[Abandoned] Wakeup from suspend: NM botches re-activation of bridge

-thc · 2025-11-26 13:05:33

While moving from VirtualBox to QEMU/KVM I stumbled upon a curious behavior of NetworkManager regarding my main bridge.

The bridge (id: "Bridge") is set up with my Ethernet adapter as a member (id: "Ethernet slave") and cloning the MAC addresses such a way that the bridge has the original MAC address ("48:21:0B:MM:MM:MM") of the Ethernet adapter and the latter an artificial one ("48:21:0B:NN:NN:NN").

As long as the box is not suspended everything works as expected - which the boot log confirms:

Nov 26 06:41:24 box systemd[1]: Reached target Preparation for Network.
Nov 26 06:41:24 box systemd[1]: Starting Network Manager...
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6009] NetworkManager (version 1.54.2-1) is starting... (boot:b508666c-6f61-4abf-a66b-ee18b2bf188e)
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6010] Read config: /etc/NetworkManager/NetworkManager.conf, /usr/lib/NetworkManager/conf.d/20-connectivity.conf, /etc/NetworkManager/conf.d/{connectivity.conf,dns.conf,unmanaged.conf}
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6079] manager[0x55dd0eb3c8a0]: monitoring kernel firmware directory '/lib/firmware'.
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6095] hostname: hostname: using hostnamed
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6096] hostname: static hostname changed from (none) to "box"
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6101] dns-mgr: init: dns=systemd-resolved rc-manager=symlink, plugin=systemd-resolved
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6125] rfkill1: found Wi-Fi radio killswitch (at /sys/devices/pci0000:00/0000:00:14.3/ieee80211/phy0/rfkill1) (driver iwlwifi)
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6128] manager[0x55dd0eb3c8a0]: rfkill: Wi-Fi hardware radio set disabled
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6128] manager[0x55dd0eb3c8a0]: rfkill: WWAN hardware radio set enabled
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6156] Loaded device plugin: NMAtmManager (/usr/lib/NetworkManager/1.54.2-1/libnm-device-plugin-adsl.so)
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6163] Loaded device plugin: NMOvsFactory (/usr/lib/NetworkManager/1.54.2-1/libnm-device-plugin-ovs.so)
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6169] Loaded device plugin: NMWifiFactory (/usr/lib/NetworkManager/1.54.2-1/libnm-device-plugin-wifi.so)
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6321] Loaded device plugin: NMTeamFactory (/usr/lib/NetworkManager/1.54.2-1/libnm-device-plugin-team.so)
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6342] Loaded device plugin: NMBluezManager (/usr/lib/NetworkManager/1.54.2-1/libnm-device-plugin-bluetooth.so)
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6345] Loaded device plugin: NMWwanFactory (/usr/lib/NetworkManager/1.54.2-1/libnm-device-plugin-wwan.so)
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6347] manager: rfkill: Wi-Fi disabled by radio killswitch; disabled by state file
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6348] manager: rfkill: WWAN enabled by radio killswitch; enabled by state file
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6348] manager: Networking is enabled by state file
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6350] settings: Loaded settings plugin: keyfile (internal)
Nov 26 06:41:24 box systemd[1]: Starting Network Manager Script Dispatcher Service...
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6428] dhcp: init: Using DHCP client 'internal'
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6430] manager: (lo): new Loopback device (/org/freedesktop/NetworkManager/Devices/1)
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6435] device (lo): state change: unmanaged -> unavailable (reason 'connection-assumed', managed-type: 'external')
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6438] device (lo): state change: unavailable -> disconnected (reason 'connection-assumed', managed-type: 'external')
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6442] device (lo): Activation: starting connection 'lo' (044c8111-8d88-4e9d-893e-ef261010e7d3)
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6449] manager: (enp100s0): new Ethernet device (/org/freedesktop/NetworkManager/Devices/2)
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6450] device (enp100s0): state change: unmanaged -> unavailable (reason 'managed', managed-type: 'external')
