Suspend fails, kworker acts up, Ethernet issue e1000e

Starting today, I'm having trouble suspending in Kubuntu 24.04.

The system starts going into suspend mode but immediately wakes up again. Looking at dmesg I see

[ 6651.094136] printk: Suspending console(s) (use no_console_suspend to debug)[ 6651.125166] e1000e: EEE TX LPI TIMER: 00000011[ 6651.390957] e1000e 0000:00:1f.6: PM: pci_pm_suspend(): e1000e_pm_suspend+0x0/0xa0 [e1000e] returns -2[ 6651.390992] e1000e 0000:00:1f.6: PM: dpm_run_callback(): pci_pm_suspend+0x0/0x1b0 returns -2[ 6651.390999] e1000e 0000:00:1f.6: PM: failed to suspend async: error -2[ 6651.448565] PM: Some devices failed to suspend, or early wake event detected

Possibly related, a bit further down, I have

[ 6652.552849] PM: suspend exit[ 6652.553084] thermal thermal_zone10: failed to read out thermal zone (-61)[ 6654.902420] e1000e 0000:00:1f.6 enp0s31f6: Hardware Error[ 6656.229366] e1000e 0000:00:1f.6 enp0s31f6: NIC Link is Down[ 6658.248107] e1000e 0000:00:1f.6 enp0s31f6: Hardware Error[ 6660.706813] workqueue: e1000_watchdog_task [e1000e] hogged CPU for >10000us 4 times, consider switching to WQ_UNBOUND[ 6660.709569] iwlwifi 0000:00:14.3: WRT: Invalid buffer destination[ 6660.864924] iwlwifi 0000:00:14.3: Not valid error log pointer 0x0027B0C0 for RT uCode[ 6660.864952] iwlwifi 0000:00:14.3: WFPM_UMAC_PD_NOTIFICATION: 0x1f[ 6660.864971] iwlwifi 0000:00:14.3: WFPM_LMAC2_PD_NOTIFICATION: 0x1f[ 6660.864978] iwlwifi 0000:00:14.3: WFPM_AUTH_KEY_0: 0x80[ 6660.864987] iwlwifi 0000:00:14.3: CNVI_SCU_SEQ_DATA_DW9: 0x0[ 6660.865819] iwlwifi 0000:00:14.3: RFIm is deactivated, reason = 4

After the system as come back up again, I'm getting high CPU usage by kworker instances, for example kworker/0:2-events. Before my first suspend attempt, kworker behaves normally (not visible in top).

e1000e seems to be related to Ethernet. I saw a bug report that seems related at https://bugzilla.kernel.org/show_bug.cgi?id=205015 but that relates to kernel 5.3.0. I am using 6.8.0-45.

What would be good trouble shooting steps? Downgrade to a previous kernel? (I have not consciously updated the kernel since before this happened.)

Edit: I noted that after the problem occurs, my laptop's Ethernet connection does not work. Conversely, if I have an Ethernet cable connected before I first try to suspend, then the suspend & resume works as normal and the Ethernet connection works as normal. (But using an USB-C network adapter does not help.)

Edit 2: I tried disabling wake-on-LAN by doing sudo ethtool -s <my eth interface> wol d and that appears to have solved the problem at least for now. I don't need WOL functionality so that's fine but it would still be interesting to know what happened since before this problem started to occur.