360654, 
    send_event = 0, display = 0x8248d60, window = 71911216, atom = 208, time = 0, state = 51790476}, 
  xselectionclear = {type = 4, serial = 4360654, send_event = 0, display = 0x8248d60, window = 71911216, 
    selection = 208, time = 0}, xselectionrequest = {type = 4, serial = 4360654, send_event = 0, 
    display = 0x8248d60, owner = 71911216, requestor = 208, selection = 0, target = 51790476, property = 7, 
    time = 12}, xselection = {type = 4, serial = 4360654, send_event = 0, display = 0x8248d60, 
    requestor = 71911216, selection = 208, target = 0, property = 51790476, time = 7}, xcolormap = {type = 4, 
    serial = 4360654, send_event = 0, display = 0x8248d60, window = 71911216, colormap = 208, c_new = 0, 
    state = 51790476}, xclient = {type = 4, serial = 4360654, send_event = 0, display = 0x8248d60, 
    window = 71911216, message_type = 208, format = 0, data = {
      b = "\214B\026\003\a\000\000\000\f\000\000\000<\003\000\000�\002\000", s = {17036, 790, 7, 0, 12, 0, 828, 
        0, 756, 0}, l = {51790476, 7, 12, 828, 756}}}, xmapping = {type = 4, serial = 4360654, send_event = 0, 
    display = 0x8248d60, window = 71911216, request = 208, first_keycode = 0, count = 51790476}, xerror = {
    type = 4, display = 0x4289ce, resourceid = 0, serial = 136613216, error_code = 48 '0', 
    request_code = 71 'G', minor_code = 73 'I'}, xkeymap = {type = 4, serial = 4360654, send_event = 0, 
    display = 0x8248d60, window = 71911216, 
    key_vector = "�\000\000\000\000\000\000\000\214B\026\003\a\000\000\000\f\000\000\000<\003\000\000�\002\000\000\000\000\000"}, pad = {4, 4360654, 0, 136613216, 71911216, 208, 0, 51790476, 7, 12, 828, 756, 0, 1, 1, 0, 4096, 
    0, 0, 0, 0, 0, 0, 0}}
	marker = 4360655
#12 0xb4d41b88 in IA__g_main_context_dispatch (context=0x823fc90)
    at /build/buildd/glib2.0-2.20.1/glib/gmain.c:1814
No locals.
#13 0xb4d450eb in g_main_context_iterate (context=0x823fc90, block=1, dispatch=1, self=0x823db08)
    at /build/buildd/glib2.0-2.20.1/glib/gmain.c:2448
	max_priority = 2147483647
	timeout = 99
	some_ready = 1
	nfds = 19
	allocated_nfds = <value optimized out>
	fds = (GPollFD *) 0x925cf80
	__PRETTY_FUNCTION__ = "g_main_context_iterate"
#14 0xb4d45268 in IA__g_main_context_iteration (context=0x823fc90, may_block=1)
    at /build/buildd/glib2.0-2.20.1/glib/gmain.c:2511
	retval = <value optimized out>
#15 0xb5c9b2f8 in QEventDispatcherGlib::processEvents (this=0x821e028, flags={i = -1075782648})
    at kernel/qeventdispatcher_glib.cpp:327
	d = (QEventDispatcherGlibPrivate * const) 0x823d670
	canWait = true
	result = <value optimized out>
#16 0xb61d2a75 in QGuiEventDispatcherGlib::processEvents (this=0x821e028, flags={i = -1075782600})
    at kernel/qguieventdispatcher_glib.cpp:202
	d = (QGuiEventDispatcherGlibPrivate * const) 0x823d670
	returnValue = true
#17 0xb5c6e1fa in QEventLoop::processEvents (this=0xbfe0dcb0, flags={i = -1075782536})
    at kernel/qeventloop.cpp:149
	d = (QEventLoopPrivate * const) 0x82e4f40
#18 0xb5c6e642 in QEventLoop::exec (this=0xbfe0dcb0, flags={i = -1075782472}) at kernel/qeventloop.cpp:201
	d = (QEventLoopPrivate * const) 0x82e4f40
	app = (class QCoreApplication *) 0xbfe0dd38
#19 0xb5c70ae9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
	threadData = (QThreadData *) 0x821e440
	eventLoop = {<QObject> = {_vptr.QObject = 0xb5d627a8, static staticMetaObject = {d = {superdata = 0x0, 
        stringdata = 0xb5d0ac00 "QObject", data = 0xb5d0aca0, extradata = 0xb5d5e1b8}}, d_ptr = 0x82e4f40, 
    static staticQtMetaObject = {d = {superdata = 0x0, stringdata = 0xb5d143e0 "Qt", data = 0xb5d172c0, 
        extradata = 0x0}}}, static staticMetaObject = {d = {superdata = 0xb5d5e1a8, 
      stringdata = 0xb5d1c080 "QEventLoop", data = 0xb5d1c0a0, extradata = 0x0}}}
	returnCode = -1
#20 0xb6130bb7 in QApplication::exec () at kernel/qapplication.cpp:3525
No locals.
#21 0x0804bfef in main (argc=1, argv=0xbfe0e034) at /build/buildd/kdepim-4.3.0/kontact/src/main.cpp:218
	about = {d = 0x8221b78}
	args = (KCmdLineArgs *) 0x8235298
	app = {<KUniqueApplication> = {<KApplication> = {<QApplication> = {<QCoreApplication> = {<QObject> = {
            _vptr.QObject = 0x804c8c8, static staticMetaObject = {d = {superdata = 0x0, 
                stringdata = 0xb5d0ac00 "QObject", data = 0xb5d0aca0, extradata = 0xb5d5e1b8}}, 
            d_ptr = 0x823dbd0, static staticQtMetaObject = {d = {superdata = 0x0, stringdata = 0xb5d143e0 "Qt", 
                data = 0xb5d172c0, extradata = 0x0}}}, static staticMetaObject = {d = {superdata = 0xb5d5e1a8, 
              stringdata = 0xb5d1c100 "QCoreApplication", data = 0xb5d1c1a0, extradata = 0x0}}, 
          static self = 0xbfe0dd38}, static staticMetaObject = {d = {superdata = 0xb5d627e4, 
            stringdata = 0xb67ce240 "QApplication", data = 0xb67ce440, extradata = 0x0}}}, 
      static staticMetaObject = {d = {superdata = 0xb6999f48, stringdata = 0xb6ead620 "KApplication", 
          data = 0xb6ead7c0, extradata = 0x0}}, static loadedByKdeinit = false, static KApp = 0xbfe0dd38, 
      d = 0x828de60}, static staticMetaObject = {d = {superdata = 0xb6ed5ba0, 
        stringdata = 0xb6eadf00 "KUniqueApplication", data = 0xb6eae000, extradata = 0x0}}, d = 0x82a55f0}, 
  static staticMetaObject = {d = {superdata = 0x804e298, stringdata = 0x804c7a0 "KontactApp", data = 0x804c860, 
      extradata = 0x0}}, mMainWindow = 0x82a7608, mSessionRestored = false}

Changing product. There's nothing related to Kontact in these backtraces.

This is an X11 bug. If this is still happening, please report to https://bugs.freedesktop.org/