mlind@sandbox:~/tmp/bug$ gdb gnome-volume-control
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This GDB was configured as "i486-linux-gnu"...Using host libthread_db library "/lib/tls/i686/cmov/libthread_db.so.1".
(gdb) handle SIG33 pass nostop noprint
Signal        Stop      Print   Pass to program Description
SIG33         No        No      Yes             Real-time event 33
(gdb) run
Starting program: /usr/bin/gnome-volume-control
[Thread debugging using libthread_db enabled]
[New Thread -1224403264 (LWP 9804)]

(gnome-volume-control:9804): GLib-GObject-WARNING **: invalid uninstantiatable type `(null)' in cast to `GnomeVolumeControlVolume'

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1224403264 (LWP 9804)]
0x08051d9e in gnome_volume_control_volume_ask (vol=0x80ed9b0, real_zero=0xbf9ab614, slider_zero=0xbf9ab610)
    at volume.c:544
544       volumes = g_new (gint, vol->track->num_channels);
(gdb) thread apply all bt

Thread 1 (Thread -1224403264 (LWP 9804)):
#0  0x08051d9e in gnome_volume_control_volume_ask (vol=0x80ed9b0, real_zero=0xbf9ab614, slider_zero=0xbf9ab610)
    at volume.c:544
#1  0x0804f957 in cb_check (data=0x8233cd0) at track.c:119
#2  0xb727e3a8 in g_main_context_is_owner () from /usr/lib/libglib-2.0.so.0
#3  0xb727c7d7 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#4  0xb727f896 in g_main_context_check () from /usr/lib/libglib-2.0.so.0
#5  0xb727fbb8 in g_main_loop_run () from /usr/lib/libglib-2.0.so.0
#6  0xb797e3c6 in gtk_main () from /usr/lib/libgtk-x11-2.0.so.0
#7  0x0804eab2 in main (argc=1, argv=0xbf9ab894) at main.c:217
(gdb)