Comment 3 for bug 498855

Just to add to this:

I tried running firefox --debug and there are no errors within GDB and it gets this far:

matt@matt-desktop:~$ firefox --debug
/usr/bin/gdb /usr/lib/firefox-3.5.6/firefox -x /tmp/mozargs.okUqHw
GNU gdb (GDB) 7.0-ubuntu
Copyright (C) 2009 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://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/lib/firefox-3.5.6/firefox...(no debugging symbols found)...done.
(gdb) run
Starting program: /usr/lib/firefox-3.5.6/firefox
[Thread debugging using libthread_db enabled]

In system monitor it says that the waiting channel is "futex_wait_queue_me"