Cloned from https://issues.redhat.com/browse/RHEL-64714

What were you trying to do that didn't work?

After reverting a snapshot, remove an attached interface device. The virsh command exits successfully but the device is still present.

What is the impact of this issue to you?

We can't unplug devices while using snapshots.

Please provide the package NVR for which the bug is seen:

libvirt-10.8.0-2.el10.x86_64
qemu-kvm-9.1.0-3.el10.x86_64

How reproducible is this bug?:

100%

Steps to reproduce

1. Start a VM without an interface device

2. [root@libvirt-rhel-9 ~]# cat iface.xml 
   <interface type="network">
         <mac address="9a:44:3c:0d:49:9e" />
         <source network="default" portid="608aa754-a37f-4417-ad5c-58da62d08cc5" bridge="virbr0" />
         <target dev="vnet1" />
         <model type="virtio" />
         <driver queues="2" />
         <alias name="net0" />
         <address type="pci" domain="0x0000" bus="0x01" slot="0x00" function="0x0" />
       <coalesce><rx><frames max="32" /></rx></coalesce></interface>
   
   [root@libvirt-rhel-9 ~]# virsh attach-device avocado-vt-vm1 iface.xml --live
   Device attached successfully
   
   [root@libvirt-rhel-9 ~]# virsh snapshot-create-as avocado-vt-vm1 --memspec /tmp/mem1,snapshot=external --diskspec vda,snapshot=external,file=/tmp/disk1
   Domain snapshot 1729768744 created
   [root@libvirt-rhel-9 ~]# virsh snapshot-revert avocado-vt-vm1 --current
   Domain snapshot 1729768744 reverted
   
   [root@libvirt-rhel-9 ~]# virsh detach-interface avocado-vt-vm1 --type network --mac 9a:44:3c:0d:49:9e --live
   Interface detached successfully
   

1. # virsh dumpxml avocado-vt-vm1 --xpath //interface

    

Expected results

The command returns empty. The device has been removed.

Actual results

The interface is still present.
When I try to check in the guest if the device is still present the VM is stuck:

[root@localhost ~]# ip link
[   88.061610] watchdog: BUG: soft lockup - CPU#1 stuck for 53s! [kworker/1:2:260]

Message from syslogd@localhost at Oct 24 19:38:58 ...
 kernel:watchdog: BUG: soft lockup - CPU#1 stuck for 53s! [kworker/1:2:260]
...

Additional information

1. This does not reproduce with a simpler interface definition

   <interface type="network">
         <mac address="9a:44:3c:0d:49:9e" />
         <source network="default"/>
         <model type="virtio" />
   </interface>
   

1. This does not reproduce with qemu-kvm-9.0.0-10.el9_5
2.  

    # virsh event --all --loop 

   doesn't observe any device-removed event.