This looks to be a race condition before QApplication() is finished. The following is a stack trace (missing a few debug symbols) from a hung program. I notice the call to g_bus_get_sync near the top of the stack, which a quick search reveals is related to the DBus integration. Also possibly related to or the same bug as Bug #1115647 #0 0x00007f33bddfb89c in __lll_lock_wait () from /lib/x86_64-linux-gnu/libpthread.so.0 #1 0x00007f33bddf709b in _L_lock_1006 () from /lib/x86_64-linux-gnu/libpthread.so.0 #2 0x00007f33bddf701c in pthread_mutex_lock () from /lib/x86_64-linux-gnu/libpthread.so.0 #3 0x00007f33bcb54e21 in g_mutex_lock (mutex=mutex@entry=0x164f1c0) at /build/buildd/glib2.0-2.34.1/./glib/gthread-posix.c:208 #4 0x00007f33b6824c2d in initable_init (initable=0x164f1a0, cancellable=0x0, error=0x0) at /build/buildd/glib2.0-2.34.1/./gio/gdbusconnection.c:2527 #5 0x00007f33b68255c1 in g_bus_get_sync (bus_type=, cancellable=0x0, error=0x0) at /build/buildd/glib2.0-2.34.1/./gio/gdbusconnection.c:6882 #6 0x00007f33b0e20518 in ?? () from /usr/lib/x86_64-linux-gnu/gio/modules/libgvfsdbus.so #7 0x00007f33bc1d898f in g_type_create_instance (type=) at /build/buildd/glib2.0-2.34.1/./gobject/gtype.c:1890 #8 0x00007f33bc1bd288 in g_object_constructor (type=, n_construct_properties=0, construct_params=0x0) at /build/buildd/glib2.0-2.34.1/./gobject/gobject.c:1854 #9 0x00007f33bc1bed41 in g_object_newv ( object_type=object_type@entry=23889072, n_parameters=n_parameters@entry=0, parameters=parameters@entry=0x0) at /build/buildd/glib2.0-2.34.1/./gobject/gobject.c:1637 #10 0x00007f33bc1bf38c in g_object_new ( object_type=object_type@entry=23889072, first_property_name=first_property_name@entry=0x0) at /build/buildd/glib2.0-2.34.1/./gobject/gobject.c:1547 #11 0x00007f33b67bff11 in try_implementation (extension=, verify_func=verify_func@entry=0x7f33b67e8a30 ) at /build/buildd/glib2.0-2.34.1/./gio/giomodule.c:645 #12 0x00007f33b67c00a0 in _g_io_module_get_default ( extension_point=extension_point@entry=0x7f33b685cb8c "gio-vfs", envvar=envvar@entry=0x7f33b6865222 "GIO_USE_VFS", verify_func=verify_func@entry=0x7f33b67e8a30 ) at /build/buildd/glib2.0-2.34.1/./gio/giomodule.c:742 #13 0x00007f33b67e8e6e in g_vfs_get_default () at /build/buildd/glib2.0-2.34.1/./gio/gvfs.c:199 #14 0x00007f33b67ac6ae in g_file_new_for_path ( path=0x16ba9b0 "/home/hunter/.config/ibus/bus/462ed6a22686e37540be4d5f51016f7c-unix-0") at /build/buildd/glib2.0-2.34.1/./gio/gfile.c:6092 #15 0x00007f33b1064baa in ?? () from /usr/lib/x86_64-linux-gnu/libibus-1.0.so.0 #16 0x00007f33bc1d898f in g_type_create_instance (type=) at /build/buildd/glib2.0-2.34.1/./gobject/gtype.c:1890 #17 0x00007f33bc1bd288 in g_object_constructor (type=, n_construct_properties=0, construct_params=0x0) at /build/buildd/glib2.0-2.34.1/./gobject/gobject.c:1854 #18 0x00007f33b1062b45 in ?? () from /usr/lib/x86_64-linux-gnu/libibus-1.0.so.0 #19 0x00007f33bc1bed41 in g_object_newv ( object_type=object_type@entry=23874144, n_parameters=n_parameters@entry=0, parameters=parameters@entry=0x0) at /build/buildd/glib2.0-2.34.1/./gobject/gobject.c:1637 #20 0x00007f33bc1bf38c in g_object_new (object_type=23874144, first_property_name=0x0) at /build/buildd/glib2.0-2.34.1/./gobject/gobject.c:1547 #21 0x00007f33b1062b9a in ibus_bus_new () from /usr/lib/x86_64-linux-gnu/libibus-1.0.so.0 #22 0x00007f33b12a70da in ?? () from /usr/lib/x86_64-linux-gnu/gtk-2.0/2.10.0/immodules/im-ibus.so #23 0x00007f33bc1d6926 in type_class_init_Wm (pclass=0x16af7b0, node=0x16c4600) at /build/buildd/glib2.0-2.34.1/./gobject/gtype.c:2217 #24 g_type_class_ref (type=type@entry=23873024) at /build/buildd/glib2.0-2.34.1/./gobject/gtype.c:2924 #25 0x00007f33bc1bedf1 in g_object_newv ( object_type=object_type@entry=23873024, n_parameters=n_parameters@entry=0, parameters=parameters@entry=0x0) at /build/buildd/glib2.0-2.34.1/./gobject/gobject.c:1623 #26 0x00007f33bc1bf38c in g_object_new (object_type=23873024, first_property_name=0x0) at /build/buildd/glib2.0-2.34.1/./gobject/gobject.c:1547 #27 0x00007f33b12a7b92 in ibus_im_context_new () from /usr/lib/x86_64-linux-gnu/gtk-2.0/2.10.0/immodules/im-ibus.so #28 0x00007f33b5e0e026 in _gtk_im_module_create (context_id=) at /build/buildd/gtk+2.0-2.24.13/gtk/gtkimmodule.c:614 #29 0x00007f33b5e0e909 in gtk_im_multicontext_get_slave ( multicontext=multicontext@entry=0x1680300) at /build/buildd/gtk+2.0-2.24.13/gtk/gtkimmulticontext.c:254 #30 0x00007f33b5e0ebad in gtk_im_multicontext_set_client_window ( context=0x1680300, window=0x1679120) at /build/buildd/gtk+2.0-2.24.13/gtk/gtkimmulticontext.c:300 #31 0x00007f33b5db3fda in gtk_entry_realize (widget=0x1684050) at /build/buildd/gtk+2.0-2.24.13/gtk/gtkentry.c:2809 #32 0x00007f33bc1b8140 in g_closure_invoke (closure=0x15f1ba0, return_value=0x0, n_param_values=1, param_values=0x7fffd9f43600, invocation_hint=0x7fffd9f435a0) at /build/buildd/glib2.0-2.34.1/./gobject/gclosure.c:777 #33 0x00007f33bc1c8e73 in signal_emit_unlocked_R (node=node@entry=0x15f1bd0, detail=detail@entry=0, instance=instance@entry=0x1684050, emission_return=emission_return@entry=0x0, instance_and_params=instance_and_params@entry=0x7fffd9f43600) at /build/buildd/glib2.0-2.34.1/./gobject/gsignal.c:3481 #34 0x00007f33bc1d14af in g_signal_emit_valist (instance=0x1684050, signal_id=, detail=0, var_args=var_args@entry=0x7fffd9f43848) at /build/buildd/glib2.0-2.34.1/./gobject/gsignal.c:3300 #35 0x00007f33bc1d1642 in g_signal_emit (instance=instance@entry=0x1684050, signal_id=, detail=detail@entry=0) at /build/buildd/glib2.0-2.34.1/./gobject/gsignal.c:3356 #36 0x00007f33b5f465d0 in IA__gtk_widget_realize (widget=0x1684050) at /build/buildd/gtk+2.0-2.24.13/gtk/gtkwidget.c:3554 #37 0x00007f33bea32643 in QGtkStylePrivate::addWidgetToMap ( widget=widget@entry=0x1684050) at styles/qgtkstyle_p.cpp:771 #38 0x00007f33bea32839 in QGtkStylePrivate::addAllSubWidgets ( widget=0x1684050, v=) at styles/qgtkstyle_p.cpp:785 #39 0x00007f33bea32c55 in QGtkStylePrivate::initGtkWidgets (this=0x15b59e0) at styles/qgtkstyle_p.cpp:555 #40 0x00007f33bea17cd9 in QGtkStyle::QGtkStyle (this=0x15af6f0) at styles/qgtkstyle.cpp:193 #41 0x00007f33be99ec0b in QStyleFactory::create (key=...) at styles/qstylefactory.cpp:177 #42 0x00007f33be6ab9f3 in QApplication::style () at kernel/qapplication.cpp:1467 #43 0x00007f33be6ae375 in QApplicationPrivate::initialize ( this=this@entry=0x1541d20) at kernel/qapplication.cpp:988 #44 0x00007f33be6ae4b2 in QApplicationPrivate::construct (this=0x1541d20, dpy=dpy@entry=0x0, visual=visual@entry=0, cmap=cmap@entry=0) at kernel/qapplication.cpp:840 #45 0x00007f33be6aed74 in QApplication::QApplication (this=0x7fffd9f43c50, argc=@0x7fffd9f43c4c: 1, argv=0x7fffd9f43e08, _internal=17041411) at kernel/qapplication.cpp:738 #46 0x00000000004053b7 in main (argc=1, argv=0x7fffd9f43e08)