Comment 2 for bug 1062314

I think the issue here is that nova.virt.firewall.py IptablesFirewallDriver.instance_rules() is calling get_instance_nw_info() which is causing rpcs to be fired off _while_still_holding_the_iptables_lock. I suspect that the rpcs need to happen outside the lock.

From yet more instrumented code:

A synchronous RPC call is being made while a lock is held. This is probably a bug. Please report it. Include lines following this that start with ** please.
** multicall
** call
** call
** call
** get_instance_nw_info
** instance_rules
** add_filters_for_instance
** do_refresh_security_group_rules
** inner_while_holding_lock
** refresh_security_group_members
** refresh_security_group_members
** refresh_security_group_members
** wrapped
** _process_data
** wrapped
** _spawn_n_impl
** end of stack trace