When updated router info comes in to firewall_l3_agent_v2.py without the _interfaces field set, the code does not gracefully detect this and skip the update. This was picked up in tempest testing after the RC cutoff. The fix for master is under review; the fix needs to be backported to stable/neutron. Fix in master is: https://review.openstack.org/#/c/371611
I found an example of an updated router that does not have _interfaces as an attribute at [1]:
2016-09-15 19:37:08.356 21040 ERROR neutron_fwaas.services.firewall.agents.l3reference.firewall_l3_agent_v2 [req-b3e3ccbc-92ea-4c8e-8196-2987ecdd0195 - -] FWaaS router update RPC info call failed for {u'enable_snat': True, u'gw_port': {u'allowed_address_pairs': [], u'extra_dhcp_opts': [], u'updated_at': u'2016-09-15T19:36:31', u'device_owner': u'network:router_gateway', u'revision_number': 7, u'port_security_enabled': False, u'binding:profile': {}, u'binding:vnic_type': u'normal', u'fixed_ips': [{u'subnet_id': u'b27366c2-987c-4f6c-85a6-4fa329392ade', u'prefixlen': 24, u'ip_address': u'172.24.5.11'}, {u'subnet_id': u'71583438-8240-4bc1-a12f-3fc28087dff3', u'prefixlen': 64, u'ip_address': u'2001:db8::6'}], u'id': u'38a74555-f603-4287-9667-c13a7bcb8779', u'security_groups': [], u'binding:vif_details': {u'port_filter': True, u'ovs_hybrid_plug': True}, u'address_scopes': {u'4': None, u'6': None}, u'binding:vif_type': u'ovs', u'mac_address': u'fa:16:3e:5f:69:e7', u'project_id': u'', u'status': u'ACTIVE', u'subnets': [{u'dns_nameservers': [], u'ipv6_ra_mode': None, u'gateway_ip': u'2001:db8::2', u'cidr': u'2001:db8::/64', u'id': u'71583438-8240-4bc1-a12f-3fc28087dff3', u'subnetpool_id': None}, {u'dns_nameservers': [], u'ipv6_ra_mode': None, u'gateway_ip': u'172.24.5.1', u'cidr': u'172.24.5.0/24', u'id': u'b27366c2-987c-4f6c-85a6-4fa329392ade', u'subnetpool_id': None}], u'binding:host_id': u'ubuntu-trusty-rax-ord-4320605', u'description': u'', u'device_id': u'bcb45377-b7b2-4186-98dd-58e77a9b75e3', u'name': u'', u'admin_state_up': True, u'network_id': u'16004da0-37c9-4481-b769-0706b581d9e9', u'tenant_id': u'', u'created_at': u'2016-09-15T19:36:29', u'mtu': 1500, u'extra_subnets': []}, u'updated_at': u'2016-09-15T19:37:07', u'revision_number': 7, u'id': u'bcb45377-b7b2-4186-98dd-58e77a9b75e3', u'availability_zone_hints': [], u'availability_zones': [u'nova'], u'distributed': False, u'project_id': u'750d1d0452334b93815857b6b9bc9190', u'status': u'ACTIVE', u'ha_vr_id': 0, u'description': u'', u'ha': False, u'gw_port_host': u'ubuntu-trusty-rax-ord-4320605', u'external_gateway_info': {u'network_id': u'16004da0-37c9-4481-b769-0706b581d9e9', u'enable_snat': True, u'external_fixed_ips': [{u'subnet_id': u'b27366c2-987c-4f6c-85a6-4fa329392ade', u'ip_address': u'172.24.5.11'}, {u'subnet_id': u'71583438-8240-4bc1-a12f-3fc28087dff3', u'ip_address': u'2001:db8::6'}]}, u'name': u'tempest-router-smoke-1843134667', u'gw_port_id': u'38a74555-f603-4287-9667-c13a7bcb8779', u'admin_state_up': True, u'tenant_id': u'750d1d0452334b93815857b6b9bc9190', u'created_at': u'2016-09-15T19:36:28', u'flavor_id': None, u'routes': []}
[1] http://logs.openstack.org/74/370274/11/check/gate-neutron-fwaas-dsvm-tempest/0768c92/logs/screen-q-l3.txt.gz#_2016-09-15_19_37_08_356
An example of tempest triggering this issue: http://