$ DISPLAY=:0 gdb pcmanfm
GNU gdb (GDB) Fedora (7.5.0.20120926-25.fc18)
Copyright (C) 2012 Free Software Foundation, Inc.
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<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/bin/pcmanfm...done.
(gdb) run --desktop
Starting program: /usr/bin/pcmanfm --desktop
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/libthread_db.so.1".
warning: cannot close "/usr/lib/gio/modules/libgvfsdbus.so": Invalid operation
warning: cannot close "/usr/lib/gio/modules/libgiofam.so": Invalid operation
warning: cannot close "/lib/libfam.so.0": Invalid operation
[New Thread 0xb36cfb40 (LWP 20880)]
[New Thread 0xb2eceb40 (LWP 20881)]
[Thread 0xb2eceb40 (LWP 20881) exited]
[New Thread 0xb2eceb40 (LWP 20882)]
[Thread 0xb2eceb40 (LWP 20882) exited]
[New Thread 0xadc8fb40 (LWP 20883)]
[Thread 0xadc8fb40 (LWP 20883) exited]
[Thread 0xb36cfb40 (LWP 20880) exited]

Program received signal SIGSEGV, Segmentation fault.
0x0805e850 in get_nearest_item (dir=GTK_DIR_DOWN, desktop=0x80bb140, item=<optimized out>) at desktop.c:1557
1557                if(item2->y <= item->y)
Missing separate debuginfos, use: debuginfo-install atk-2.6.0-1.fc18.i686 cairo-1.12.8-1.fc18.i686 expat-2.1.0-4.fc18.i686 fontconfig-2.10.1-2.fc18.i686 freetype-2.4.10-2.fc18.i686 gamin-0.1.10-13.fc18.i686 gdk-pixbuf2-2.26.4-1.fc18.i686 glib2-2.34.1-1.fc18.i686 glibc-2.16-20.fc18.i686 gtk-murrine-engine-0.98.2-2.fc18.i686 gtk2-2.24.13-1.fc18.i686 gvfs-1.14.1-2.fc18.i686 harfbuzz-0.9.5-1.fc18.i686 libX11-1.5.0-3.fc18.i686 libXau-1.0.6-4.fc18.i686 libXcomposite-0.4.3-4.fc18.i686 libXcursor-1.1.13-2.fc18.i686 libXdamage-1.1.3-4.fc18.i686 libXext-1.3.1-2.fc18.i686 libXfixes-5.0-3.fc18.i686 libXi-1.6.1-2.fc18.i686 libXinerama-1.1.2-2.fc18.i686 libXrandr-1.4.0-1.fc18.i686 libXrender-0.9.7-2.fc18.i686 libbluray-0.2.3-1.fc18.i686 libdrm-2.4.40-1.fc18.i686 libexif-0.6.21-2.fc18.i686 libffi-3.0.10-3.fc18.i686 libgcc-4.7.2-3.fc18.i686 libicu-49.1.1-5.fc18.i686 libpng-1.5.13-1.fc18.i686 libselinux-2.1.12-7.fc18.i686 libstdc++-4.7.2-3.fc18.i686 libwayland-client-1.0.0-1.fc18.i686 libwayland-server-1.0.0-1.fc18.i686 libxcb-1.9-1.fc18.i686 libxml2-2.9.0-1.fc18.i686 mesa-libEGL-9.0-3.fc18.i686 mesa-libgbm-9.0-3.fc18.i686 mesa-libglapi-9.0-3.fc18.i686 pango-1.32.1-1.fc18.i686 pcre-8.31-2.fc18.i686 pixman-0.26.2-5.fc18.i686 systemd-libs-195-2.fc18.i686 xz-libs-5.1.2-2alpha.fc18.i686 zlib-1.2.7-9.fc18.i686
(gdb) bt
#0  0x0805e850 in get_nearest_item (dir=GTK_DIR_DOWN, desktop=0x80bb140, item=<optimized out>) at desktop.c:1557
#1  on_key_press (w=0x80bb140, evt=0x80b9240) at desktop.c:2146
#2  0xb7ad1ee2 in _gtk_marshal_BOOLEAN__BOXED () from /lib/libgtk-x11-2.0.so.0
#3  0xb7429e3e in g_type_class_meta_marshal () from /lib/libgobject-2.0.so.0
#4  0xb742b007 in g_closure_invoke () from /lib/libgobject-2.0.so.0
#5  0xb743cc58 in signal_emit_unlocked_R () from /lib/libgobject-2.0.so.0
#6  0xb7444fce in g_signal_emit_valist () from /lib/libgobject-2.0.so.0
#7  0xb74453e4 in g_signal_emit () from /lib/libgobject-2.0.so.0
#8  0xb7c27d73 in gtk_widget_event_internal () from /lib/libgtk-x11-2.0.so.0
#9  0xb7acfa4c in gtk_propagate_event () from /lib/libgtk-x11-2.0.so.0
#10 0xb7acfd20 in gtk_main_do_event () from /lib/libgtk-x11-2.0.so.0
#11 0xb78eec59 in gdk_event_dispatch () from /lib/libgdk-x11-2.0.so.0
#12 0xb733a12b in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#13 0xb733a4d0 in g_main_context_iterate.isra.22 () from /lib/libglib-2.0.so.0
#14 0xb733a933 in g_main_loop_run () from /lib/libglib-2.0.so.0
#15 0xb7acea40 in gtk_main () from /lib/libgtk-x11-2.0.so.0
#16 0x0805264b in main (argc=1, argv=0xbffff6e4) at pcmanfm.c:234
(gdb) q
A debugging session is active.

        Inferior 1 [process 20875] will be killed.

Quit anyway? (y or n) y