Nov 26 06:41:24 box systemd[1]: Started Network Manager Script Dispatcher Service.
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6607] device (wlo1): driver supports Access Point (AP) mode
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6611] manager: (wlo1): new 802.11 Wi-Fi device (/org/freedesktop/NetworkManager/Devices/3)
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6617] manager: (bridge0): new Bridge device (/org/freedesktop/NetworkManager/Devices/4)
Nov 26 06:41:24 box kernel: bridge: filtering via arp/ip/ip6tables is no longer available by default. Update your scripts to load br_netfilter if you need this.
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6796] device (bridge0): state change: unmanaged -> unavailable (reason 'managed', managed-type: 'external')
Nov 26 06:41:24 box systemd[1]: Started Network Manager.
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6810] bus-manager: acquired D-Bus service "org.freedesktop.NetworkManager"
Nov 26 06:41:24 box systemd[1]: Reached target Network.
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6822] ovsdb: disconnected from ovsdb
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6823] device (lo): state change: disconnected -> prepare (reason 'none', managed-type: 'external')
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6825] device (lo): state change: prepare -> config (reason 'none', managed-type: 'external')
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6826] device (lo): state change: config -> ip-config (reason 'none', managed-type: 'external')
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6829] device (lo): state change: ip-config -> ip-check (reason 'none', managed-type: 'external')
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6835] device (bridge0): state change: unavailable -> disconnected (reason 'none', managed-type: 'full')
Nov 26 06:41:24 box systemd[1]: Starting CUPS Scheduler...
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6840] policy: auto-activating connection 'Bridge' (be3f4a45-174c-4228-8604-44131fb9ec89)
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6844] device (lo): state change: ip-check -> secondaries (reason 'none', managed-type: 'external')
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6846] device (bridge0): Activation: starting connection 'Bridge' (be3f4a45-174c-4228-8604-44131fb9ec89)
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6846] device (lo): state change: secondaries -> activated (reason 'none', managed-type: 'external')
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6849] device (lo): Activation: successful, device activated.
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6853] device (bridge0): state change: disconnected -> prepare (reason 'none', managed-type: 'full')
Nov 26 06:41:24 box systemd[1]: Starting Permit User Sessions...
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6854] manager: NetworkManager state is now CONNECTING
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6859] device (bridge0): state change: prepare -> config (reason 'none', managed-type: 'full')
Nov 26 06:41:24 box NetworkManager[580]: <info>  [1764135684.6862] device (bridge0): state change: config -> ip-config (reason 'none', managed-type: 'full')
Nov 26 06:41:24 box systemd-resolved[375]: bridge0: Bus client set default route setting: no
Nov 26 06:41:24 box systemd-resolved[375]: bridge0: Bus client set DNSOverTLS setting: yes
Nov 26 06:41:27 box kernel: igc 0000:64:00.0 enp100s0: NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX/TX
Nov 26 06:41:27 box NetworkManager[580]: <info>  [1764135687.3805] device (enp100s0): carrier: link connected
Nov 26 06:41:27 box NetworkManager[580]: <info>  [1764135687.3810] device (enp100s0): state change: unavailable -> disconnected (reason 'carrier-changed', managed-type: 'full')
Nov 26 06:41:27 box NetworkManager[580]: <info>  [1764135687.3818] policy: auto-activating connection 'Ethernet slave' (f00d1efd-dc2b-4377-8d6f-50d8ae5e9dc9)
Nov 26 06:41:27 box NetworkManager[580]: <info>  [1764135687.3821] device (enp100s0): Activation: starting connection 'Ethernet slave' (f00d1efd-dc2b-4377-8d6f-50d8ae5e9dc9)
Nov 26 06:41:27 box NetworkManager[580]: <info>  [1764135687.3822] device (enp100s0): state change: disconnected -> prepare (reason 'none', managed-type: 'full')
Nov 26 06:41:27 box NetworkManager[580]: <info>  [1764135687.3830] device (enp100s0): set-hw-addr: set-cloned MAC address to 48:21:0B:NN:NN:NN (48:21:0B:NN:NN:NN)
