Hostapd: VLAN: br_delif: Failure determining interface

After reading https://openwrt.org/docs/guide-user/network/wifi/wireless.security.8021x I cleaned up my network config, removing a lot of static entries that are dynamically assigned by hostapd. This finally got rid of some daemon.err hostapd: VLAN: errors caused by bridge devices and interfaces existing in our network configuation prior to hostapd dynamic configuration trying to operate on them.

We got them all cleaned, but there still exists one, so we believe maybe there is still some smally syntax errors in how our interfaces are defined.

Below shows the cleaned up logs from a host connecting to wlan0 and being dynamically bridged to br-vlan71. When all hosts on a VLAN are disconnected, hostapd removes the wifi vlan interface from the dynamic bridge.

We still see this one error

daemon.err hostapd: VLAN: br_delif: Failure determining interface index for 'wlan0.71'

Is there any way to get rid of this error in the logs? Or is this just something that can not be resolved due to wifi drivers. I tried creating an interface that references device wlan0.71 with no success.

Everything works, we just want to get rid of errors in the logs, that might otherwise indicate a functional issue.

Fri Jan 20 22:46:22 2023 daemon.notice hostapd: wlan0: AP-ENABLED
Fri Jan 20 22:49:43 2023 daemon.info hostapd: wlan0: STA 58:6d:8f:ed:38:22 RADIUS: VLAN ID 71
Fri Jan 20 22:49:43 2023 kern.info kernel: [  993.490346] br-vlan71: port 1(vlan71) entered blocking state
Fri Jan 20 22:49:43 2023 kern.info kernel: [  993.496176] br-vlan71: port 1(vlan71) entered disabled state
Fri Jan 20 22:49:43 2023 kern.info kernel: [  993.502188] device vlan71 entered promiscuous mode
Fri Jan 20 22:49:43 2023 kern.info kernel: [  993.523846] device eth0 entered promiscuous mode
Fri Jan 20 22:49:43 2023 kern.info kernel: [  993.528883] br-vlan71: port 1(vlan71) entered blocking state
Fri Jan 20 22:49:43 2023 kern.info kernel: [  993.534682] br-vlan71: port 1(vlan71) entered forwarding state
Fri Jan 20 22:49:43 2023 kern.info kernel: [  993.564577] br-vlan71: port 2(wlan0.71) entered blocking state
Fri Jan 20 22:49:43 2023 kern.info kernel: [  993.570682] br-vlan71: port 2(wlan0.71) entered disabled state
Fri Jan 20 22:49:43 2023 kern.info kernel: [  993.576987] device wlan0.71 entered promiscuous mode
Fri Jan 20 22:49:43 2023 kern.info kernel: [  993.582309] br-vlan71: port 2(wlan0.71) entered blocking state
Fri Jan 20 22:49:43 2023 kern.info kernel: [  993.588293] br-vlan71: port 2(wlan0.71) entered forwarding state
Fri Jan 20 22:49:43 2023 daemon.info hostapd: wlan0: STA 58:6d:8f:ed:38:22 IEEE 802.11: authenticated
Fri Jan 20 22:49:43 2023 daemon.info hostapd: wlan0: STA 58:6d:8f:ed:38:22 IEEE 802.11: associated (aid 1)
Fri Jan 20 22:49:43 2023 daemon.notice hostapd: wlan0: AP-STA-CONNECTED 58:6d:8f:ed:38:22
Fri Jan 20 22:49:43 2023 daemon.info hostapd: wlan0: STA 58:6d:8f:ed:38:22 RADIUS: starting accounting session 05AFF118C9E62807
Fri Jan 20 22:50:16 2023 daemon.notice hostapd: wlan0: AP-STA-DISCONNECTED 58:6d:8f:ed:38:22
Fri Jan 20 22:50:16 2023 daemon.info hostapd: wlan0: STA 58:6d:8f:ed:38:22 RADIUS: stopped accounting session 05AFF118C9E62807
Fri Jan 20 22:50:16 2023 kern.info kernel: [ 1027.034715] br-vlan71: port 2(wlan0.71) entered disabled state
Fri Jan 20 22:50:16 2023 kern.info kernel: [ 1027.042381] device wlan0.71 left promiscuous mode
Fri Jan 20 22:50:16 2023 kern.info kernel: [ 1027.047250] br-vlan71: port 2(wlan0.71) entered disabled state
Fri Jan 20 22:50:16 2023 daemon.err hostapd: VLAN: br_delif: Failure determining interface index for 'wlan0.71'
Fri Jan 20 22:50:16 2023 kern.info kernel: [ 1027.167568] device vlan71 left promiscuous mode
Fri Jan 20 22:50:16 2023 kern.info kernel: [ 1027.172250] device eth0 left promiscuous mode
Fri Jan 20 22:50:16 2023 kern.info kernel: [ 1027.177017] br-vlan71: port 1(vlan71) entered disabled state

I had a closer look at when devices are being added and removed by hostapd, and it seems that when devices are connected, there is indeed an interface index for wlan0.71 as shown in ip link show.

133: wlan0.71: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br-vlan71 state UNKNOWN qlen 1000
link/ether 60:e3:27:a4:66:89 brd ff:ff:ff:ff:ff:ff

And immediately after the last client disconnects, the interface is removed and cleaned up, so it seems something is just beating hostapd to this, and when the hostapd dynamic cleanup of removing the interface from the bridge, before removing the bridge, is likely the result of the wireless driver

Unless somebody else has some insight, I am just going to ignore these messages and assume it is just a wireless + bridge scenario not handled by hostapd