Proxmox VE 8.4 + Debian 12 VM: qemu-guest-agent responds to commands but qm shutdown hangs in "running (shutdown)" state

I'm running **Proxmox VE 8.4.1**, and I’m experiencing a strange behavior with a **Debian 12 (Bookworm)** VM: the qemu-guest-agent is clearly active and responding, but when I try to shut down the VM via qm shutdown , it never completes. The VM remains stuck in the state:

running (shutdown)

Also, the qm agent ping command returns **no output at all**. --- ### ✅ Working behavior: - Guest has qemu-guest-agent installed and running - Device /dev/virtio-ports/org.qemu.guest_agent.0 exists inside the VM - Agent is enabled via agent: 1 in qm config - Commands like the following return valid JSON:

qm guest cmd  get-osinfo  
qm guest cmd  get-time  
qm guest cmd  get-users  
qm guest cmd  network-get-interfaces

--- ### ❌ Failing behavior: - qm agent ping → **no output, no error** Example:

root@host:~# qm agent 100 ping
root@host:~#

- qm shutdown → executes, but VM remains stuck in "running (shutdown)" state - Restarted host and guest multiple times, same result --- ### 🔧 Setup: **Guest VM (Debian 12):**

# cat /etc/os-release
Debian GNU/Linux 12 (bookworm)

# qemu-ga --version
QEMU Guest Agent 7.2.17 (but tried also with 10.0.0+ds-2~bpo12+2 installed via bookworm-backports and nothing changes)

# ls -l /dev/virtio-ports/
crw------- 1 root root ... org.qemu.guest_agent.0

**Host (Proxmox):**

# pveversion
pve-manager/8.4.1/2a5fa54a8503f96d (running kernel: 6.8.12-11-pve)

# apt show pve-qemu-kvm
Version: 9.2.0-6

--- ### 📜 Logs (from journalctl -xe on the host):

Jul 14 16:20:42 hostname pvedaemon: start VM 100: UPID:hostname:00000000:00000000:00000000:qmstart:100:root@pam:
Jul 14 16:20:42 hostname pvedaemon:  starting task UPID:hostname:00000000:00000000:00000000:qmstart:100:root@pam:
Jul 14 16:20:43 hostname pvedaemon: VM 100 started with PID 516522.
Jul 14 16:20:43 hostname pvedaemon:  end task UPID:hostname:00000000:00000000:00000000:qmstart:100:root@pam: OK
Jul 14 16:20:44 hostname pvedaemon:  starting task UPID:hostname:00000000:00000000:00000000:vncproxy:100:root@pam:
Jul 14 16:20:44 hostname pvedaemon: starting vnc proxy UPID:hostname:00000000:00000000:00000000:vncproxy:100:root@pam:
Jul 14 16:21:08 hostname pvedaemon:  starting task UPID:hostname:00000000:00000000:00000000:qmshutdown:100:root@pam:
Jul 14 16:21:08 hostname pvedaemon: shutdown VM 100: UPID:hostname:00000000:00000000:00000000:qmshutdown:100:root@pam:
Jul 14 16:21:32 hostname pvedaemon:  end task UPID:hostname:00000000:00000000:00000000:vncproxy:100:root@pam: OK
Jul 14 16:21:36 hostname pvedaemon: VM 100 qmp command failed - VM 100 qmp command 'guest-ping' failed - got timeout
Jul 14 16:21:55 hostname pvedaemon: VM 100 qmp command failed - VM 100 qmp command 'guest-ping' failed - got timeout
Jul 14 16:22:14 hostname pvedaemon: VM 100 qmp command failed - VM 100 qmp command 'guest-ping' failed - unable to connect to VM 100 qga socket - timeout after 31 retries

--- ### 🤔 My theory: Since all other guest cmd commands work fine, it seems that **Proxmox is expecting a response from guest-ping**, and when it doesn’t receive it (or receives an empty response), it **fails to confirm the VM shut down properly** — which leads to the stuck "running (shutdown)" state. --- ## ❓ Question: What could be causing guest-ping (used internally by qm agent ping and qm shutdown) to fail or timeout, even when other guest cmd commands succeed? - Is there something about how qemu-ga communicates that might explain why guest-ping isn't acknowledged? - Could this be a bug or mismatch between Proxmox 8.4 and the QEMU Guest Agent in debian, tried bot native 7.2.17 and backports v10? - Is there a proper workaround to allow clean qm shutdown detection without guest-ping? Any insights from people using similar versions (QEMU 9+, guest-agent 10+, Proxmox 8) would be very appreciated. Thanks! --- Some images: Dump of serial after adding the serial port to the vm before the shutdown and after pressing the shutdown button in GUI interface. root@proxmox:~# qm terminal 100 starting serial terminal on interface serial0 (press Ctrl+O to exit) [ 26.693132] reboot: Power down nothing happens on serial after this