Proxmox – CPU stuck warning

watchdog: BUG: soft lockup - CPU#7 stuck for 22s

Annoying bug, makes processes and VMs stuck. Spent several days trying to figure it out. Got many unhappy customer. Only getting this son a big shared-hosting server – not all, just one with no specific pattern.

The best so far solution to fix this:

  • disable “Ballooning device”
  • disable “Allow KSM”
  • no-cache for drives
  • do not use IO thread for drives
  • set AsyncIO to default “io_uring”

Of course – you need to reboot it, make sure all VMs on the host have these settings. Best is to also reboot host.