packet storm as nics in STP enabled netns bridges lack BPDU maddr 01:80:c2:00:00:00

Bridges with STP enabled, only if in the non-default namespace, connecting the nic as a port to the bridge will not add the STP multicast address to the port nics, causing them to fail in all important BPDU topology updates. This leads to packet storms, effectively locking up all connected systems -- all the problems STP is designed to prevent.

This bug exists in ubuntu's 5.15 generic Jammy and 6.1 22.04c kernels. 100% reproducible. Below you'll see two cases that vary only in that one takes place in a non-default network namespace. The only material difference is the nic ports in the non-default namespace lack the STP bridge multicast address.

Notice in the default namespace, for example, we have:

 ip -d link show lan0bridge
31: lan0bridge: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 52:54:e5:79:c5:7a brd ff:ff:ff:ff:ff:ff promiscuity 0 minmtu 68 maxmtu 65535
    bridge forward_delay 1500 hello_time 200 max_age 2000 ageing_time 30000 stp_state 1 priority 28 vlan_filtering 0 vlan_protocol 802.1Q bridge_id 001c.52:54:e5:79:c5:7a designated_root 001c.52:54:e5:79:c5:7a root_port 1 root_path_cost 4 topology_change 0 topology_change_detected 0 hello_timer 0.00 tcn_timer 0.00 topology_change_timer 0.00 gc_timer 24.87 vlan_default_pvid 1 vlan_stats_enabled 0 vlan_stats_per_port 0 group_fwd_mask 0 group_address 01:80:c2:00:00:00 mcast_snooping 1 mcast_router 1 mcast_query_use_ifaddr 0 mcast_querier 0 mcast_hash_elasticity 16 mcast_hash_max 4096 mcast_last_member_count 2 mcast_startup_query_count 2 mcast_last_member_interval 100 mcast_membership_interval 26000 mcast_querier_interval 25500 mcast_query_interval 12500 mcast_query_response_interval 1000 mcast_startup_query_interval 3124 mcast_stats_enabled 0 mcast_igmp_version 2 mcast_mld_version 1 nf_call_iptables 0 nf_call_ip6tables 0 nf_call_arptables 0 addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535

And an example port:

ip -d addr show gnv0lan1
32: gnv0lan1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master lan0bridge state UNKNOWN group default qlen 1000
    link/ether 52:54:86:cb:d4:05 brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 65485
    geneve id 7745 remote 192.XXX.XXX.XXx ttl auto dstport 6081 noudpcsum udp6zerocsumrx
    bridge_slave state forwarding priority 32 cost 100 hairpin off guard off root_block off fastleave off learning on flood on port_id 0x8002 port_no 0x2 designated_port 32770 designated_cost 4 designated_bridge 001c.52:54:e5:79:c5:7a designated_root 0014.52:54:ff:79:8b:4d hold_timer 0.68 message_age_timer 0.00 forward_delay_timer 0.00 topology_change_ack 0 config_pending 0 proxy_arp off proxy_arp_wifi off mcast_router 1 mcast_fast_leave off mcast_flood on mcast_to_unicast off neigh_suppress off group_fwd_mask 0 group_fwd_mask_str 0x0 vlan_tunnel off isolated off numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535

And the expected
# ip maddr show gnv0lan1
32: gnv0lan1
        link 33:33:00:00:00:02 users 2
        link 01:00:5e:00:00:01
        link 33:33:00:00:00:01
        link 01:80:c2:00:00:00 <-- STP multicast address.
...

But in a non-default namespace we have, for example:

root@rssnoc2e0:~# ip netns exec squad0ns ip -d link show sqd0lanbr
20: sqd0lanbr: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1370 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 2a:19:e7:b2:98:c6 brd ff:ff:ff:ff:ff:ff promiscuity 0 minmtu 68 maxmtu 65535
    bridge forward_delay 1500 hello_time 200 max_age 2000 ageing_time 30000 stp_state 1 priority 10000 vlan_filtering 0 vlan_protocol 802.1Q bridge_id 2710.2a:19:e7:b2:98:c6 designated_root 2710.2a:19:e7:b2:98:c6 root_port 0 root_path_cost 0 topology_change 0 topology_change_detected 0 hello_timer 0.05 tcn_timer 0.00 topology_change_timer 0.00 gc_timer 0.00 vlan_default_pvid 1 vlan_stats_enabled 0 vlan_stats_per_port 0 group_fwd_mask 0 group_address 01:80:c2:00:00:00 mcast_snooping 1 mcast_router 1 mcast_query_use_ifaddr 0 mcast_querier 0 mcast_hash_elasticity 16 mcast_hash_max 4096 mcast_last_member_count 2 mcast_startup_query_count 2 mcast_last_member_interval 100 mcast_membership_interval 26000 mcast_querier_interval 25500 mcast_query_interval 12500 mcast_query_response_interval 1000 mcast_startup_query_interval 3124 mcast_stats_enabled 0 mcast_igmp_version 2 mcast_mld_version 1 nf_call_iptables 0 nf_call_ip6tables 0 nf_call_arptables 0 addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535

And a nic on that bridge:

root@rssnoc2e0:~# ip netns exec squad0ns ip -d link show gnv1lan
21: gnv1lan: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1370 qdisc noqueue master sqd0lanbr state UNKNOWN mode DEFAULT group default qlen 1000
    link/ether 4a:cf:01:4b:0a:fd brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 65485
    geneve id 7745 remote 192.XXX.XXX.XXX ttl auto dstport 6081 noudpcsum udp6zerocsumrx
    bridge_slave state forwarding priority 32 cost 2048 hairpin off guard off root_block off fastleave off learning on flood on port_id 0x8001 port_no 0x1 designated_port 32769 designated_cost 0 designated_bridge 2710.2a:19:e7:b2:98:c6 designated_root 2710.2a:19:e7:b2:98:c6 hold_timer 0.70 message_age_timer 0.00 forward_delay_timer 0.00 topology_change_ack 0 config_pending 0 proxy_arp off proxy_arp_wifi off mcast_router 1 mcast_fast_leave off mcast_flood on mcast_to_unicast off neigh_suppress off group_fwd_mask 0 group_fwd_mask_str 0x0 vlan_tunnel off isolated off addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535

And here, we see the STP multicast address is missing:
root@rssnoc2e0:~# ip netns exec squad0ns ip maddr show gnv1lan
21: gnv1lan
        link 33:33:00:00:00:01
        link 01:00:5e:00:00:01
        inet 224.0.0.1
        inet6 ff02::1
        inet6 ff01::1
root@rssnoc2e0:~#

!! Missing multicast address for STP BPDU reception.