Nov 26 06:41:27 box NetworkManager[580]: <info>  [1764135687.4311] device (enp100s0): state change: prepare -> config (reason 'none', managed-type: 'full')
Nov 26 06:41:27 box NetworkManager[580]: <info>  [1764135687.4322] device (enp100s0): state change: config -> ip-config (reason 'none', managed-type: 'full')
Nov 26 06:41:27 box NetworkManager[580]: <info>  [1764135687.4325] device (bridge0): attached bridge port enp100s0
Nov 26 06:41:27 box NetworkManager[580]: <info>  [1764135687.4325] device (enp100s0): Activation: connection 'Ethernet slave' attached as port, continuing activation
Nov 26 06:41:27 box NetworkManager[580]: <info>  [1764135687.4327] device (enp100s0): state change: ip-config -> ip-check (reason 'none', managed-type: 'full')
Nov 26 06:41:27 box kernel: bridge0: port 1(enp100s0) entered blocking state
Nov 26 06:41:27 box kernel: bridge0: port 1(enp100s0) entered disabled state
Nov 26 06:41:27 box kernel: igc 0000:64:00.0 enp100s0: entered allmulticast mode
Nov 26 06:41:27 box kernel: igc 0000:64:00.0 enp100s0: entered promiscuous mode
Nov 26 06:41:27 box NetworkManager[580]: <info>  [1764135687.4338] device (enp100s0): state change: ip-check -> secondaries (reason 'none', managed-type: 'full')
Nov 26 06:41:27 box NetworkManager[580]: <info>  [1764135687.4339] device (enp100s0): state change: secondaries -> activated (reason 'none', managed-type: 'full')
Nov 26 06:41:27 box NetworkManager[580]: <info>  [1764135687.4342] device (enp100s0): Activation: successful, device activated.
Nov 26 06:41:28 box systemd[1]: systemd-rfkill.service: Deactivated successfully.
Nov 26 06:41:30 box kernel: igc 0000:64:00.0 enp100s0: NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX/TX
Nov 26 06:41:30 box kernel: bridge0: port 1(enp100s0) entered blocking state
Nov 26 06:41:30 box kernel: bridge0: port 1(enp100s0) entered forwarding state
Nov 26 06:41:30 box NetworkManager[580]: <info>  [1764135690.9567] device (enp100s0): carrier: link connected
Nov 26 06:41:30 box NetworkManager[580]: <info>  [1764135690.9573] device (bridge0): carrier: link connected
Nov 26 06:41:30 box NetworkManager[580]: <info>  [1764135690.9577] dhcp4 (bridge0): activation: beginning transaction (timeout in 45 seconds)
Nov 26 06:41:30 box NetworkManager[580]: <info>  [1764135690.9701] dhcp4 (bridge0): state changed new lease, address=192.168.X.Y, acd pending
Nov 26 06:41:31 box NetworkManager[580]: <info>  [1764135691.0925] dhcp4 (bridge0): state changed new lease, address=192.168.X.Y
Nov 26 06:41:31 box NetworkManager[580]: <info>  [1764135691.0943] policy: set 'Bridge' (bridge0) as default for IPv4 routing and DNS
Nov 26 06:41:31 box systemd-resolved[375]: bridge0: Bus client set search domain list to: domain.home
Nov 26 06:41:31 box systemd-resolved[375]: bridge0: Bus client set default route setting: yes
Nov 26 06:41:31 box systemd-resolved[375]: bridge0: Bus client set DNS server list to: 192.168.X.Z
Nov 26 06:41:31 box NetworkManager[580]: <info>  [1764135691.1188] device (bridge0): state change: ip-config -> ip-check (reason 'none', managed-type: 'full')
Nov 26 06:41:31 box NetworkManager[580]: <info>  [1764135691.1220] device (bridge0): state change: ip-check -> secondaries (reason 'none', managed-type: 'full')
Nov 26 06:41:31 box NetworkManager[580]: <info>  [1764135691.1223] device (bridge0): state change: secondaries -> activated (reason 'none', managed-type: 'full')
Nov 26 06:41:31 box NetworkManager[580]: <info>  [1764135691.1226] manager: NetworkManager state is now CONNECTED_SITE
Nov 26 06:41:31 box NetworkManager[580]: <info>  [1764135691.1229] device (bridge0): Activation: successful, device activated.
Nov 26 06:41:31 box NetworkManager[580]: <info>  [1764135691.1234] manager: NetworkManager state is now CONNECTED_GLOBAL
Nov 26 06:41:31 box NetworkManager[580]: <info>  [1764135691.1237] manager: startup complete
Nov 26 06:41:32 box NetworkManager[580]: <info>  [1764135692.6523] dhcp6 (bridge0): activation: beginning transaction (timeout in 45 seconds)
Nov 26 06:41:32 box NetworkManager[580]: <info>  [1764135692.6547] policy: set 'Bridge' (bridge0) as default for IPv6 routing and DNS
Nov 26 06:41:32 box NetworkManager[580]: <info>  [1764135692.6555] dhcp6 (bridge0): state changed new lease
Nov 26 06:41:32 box systemd-resolved[375]: bridge0: Bus client set DNS server list to: 192.168.X.Z, fdXX:XXXX:XXXX:XXXX:YYYY:YYYY:YYYY:YYYY
Nov 26 06:41:32 box systemd[1]: Starting Network Manager Wait Online...
Nov 26 06:41:32 box systemd[1]: Finished Network Manager Wait Online.
Nov 26 06:41:32 box systemd[1]: Reached target Network is Online.

