root@penguin:~# gdb /usr/bin/Xorg
GNU gdb 6.6-debian
Copyright (C) 2006 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i486-linux-gnu"...
Using host libthread_db library "/lib/tls/i686/cmov/libthread_db.so.1".
(gdb)
[1]+  Stopped                 gdb /usr/bin/Xorg
root@penguin:~# pidof X
7260
root@penguin:~# fg
gdb /usr/bin/Xorg
attach 7260
Attaching to program: /usr/bin/Xorg, process 7260
Reading symbols from /lib/tls/i686/cmov/libdl.so.2...Reading symbols from /usr/.done.
Loaded symbols for /lib/tls/i686/cmov/libdl.so.2
Reading symbols from /usr/lib/libXfont.so.1...Reading symbols from /usr/lib/deb.done.
Loaded symbols for /usr/lib/libXfont.so.1
Reading symbols from /usr/lib/libXau.so.6...Reading symbols from /usr/lib/debug.done.
Loaded symbols for /usr/lib/libXau.so.6
Reading symbols from /usr/lib/libfontenc.so.1...done.
Loaded symbols for /usr/lib/libfontenc.so.1
Reading symbols from /usr/lib/libXdmcp.so.6...Reading symbols from /usr/lib/deb.done.
Loaded symbols for /usr/lib/libXdmcp.so.6
Reading symbols from /lib/tls/i686/cmov/libm.so.6...Reading symbols from /usr/l.done.
Loaded symbols for /lib/tls/i686/cmov/libm.so.6
Reading symbols from /lib/libgcc_s.so.1...done.
Loaded symbols for /lib/libgcc_s.so.1
Reading symbols from /lib/tls/i686/cmov/libc.so.6...Reading symbols from /usr/l.done.
Loaded symbols for /lib/tls/i686/cmov/libc.so.6
Reading symbols from /lib/ld-linux.so.2...Reading symbols from /usr/lib/debug/l.done.
Loaded symbols for /lib/ld-linux.so.2
Reading symbols from /usr/lib/libfreetype.so.6...done.
Loaded symbols for /usr/lib/libfreetype.so.6
Reading symbols from /usr/lib/libz.so.1...done.
Loaded symbols for /usr/lib/libz.so.1
Reading symbols from /usr/lib/xorg/modules/libpcidata.so...Reading symbols from.done.
Loaded symbols for /usr/lib/xorg/modules//libpcidata.so
Reading symbols from /usr/lib/xorg/modules/extensions/libdbe.so...Reading symbo.done.
Loaded symbols for /usr/lib/xorg/modules/extensions//libdbe.so
Reading symbols from /usr/lib/xorg/modules/extensions/libextmod.so...Reading sy.done.
Loaded symbols for /usr/lib/xorg/modules/extensions//libextmod.so
Reading symbols from /usr/lib/xorg/modules/linux/libfbdevhw.so...Reading symbol.done.
Loaded symbols for /usr/lib/xorg/modules/linux//libfbdevhw.so
Reading symbols from /usr/lib/xorg/modules/extensions/libglx.so...Reading symbo.done.
Loaded symbols for /usr/lib/xorg/modules/extensions//libglx.so
Reading symbols from /usr/lib/xorg/modules/extensions/librecord.so...Reading sy.done.
Loaded symbols for /usr/lib/xorg/modules/extensions//librecord.so
Reading symbols from /usr/lib/xorg/modules/extensions/libdri.so...Reading symbo.done.
Loaded symbols for /usr/lib/xorg/modules/extensions//libdri.so
Reading symbols from /usr/lib/libdrm.so.2...done.
Loaded symbols for /usr/lib/libdrm.so.2
Reading symbols from /usr/lib/xorg/modules/fonts/libfreetype.so...Reading symbo.done.
Loaded symbols for /usr/lib/xorg/modules//fonts/libfreetype.so
Reading symbols from /usr/lib/xorg/modules/libvbe.so...Reading symbols from /us.done.
Loaded symbols for /usr/lib/xorg/modules//libvbe.so
Reading symbols from /usr/lib/xorg/modules/drivers/radeon_drv.so...Reading symb.done.
Loaded symbols for /usr/lib/xorg/modules/drivers//radeon_drv.so
Reading symbols from /usr/lib/xorg/modules/drivers/ati_drv.so...Reading symbols.done.
Loaded symbols for /usr/lib/xorg/modules/drivers//ati_drv.so
Reading symbols from /usr/lib/xorg/modules/input/evdev_drv.so...done.
Loaded symbols for /usr/lib/xorg/modules/input//evdev_drv.so
Reading symbols from /usr/lib/xorg/modules/libvgahw.so...Reading symbols from /.done.
Loaded symbols for /usr/lib/xorg/modules//libvgahw.so
Reading symbols from /usr/lib/xorg/modules/libint10.so...Reading symbols from /.done.
Loaded symbols for /usr/lib/xorg/modules//libint10.so
Reading symbols from /usr/lib/xorg/modules/libfb.so...Reading symbols from /usr.done.
Loaded symbols for /usr/lib/xorg/modules//libfb.so
Reading symbols from /usr/lib/xorg/modules/libxaa.so...Reading symbols from /us.done.
Loaded symbols for /usr/lib/xorg/modules//libxaa.so
Reading symbols from /usr/lib/xorg/modules/multimedia/theatre_detect_drv.so...R.done.
Loaded symbols for /usr/lib/xorg/modules/multimedia//theatre_detect_drv.so
Reading symbols from /usr/lib/dri/r300_dri.so...done.
Loaded symbols for /usr/lib/dri/r300_dri.so
Reading symbols from /lib/tls/i686/cmov/libpthread.so.0...Reading symbols from .[Thread debugging using libthread_db enabled]
[New Thread -1211451728 (LWP 7260)]
done.
Loaded symbols for /lib/tls/i686/cmov/libpthread.so.0
Reading symbols from /usr/lib/libexpat.so.1...done.
Loaded symbols for /usr/lib/libexpat.so.1
0xffffe410 in __kernel_vsyscall ()
(gdb) bt
#0  0xffffe410 in __kernel_vsyscall ()
#1  0xb7dfd8b9 in ioctl () from /lib/tls/i686/cmov/libc.so.6
#2  0xb7bbaa8b in drmCommandWrite () from /usr/lib/libdrm.so.2
#3  0xa6e9dbb3 in ?? () from /usr/lib/dri/r300_dri.so
#4  0x00000008 in ?? ()
#5  0x00000017 in ?? ()
#6  0x08709494 in ?? ()
#7  0x00000004 in ?? ()
#8  0x084e78b8 in ?? ()
#9  0x001e8320 in ?? ()
#10 0x08709440 in ?? ()
#11 0x084e78b8 in ?? ()
#12 0x00000001 in ?? ()
#13 0x08447730 in ?? ()
#14 0xbf81ac58 in ?? ()
#15 0xa6ebfb50 in _mesa_Finish () from /usr/lib/dri/r300_dri.so
Backtrace stopped: frame did not save the PC
(gdb)