I just experienced this bug on Ubuntu Dapper. While searching, I came across these similar sounding bugs for Red Hat: https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=204791 and CentOS: http://bugs.centos.org/view.php?id=1634 -- LVM Snapshot removal causes intermittent kernel panic https://launchpad.net/bugs/71567