Comment 2 for bug 794096

The dmesg output in the bug description comes from log setup from firestarter (/etc/firestarter/firewall), I suspect that some of the rules are triggering the bug (as you also noted on irc discussion). But I tried to install firestarter and was unable to reproduce the issue, so can be something specific or configuration I don't have.

Even if you don't run firestart, just keeping it installed will make it start and add some rules, it could also conflict with other services (happened here, it removed/changed nat rules that were previously setup by libvirt for my vms)

Between the reported working (2.6.38-8.42) and non-working (2.6.38-10-generic) kernel, we have the following netfilter changes:
44ff155 netfilter: ipt_CLUSTERIP: fix buffer overflow
2444a5d netfilter: arp_tables: fix infoleak to userspace
ec6128c netfilter: xtables: fix reentrancy
43bfce2 netfilter: ip_tables: fix infoleak to userspace

Probably the ip_tables one can be causing issues here, I'll build test kernels with each one reverted and ask for testing soon.