The core file is big (~65M). So I'd like to paste the backtrace here.

(gdb) where
#0  0x08132293 in ?? ()
#1  0x008740fc in g_cclosure_marshal_VOID__STRING ()
   from /usr/lib/libgobject-2.0.so.0
#2  0x008641b2 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#3  0x0087cde5 in ?? () from /usr/lib/libgobject-2.0.so.0
#4  0x0087e45c in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#5  0x0087ebc2 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#6  0x0025a152 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#7  0x0087371c in g_cclosure_marshal_VOID__VOID ()
   from /usr/lib/libgobject-2.0.so.0
#8  0x008641b2 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#9  0x0087cde5 in ?? () from /usr/lib/libgobject-2.0.so.0
#10 0x0087e45c in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#11 0x0087e745 in g_signal_emit_by_name () from /usr/lib/libgobject-2.0.so.0
#12 0x002c3a07 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#13 0x0087371c in g_cclosure_marshal_VOID__VOID ()
   from /usr/lib/libgobject-2.0.so.0
#14 0x008641b2 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#15 0x0087cde5 in ?? () from /usr/lib/libgobject-2.0.so.0
#16 0x0087e45c in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#17 0x0087ebc2 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#18 0x07d4e17b in ?? () from /usr/lib/gtk-2.0/2.10.0/immodules/im-ibus.so
#19 0x0087371c in g_cclosure_marshal_VOID__VOID ()
   from /usr/lib/libgobject-2.0.so.0
#20 0x008641b2 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#21 0x0087cde5 in ?? () from /usr/lib/libgobject-2.0.so.0
#22 0x0087e45c in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#23 0x0087ebc2 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#24 0x03c56a7d in ?? () from /usr/lib/libibus.so.2
#25 0x03c64d74 in ibus_marshal_BOOLEAN__POINTER () from /usr/lib/libibus.so.2
#26 0x00862827 in ?? () from /usr/lib/libgobject-2.0.so.0
#27 0x008641b2 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#28 0x0087ca36 in ?? () from /usr/lib/libgobject-2.0.so.0
#29 0x0087e2db in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#30 0x0087ebc2 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#31 0x03c4b30d in ibus_proxy_handle_signal () from /usr/lib/libibus.so.2
#32 0x03c4bb34 in ?? () from /usr/lib/libibus.so.2
#33 0x03c64d74 in ibus_marshal_BOOLEAN__POINTER () from /usr/lib/libibus.so.2
#34 0x008641b2 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#35 0x0087cde5 in ?? () from /usr/lib/libgobject-2.0.so.0
#36 0x0087e2db in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#37 0x0087ebc2 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#38 0x03c49b98 in ?? () from /usr/lib/libibus.so.2
#39 0x03c64d74 in ibus_marshal_BOOLEAN__POINTER () from /usr/lib/libibus.so.2
#40 0x00862827 in ?? () from /usr/lib/libgobject-2.0.so.0
#41 0x008641b2 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#42 0x0087ca36 in ?? () from /usr/lib/libgobject-2.0.so.0
#43 0x0087e2db in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#44 0x0087ebc2 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#45 0x03c481d4 in ?? () from /usr/lib/libibus.so.2
#46 0x00aa6358 in dbus_connection_dispatch () from /lib/libdbus-1.so.3
#47 0x03c4631d in ?? () from /usr/lib/libibus.so.2
#48 0x007b39b5 in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#49 0x007b77c8 in ?? () from /lib/libglib-2.0.so.0
#50 0x007b7d07 in g_main_loop_run () from /lib/libglib-2.0.so.0
#51 0x002de749 in gtk_main () from /usr/lib/libgtk-x11-2.0.so.0
#52 0x0807f587 in ?? ()
#53 0x05f4fce7 in __libc_start_main () from /lib/libc.so.6
#54 0x0806a6a1 in ?? ()