Virtual Machine at 100% CPU load when passing USB audio device to VM

[agners]

Describe the issue you are experiencing

When passing a USB port with a USB audio device plugged-in to the virtual machine, the machine suddenly starts consuming 100% (1 core) after a while. From top running on the HAOS shell it seems that ksoftirq and Pulseaudio are to blame:

    PID USER      PR  NI    VIRT    RES  %CPU  %MEM     TIME+ S COMMAND                                                                                                                                                                                                                                                      
     24 root      20   0    0.0m   0.0m  98.4   0.0     15,06 R [ksoftirqd/1]                                                                                                                                                                                                                                                
 800156 root       9 -11  102.0m  13.4m   4.7   0.7  18:18.66 S pulseaudio --system --disallow-exit --exit-idle-time=-1 --disable-shm -vvv

Looking at the interrupts it seems that they are continously counting up (at a rather high rate of 50k/s):

# cat /proc/interrupts 
           CPU0       CPU1
...
 37:          0 3786165586  PCI-MSIX-0000:07:1b.0   0-edge      xhci_hcd

Restarting the Audio plug-in stops the high CPU load. After a couple of days it suddenly comes back.

This is the Proxmox specific issue reported in https://github.com/home-assistant/plugin-audio/issues/60.

What operating system image do you use?

ova (for Virtual Machines)

What version of Home Assistant Operating System is installed?

15.2.dev20250410

Did the problem occur after upgrading the Operating System?

No

Hardware details

Proxmox 8.4.1 on a Intel NUC10i5FNH.

Steps to reproduce the issue

1. Use Proxmox
2. Forward an Audio device to the virtual machine (I've used the port forwarding mechanism, not sure if that is relevant)
3. Wait for a few days for the problem to appear

Anything in the Supervisor logs that might be useful for us?

No logs coincide with the CPU spike/seem to be related to audio plug-in

Anything in the Host logs that might be useful for us?

No logs coincide with the CPU spike/seem to be related to audio plug-in

System information

System Information

version	core-2025.5.0.dev202504220235
installation_type	Home Assistant OS
dev	true
hassio	true
docker	true
user	root
virtualenv	false
python_version	3.13.2
os_name	Linux
os_version	6.12.23-haos
arch	x86_64
timezone	Europe/Zurich
config_dir	/config

Home Assistant Cloud

logged_in	false
can_reach_cert_server	ok
can_reach_cloud_auth	ok
can_reach_cloud	ok

Home Assistant Supervisor

host_os	Home Assistant OS 15.2.dev20250410
update_channel	dev
supervisor_version	supervisor-2025.04.1.dev2101
agent_version	1.7.2
docker_version	28.0.4
disk_total	30.8 GB
disk_used	7.3 GB
healthy	true
supported	true
host_connectivity	true
supervisor_connectivity	true
ntp_synchronized	true
virtualization	kvm
board	ova
supervisor_api	ok
version_api	ok
installed_addons	Terminal & SSH (9.16.0), Studio Code Server (5.19.1), OpenThread Border Router (2.13.0), MariaDB (2.7.2), VLC (0.3.0), TellStick (2.1.0), Matter Server (7.0.0), Google Assistant SDK (2.5.0), Glances (0.21.1)

Dashboards

dashboards	2
resources	0
views	0
mode	storage

Recorder

oldest_recorder_run	April 11, 2025 at 7:59 AM
current_recorder_run	April 22, 2025 at 9:49 AM
estimated_db_size	11.26 MiB
database_engine	sqlite
database_version	3.48.0

Additional information

No response