If the box is put to sleep (S3)

Nov 26 09:08:55 box NetworkManager[580]: <info>  [1764144535.1597] manager: sleep: sleep requested (sleeping: no  enabled: yes)
Nov 26 09:08:55 box NetworkManager[580]: <info>  [1764144535.1600] manager: NetworkManager state is now DISABLED (ASLEEP)

and subsequently woken up, NM acts strange:

Nov 26 09:13:47 box kernel: PM: suspend exit
Nov 26 09:13:47 box systemd[1]: Stopped target Suspend.
Nov 26 09:13:47 box systemd-resolved[375]: Closing all remaining TCP connections.
Nov 26 09:13:47 box systemd-resolved[375]: Resetting learnt feature levels on all servers.
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.3398] manager: sleep: wake requested (sleeping: yes  enabled: yes)
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.3399] device (enp100s0): state change: activated -> unmanaged (reason 'unmanaged-nm-disabled', managed-type: 'full')
Nov 26 09:13:47 box kernel: bridge0: port 1(enp100s0) entered disabled state
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.3895] device (enp100s0): set-hw-addr: reset MAC address to 48:21:0B:MM:MM:MM (unmanage)
Nov 26 09:13:47 box kernel: bridge0: port 1(enp100s0) entered disabled state
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4399] manager: NetworkManager state is now CONNECTED_GLOBAL
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4401] device (bridge0): bridge port enp100s0 was detached
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4401] device (enp100s0): released from controller device bridge0
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4406] device (enp100s0): state change: unmanaged -> unavailable (reason 'managed', managed-type: 'external')
Nov 26 09:13:47 box systemd[1]: Starting Network Manager Script Dispatcher Service...
Nov 26 09:13:47 box systemd[1]: Started Network Manager Script Dispatcher Service.
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4765] device (bridge0): ip:dhcp4: restarting
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4766] dhcp4 (bridge0): canceled DHCP transaction
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4766] dhcp4 (bridge0): activation: beginning transaction (timeout in 45 seconds)
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4766] dhcp4 (bridge0): state changed no lease
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4766] dhcp4 (bridge0): activation: beginning transaction (timeout in 45 seconds)
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4766] device (bridge0): ip:dhcp6: restarting
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4766] dhcp6 (bridge0): canceled DHCP transaction
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4766] dhcp6 (bridge0): activation: beginning transaction (timeout in 45 seconds)
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4766] dhcp6 (bridge0): state changed no lease
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4767] dhcp6 (bridge0): activation: beginning transaction (timeout in 45 seconds)
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4773] device (enp100s0): state change: unavailable -> disconnected (reason 'connection-assumed', managed-type: 'external')
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4775] device (enp100s0): Activation: starting connection 'enp100s0' (1eb1e0f4-fbbf-4d34-85d0-eaa2584c5fea)
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4776] device (enp100s0): state change: disconnected -> prepare (reason 'none', managed-type: 'external')
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4776] device (enp100s0): state change: prepare -> config (reason 'none', managed-type: 'external')
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4777] device (enp100s0): state change: config -> ip-config (reason 'none', managed-type: 'external')
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4777] device (bridge0): bridge port enp100s0 was attached
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4777] device (enp100s0): Activation: connection 'enp100s0' attached as port, continuing activation
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4778] device (enp100s0): state change: ip-config -> ip-check (reason 'none', managed-type: 'external')
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4909] device (enp100s0): state change: ip-check -> secondaries (reason 'none', managed-type: 'external')
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4910] device (enp100s0): state change: secondaries -> activated (reason 'none', managed-type: 'external')
Nov 26 09:13:47 box NetworkManager[580]: <info>  [1764144827.4912] device (enp100s0): Activation: successful, device activated.
Nov 26 09:13:50 box kernel: igc 0000:64:00.0 enp100s0: NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX/TX
Nov 26 09:13:50 box kernel: bridge0: port 1(enp100s0) entered blocking state
Nov 26 09:13:50 box kernel: bridge0: port 1(enp100s0) entered forwarding state
Nov 26 09:13:50 box NetworkManager[580]: <info>  [1764144830.1782] device (enp100s0): carrier: link connected
Nov 26 09:13:50 box NetworkManager[580]: <info>  [1764144830.1788] device (bridge0): carrier: link connected
Nov 26 09:13:50 box NetworkManager[580]: <info>  [1764144830.1790] device (bridge0): ip:dhcp4: restarting
Nov 26 09:13:50 box NetworkManager[580]: <info>  [1764144830.1925] dhcp4 (bridge0): canceled DHCP transaction
Nov 26 09:13:50 box NetworkManager[580]: <info>  [1764144830.1926] dhcp4 (bridge0): state changed no lease
Nov 26 09:13:50 box NetworkManager[580]: <info>  [1764144830.1927] dhcp4 (bridge0): activation: beginning transaction (timeout in 45 seconds)
Nov 26 09:13:50 box NetworkManager[580]: <info>  [1764144830.1930] device (bridge0): ip:dhcp6: restarting
Nov 26 09:13:50 box NetworkManager[580]: <info>  [1764144830.1930] dhcp6 (bridge0): canceled DHCP transaction
Nov 26 09:13:50 box NetworkManager[580]: <info>  [1764144830.1930] dhcp6 (bridge0): state changed no lease
Nov 26 09:13:50 box NetworkManager[580]: <info>  [1764144830.1931] dhcp6 (bridge0): activation: beginning transaction (timeout in 45 seconds)
Nov 26 09:13:50 box NetworkManager[580]: <info>  [1764144830.1957] dhcp6 (bridge0): state changed new lease
Nov 26 09:13:50 box NetworkManager[580]: <info>  [1764144830.1973] dhcp4 (bridge0): state changed new lease, address=192.168.X.Y, acd pending
Nov 26 09:13:50 box NetworkManager[580]: <info>  [1764144830.1977] dhcp4 (bridge0): state changed new lease, address=192.168.X.Y
Nov 26 09:13:57 box systemd[1]: NetworkManager-dispatcher.service: Deactivated successfully.

