Hyper-V virtual machine with Dynamic Memory gets unresponsive while logs are flooded with `hv_balloon: Unhandled message:`

Issue

• Hyper-V virtual machine with Dynamic Memory gets unresponsive.

• hv_balloon driver generates excessive logs regarding unhandled messages like the following:

  [366966.594043] hv_balloon: Unhandled message: type: 30966
  [366966.594065] hv_balloon: Unhandled message: type: 30966
  [366966.594087] hv_balloon: Unhandled message: type: 30966
  [366966.594107] hv_balloon: Unhandled message: type: 46394
  [366966.594128] hv_balloon: Unhandled message: type: 20385
  
  -and eventually also-
  
  systemd-journald[713]: Missed 17752 kernel messages
  kernel: hv_balloon: Unhandled message: type: 13661
  systemd-journald[713]: Missed 17752 kernel messages
  kernel: hv_balloon: Unhandled message: type: 8192
  systemd-journald[713]: Missed 12418 kernel messages
  

• Due to excessive log generation, both ksoftirqd and systemd-journald are hanging, leading to performance degradation or even complete system unresponsiveness.