Comment 10 for bug 435227

Hm, I still get the crash with after either adding or removing the second user from admin. Unfortunately the stack trace is still mostly useless:

(polkit-gnome-authentication-agent-1:16940): GLib-CRITICAL **: g_once_init_leave: assertion `initialization_value != 0' failed

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff66d73c6 in ?? () from /lib/libc.so.6
(gdb) bt
#0 0x00007ffff66d73c6 in ?? () from /lib/libc.so.6
#1 0x00007ffff66d97ee in malloc () from /lib/libc.so.6
#2 0x00007ffff28d40f2 in ?? () from /usr/lib/libxcb.so.1
#3 0x00007ffff28d42c8 in xcb_poll_for_event () from /usr/lib/libxcb.so.1
#4 0x00007ffff5eba9bd in ?? () from /usr/lib/libX11.so.6
#5 0x00007ffff5ebb257 in _XEventsQueued () from /usr/lib/libX11.so.6
#6 0x00007ffff5ea3f9d in XPending () from /usr/lib/libX11.so.6
#7 0x00007ffff640c6d8 in ?? () from /usr/lib/libgdk-x11-2.0.so.0
#8 0x00007ffff6a0ca9a in IA__g_main_context_check (context=0x64fec0, max_priority=2147483647,
    fds=<value optimized out>, n_fds=32767) at /build/buildd/glib2.0-2.22.0/glib/gmain.c:2469
#9 0x00007ffff6a0d280 in g_main_context_iterate (context=0x64fec0, block=<value optimized out>,
    dispatch=<value optimized out>, self=<value optimized out>)
    at /build/buildd/glib2.0-2.22.0/glib/gmain.c:2588
#10 0x00007ffff6a0d9e5 in IA__g_main_loop_run (loop=0x6a3380)
    at /build/buildd/glib2.0-2.22.0/glib/gmain.c:2799
#11 0x0000000000407e98 in main (argc=1, argv=0x7fffffffe628) at main.c:255
(gdb) bt full
#0 0x00007ffff66d73c6 in ?? () from /lib/libc.so.6
No symbol table info available.
#1 0x00007ffff66d97ee in malloc () from /lib/libc.so.6
No symbol table info available.
#2 0x00007ffff28d40f2 in ?? () from /usr/lib/libxcb.so.1
No symbol table info available.
#3 0x00007ffff28d42c8 in xcb_poll_for_event () from /usr/lib/libxcb.so.1
No symbol table info available.
#4 0x00007ffff5eba9bd in ?? () from /usr/lib/libX11.so.6
No symbol table info available.
#5 0x00007ffff5ebb257 in _XEventsQueued () from /usr/lib/libX11.so.6
No symbol table info available.
#6 0x00007ffff5ea3f9d in XPending () from /usr/lib/libX11.so.6
No symbol table info available.
#7 0x00007ffff640c6d8 in ?? () from /usr/lib/libgdk-x11-2.0.so.0
No symbol table info available.
#8 0x00007ffff6a0ca9a in IA__g_main_context_check (context=0x64fec0, max_priority=2147483647,
    fds=<value optimized out>, n_fds=32767) at /build/buildd/glib2.0-2.22.0/glib/gmain.c:2469
        result = <value optimized out>
        check = 0x20
        source = 0x64fe40
        pollrec = <value optimized out>
        n_ready = 0
        i = <value optimized out>
#9 0x00007ffff6a0d280 in g_main_context_iterate (context=0x64fec0, block=<value optimized out>,
    dispatch=<value optimized out>, self=<value optimized out>)
    at /build/buildd/glib2.0-2.22.0/glib/gmain.c:2588
        max_priority = 2147483647
        timeout = -1
        some_ready = <value optimized out>
        nfds = 3
        allocated_nfds = -157179600
        fds = 0x8db4c0
        __PRETTY_FUNCTION__ = "g_main_context_iterate"
#10 0x00007ffff6a0d9e5 in IA__g_main_loop_run (loop=0x6a3380)
    at /build/buildd/glib2.0-2.22.0/glib/gmain.c:2799
        self = 0x631180
        __PRETTY_FUNCTION__ = "IA__g_main_loop_run"
#11 0x0000000000407e98 in main (argc=1, argv=0x7fffffffe628) at main.c:255
        ret = 0
        loop = 0x6a3380
        listener = 0x6ab2a0
        error = 0x0