sudo gdb lightdm 24513
[sudo] password for tim: 
GNU gdb (Ubuntu/Linaro 7.4-2012.04-0ubuntu2.1) 7.4-2012.04
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
For bug reporting instructions, please see:
<http://bugs.launchpad.net/gdb-linaro/>...
Reading symbols from /usr/sbin/lightdm...(no debugging symbols found)...done.
Attaching to program: /usr/sbin/lightdm, process 24513
Reading symbols from /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
Reading symbols from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
Reading symbols from /lib/x86_64-linux-gnu/libglib-2.0.so.0...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libglib-2.0.so.0
Reading symbols from /usr/lib/x86_64-linux-gnu/libXdmcp.so.6...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libXdmcp.so.6
Reading symbols from /usr/lib/x86_64-linux-gnu/libxcb.so.1...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libxcb.so.1
Reading symbols from /lib/x86_64-linux-gnu/libpam.so.0...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libpam.so.0
Reading symbols from /lib/x86_64-linux-gnu/libpthread.so.0...(no debugging symbols found)...done.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7fcef960c700 (LWP 24520)]
[New Thread 0x7fcef9e0d700 (LWP 24516)]
Loaded symbols for /lib/x86_64-linux-gnu/libpthread.so.0
Reading symbols from /lib/x86_64-linux-gnu/libc.so.6...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libc.so.6
Reading symbols from /usr/lib/x86_64-linux-gnu/libgmodule-2.0.so.0...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libgmodule-2.0.so.0
Reading symbols from /lib/x86_64-linux-gnu/libz.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libz.so.1
Reading symbols from /lib/x86_64-linux-gnu/libselinux.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libselinux.so.1
Reading symbols from /lib/x86_64-linux-gnu/libresolv.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libresolv.so.2
Reading symbols from /usr/lib/x86_64-linux-gnu/libffi.so.6...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libffi.so.6
Reading symbols from /lib/x86_64-linux-gnu/libpcre.so.3...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libpcre.so.3
Reading symbols from /lib/x86_64-linux-gnu/librt.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/librt.so.1
Reading symbols from /usr/lib/x86_64-linux-gnu/libXau.so.6...(no debugging symbols found)...done.
Loaded symbols for /usr/lib/x86_64-linux-gnu/libXau.so.6
Reading symbols from /lib/x86_64-linux-gnu/libdl.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libdl.so.2
Reading symbols from /lib64/ld-linux-x86-64.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
Reading symbols from /lib/x86_64-linux-gnu/libnss_compat.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libnss_compat.so.2
Reading symbols from /lib/x86_64-linux-gnu/libnsl.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libnsl.so.1
Reading symbols from /lib/x86_64-linux-gnu/libnss_nis.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libnss_nis.so.2
Reading symbols from /lib/x86_64-linux-gnu/libnss_files.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libnss_files.so.2
0x00007fcefb9a0f03 in poll () from /lib/x86_64-linux-gnu/libc.so.6