netifd: not bringing up tunnel interface with NO_DEVICE

Describe the bug

Randomly, changing some configuration parameters or creating a 6in4 or wireguard interface leads to netifd not being able to bring up the interface when running ifup, with ifstatus returning NO_DEVICE.

OpenWrt version

r23497-6637af95aa

OpenWrt release

23.05.0

OpenWrt target/subtarget

ramips/mt7621

Device

UniElec U7621-06 (16M flash)

Image kind

Official downloaded image

Steps to reproduce

Config:

config interface 'wan6'
        option proto '6in4'
        option peeraddr 'xxx.xxx.xxx.xxx'
        option ip6addr '2a0e:97c0:38f:fffd::1/64'
        list ip6prefix '2a0e:97c0:38f::/64'
        option ip6assign '64'
        option mtu '1472'
        option ipaddr 'yyy.yyy.yyy.yyy'
        option ttl '255'

Debug config in /etc/init.d/network:

start_service() {
        init_switch

        procd_open_instance
        procd_set_param command /sbin/netifd -l 5 -d 15
        procd_set_param stdout 1
        procd_set_param stderr 1
        procd_set_param respawn
        procd_set_param watch network.interface
        [ -e /proc/sys/kernel/core_pattern ] && {
                procd_set_param limits core="unlimited"
        }
        procd_close_instance
}

Logs (no errors or debug-level logs strangely):

Sun Feb 11 17:42:59 2024 daemon.err netifd[1493]: device_apply_config(1188): Device 'br-lan': config applied
Sun Feb 11 17:42:59 2024 daemon.err netifd[1493]: interface_update(1402): Update interface 'loopback'
Sun Feb 11 17:42:59 2024 daemon.err netifd[1493]: interface_update(1402): Update interface 'lan'
Sun Feb 11 17:42:59 2024 daemon.err netifd[1493]: interface_add_dns_server(1435): Add IPv4 DNS server: 192.168.69.1
Sun Feb 11 17:42:59 2024 daemon.err netifd[1493]: interface_update(1402): Update interface 'wan'
Sun Feb 11 17:42:59 2024 daemon.err netifd[1493]: interface_update(1402): Update interface 'wan6'
Sun Feb 11 17:42:59 2024 daemon.err netifd[1493]: interface_update(1402): Update interface 'wg_securebit'
Sun Feb 11 17:42:59 2024 daemon.err netifd[1493]: wdev_update(754): Update wireless device 'radio0'
Sun Feb 11 17:42:59 2024 daemon.err netifd[1493]: wdev_update(754): Update wireless device 'radio1'

Creating the interface through luci yields the same result.

Actual behaviour

Running ifup does not create the iface, with ifstatus returning NO_DEVICE.

Same thing happens when restarting the interface through luci, even across reboots.

Deleting and recreating the config of the same exact interface a few times fixes.

Expected behaviour

The interface gets created correctly.

Additional info

No response

Diffconfig

No response

Terms

• I am reporting an issue for OpenWrt, not an unsupported fork.

Start by reproducing the 6in4 configuration with the /etc/init.d/network debug settings, then run ifup and ifstatus while reviewing the netifd logs. Compare the behavior with a freshly recreated interface and trace the netifd entry points involved in tunnel creation; done means the configured tunnel is created reliably and no longer reports NO_DEVICE.