NM declares the Ethernet adapter "unmanaged", restores it's physical MAC address, drops it out of the bridge, auto-activates this "new" adapter as a new connection named "enp100s0" and auto-attaches it to the bridge - which now has a member with the same MAC address. The old connection "Ethernet slave" is no longer shown.

To remedy this, I only need to down the superfluous connection:

nmcli c down enp100s0

"Ethernet slave" will automatically re-activate and restores the bridge to it's normal state.

Is there something I missed in the configuration?

Last edited by -thc (2025-11-27 17:44:15)

seth · 2025-11-26 20:20:28

google has "unmanaged-nm-disabled" here and in https://bbs.archlinux.org/viewtopic.php?id=310281 and https://bbs.archlinux.org/viewtopic.php?id=310299 - and nowhere else.
So it's probably a recent introduction, https://gitlab.archlinux.org/archlinux/ … mmits/main
You could try to downgrade to 1.52.1 or 1.54.0 (from the involved dates 1.54.1 might very well be unaffected)

The other two threads have it on wifi NICs => power saving related? ASPM? ("pcie_aspm=off" kernel parameter)
Are there more network or pci or igc related messages around the sleep?

Possible mitigation via https://wiki.archlinux.org/title/Networ … ic_devices

-thc · 2025-11-27 06:47:40

Thanks, seth. I tried downgrading NM to 1.54.0 - no change. Seems not to be introduced recently.

I expect ignoring the physical MACs or "enp100s0" shouldn't work - this would also shut down one or both needed connections.
There are no other pci/igc related messages.

Did you notice that in both WiFi cases the procedure happens before going to sleep - where it makes a lot more sense?

seth · 2025-11-27 15:58:00

Did you notice that in both WiFi cases the procedure happens before going to sleep - where it makes a lot more sense?

I mostly brought those up to point out the rareness (if this was an older state it would probably show randomly up in some logs somewhere)
The pattern is now also in https://bbs.archlinux.org/viewtopic.php?id=310453 (and there, too, *after* the wakeup)
=> try 1.52.1 - if this is a new feature it was likely introduced in a major version update

The idea of https://wiki.archlinux.org/title/Networ … ic_devices would be to make NM not autoconfigure the NICs - ideally sparing you the bogus connection (but not affecting the explicit "Ethernet involuntary contributor" one)

-thc · 2025-11-27 17:43:51

Thanks - tried 1.52.1 - no change.

I recently virtualized Proxmox 9.1 and discovered that it's own primary bridge has an Ethernet slave with the same MAC as it's master.
So I dropped changing the MAC address of the slave - which leaves only the "aesthetic" side of this NM behavior (wrong connection name, weird looking NM applet).

I will mark this as "Abandoned".

Arch Linux

#1 2025-11-26 13:05:33

[Abandoned] Wakeup from suspend: NM botches re-activation of bridge

#2 2025-11-26 20:20:28

Re: [Abandoned] Wakeup from suspend: NM botches re-activation of bridge

#3 2025-11-27 06:47:40

Re: [Abandoned] Wakeup from suspend: NM botches re-activation of bridge

#4 2025-11-27 15:58:00

Re: [Abandoned] Wakeup from suspend: NM botches re-activation of bridge

#5 2025-11-27 17:43:51

Re: [Abandoned] Wakeup from suspend: NM botches re-activation of bridge

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