Bug#498627: Found a patch that solves the issue

[Pavel Fertser <fercerpav@gmail.com>]

After applying a patch from http://lkml.org/lkml/2008/8/17/215 to the
vanilla kernel i don't get oopses anymore.

To successfully use mount.cifs with kerberos, however, i needed to install
keyutils and to add the following lines to /etc/request-key.conf (should a
dependency be added to smbfs?):
create      cifs.spnego    * * /usr/sbin/cifs.upcall -c %k
create      dns_resolver   * * /usr/sbin/cifs.upcall %k

Also it occured that my default realm was incomplete (i.e. WORK instead of
WORK.LOCAL). After the change to /etc/krb5.conf i was able to successfully
mount the share.

Hope this helps.
Happy hacking! :)