Comment 5 for bug 792999

I cannot access bug 793981 since it's private, so I don't know if it has a good stack trace (or just good enough for "Apport retracing service" to have identified this as a duplicate). In case it helps, here's a retrace (from a later occurrence of the crash):

#0 0x00611416 in __kernel_vsyscall ()
#1 0x0119cdd1 in raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#2 0x011a02ae in abort () at abort.c:92
#3 0x0807d7eb in meta_bug (
    format=0x80b09a0 "Unexpected X error: %s serial %ld error_code %d request_code %d minor_code %d)\n") at core/util.c:398
#4 0x0806971c in x_error_handler (xdisplay=0x9e02128, error=0xbffdaa0c)
    at core/errors.c:247
#5 x_error_handler (xdisplay=0x9e02128, error=0xbffdaa0c) at core/errors.c:203
#6 0x00f419fb in _XError (dpy=0x9e02128, rep=0x9f3ae28)
    at ../../src/XlibInt.c:1583
#7 0x00f3e6bd in handle_error (dpy=0x9e02128, err=0x9f3ae28, in_XReply=0)
    at ../../src/xcb_io.c:166
#8 0x00f3e717 in handle_response (dpy=0x9e02128, response=0x9f3ae28,
    in_XReply=0) at ../../src/xcb_io.c:266
#9 0x00f3f098 in _XReadEvents (dpy=0x9e02128) at ../../src/xcb_io.c:382
#10 0x00f3d723 in XWindowEvent (dpy=0x9e02128, w=16777220, mask=4194304,
    event=0xbffdabac) at ../../src/WinEvent.c:79
#11 0x0806059c in meta_display_get_current_time_roundtrip (display=0x9e61538)
    at core/display.c:1217
#12 0x08089ca4 in meta_window_show (window=0x9ebdb78, showing=1)
    at core/window.c:2165
#13 implement_showing (window=0x9ebdb78, showing=1) at core/window.c:1583
#14 0x0808770c in meta_window_flush_calc_showing (window=0x9ebdb78,
    timestamp=1395620) at core/window.c:1806
#15 meta_window_focus (window=0x9ebdb78, timestamp=1395620)
    at core/window.c:4234
#16 0x0808963d in window_activate (window=0x9ebdb78, timestamp=1395620,
    source_indication=META_CLIENT_TYPE_APPLICATION, workspace=0x9e0f348)
    at core/window.c:3104
#17 0x0808b0e5 in meta_window_client_message (window=0x9ebdb78,
    event=0xbffdb0fc) at core/window.c:5373
#18 0x08063564 in event_callback (event=0xbffdb0fc, data=0x9e61538)
    at core/display.c:2180
#19 0x080aa95e in filter_func (xevent=0xbffdb0fc, event=0x9e14e88,
    data=0x9e6dba0) at ui/ui.c:222
#20 0x002b690e in gdk_event_apply_filters (display=0x9e0e0b0, event=0x9e14e88,
    xevent=0xbffdb0fc, return_exposes=0)
    at /build/buildd/gtk+2.0-2.24.5/gdk/x11/gdkevents-x11.c:356
#21 gdk_event_translate (display=0x9e0e0b0, event=0x9e14e88,
    xevent=0xbffdb0fc, return_exposes=0)
    at /build/buildd/gtk+2.0-2.24.5/gdk/x11/gdkevents-x11.c:927
#22 0x002b87eb in _gdk_events_queue (display=0x9e0e0b0)
    at /build/buildd/gtk+2.0-2.24.5/gdk/x11/gdkevents-x11.c:2310
#23 0x002b889d in gdk_event_dispatch (source=0x9e17518, callback=0,
    user_data=0x0) at /build/buildd/gtk+2.0-2.24.5/gdk/x11/gdkevents-x11.c:2371
#24 0x007080cf in g_main_dispatch (context=0x9df29d0)
    at /build/buildd/glib2.0-2.29.8/./glib/gmain.c:2477
#25 g_main_context_dispatch (context=0x9df29d0)
    at /build/buildd/glib2.0-2.29.8/./glib/gmain.c:3050
#26 0x00708800 in g_main_context_iterate (context=0x9df29d0, block=7435264,
    dispatch=1, self=<value optimized out>)
    at /build/buildd/glib2.0-2.29.8/./glib/gmain.c:3128
#27 0x00708e0b in g_main_loop_run (loop=0x9df3118)
    at /build/buildd/glib2.0-2.29.8/./glib/gmain.c:3336
#28 0x08053408 in main (argc=1, argv=0xbffdb754) at core/main.c:584