[qemu-kvm] Failed on repeatedly hotplug/unplug disk iothread enabled

// code placeholder
1.Boot vm

 /usr/libexec/qemu-kvm \
     -name 'avocado-vt-vm1'  \
     -sandbox on  \
     -machine q35,memory-backend=mem-machine_mem \
     -device '{"id": "pcie-root-port-0", "driver": "pcie-root-port", "multifunction": true, "bus": "pcie.0", "addr": "0x1", "chassis": 1}' \
     -device '{"id": "pcie-pci-bridge-0", "driver": "pcie-pci-bridge", "addr": "0x0", "bus": "pcie-root-port-0"}'  \
     -nodefaults \
     -device '{"driver": "VGA", "bus": "pcie.0", "addr": "0x2"}' \
     -m 30720 \
     -object '{"size": 32212254720, "id": "mem-machine_mem", "qom-type": "memory-backend-ram"}'  \
     -smp 10,maxcpus=10,cores=5,threads=1,dies=1,sockets=2  \
     -cpu 'Cascadelake-Server',ss=on,vmx=on,pdcm=on,hypervisor=on,tsc-adjust=on,umip=on,pku=on,md-clear=on,stibp=on,flush-l1d=on,arch-capabilities=on,xsaves=on,ibpb=on,ibrs=on,amd-stibp=on,amd-ssbd=on,rdctl-no=on,ibrs-all=on,skip-l1dfl-vmentry=on,mds-no=on,pschange-mc-no=on,tsx-ctrl=on,fb-clear=on,hle=off,rtm=off,kvm_pv_unhalt=on \
     -device '{"id": "pcie-root-port-1", "port": 1, "driver": "pcie-root-port", "addr": "0x1.0x1", "bus": "pcie.0", "chassis": 2}' \
     -device '{"driver": "qemu-xhci", "id": "usb1", "bus": "pcie-root-port-1", "addr": "0x0"}' \
     -device '{"driver": "usb-tablet", "id": "usb-tablet1", "bus": "usb1.0", "port": "1"}' \
     -object '{"qom-type": "iothread", "id": "iothread0"}' \
     -object '{"qom-type": "iothread", "id": "iothread1"}' \
     -device '{"id": "pcie-root-port-2", "port": 2, "driver": "pcie-root-port", "addr": "0x1.0x2", "bus": "pcie.0", "chassis": 3}' \
     -device '{"id": "virtio_scsi_pci0", "driver": "virtio-scsi-pci", "bus": "pcie-root-port-2", "addr": "0x0", "iothread": "iothread0"}' \
     -blockdev '{"node-name": "file_image1", "driver": "file", "auto-read-only": true, "discard": "unmap", "aio": "threads", "filename": "/home/kvm_autotest_root/images/rhel940-64-virtio-scsi.qcow2", "cache": {"direct": true, "no-flush": false}}' \
     -blockdev '{"node-name": "drive_image1", "driver": "qcow2", "read-only": false, "cache": {"direct": true, "no-flush": false}, "file": "file_image1"}' \
     -device '{"driver": "scsi-hd", "id": "image1", "drive": "drive_image1", "bootindex": 0, "write-cache": "on"}' \
     -device '{"id": "pcie-root-port-3", "port": 3, "driver": "pcie-root-port", "addr": "0x1.0x3", "bus": "pcie.0", "chassis": 4}' \
     -device '{"driver": "virtio-net-pci", "mac": "9a:21:b2:e0:6d:4b", "id": "idwbiXqo", "netdev": "iduN1RGA", "bus": "pcie-root-port-3", "addr": "0x0"}'  \
     -netdev tap,id=iduN1RGA,vhost=on \
     -vnc :5 \
     -monitor stdio \
     -qmp tcp:0:5955,server=on,wait=off \
     -rtc base=utc,clock=host,driftfix=slew  \
     -boot menu=off,order=cdn,once=c,strict=off \
     -enable-kvm \
     -device '{"id": "pcie_extra_root_port_0", "driver": "pcie-root-port", "multifunction": true, "bus": "pcie.0", "addr": "0x3", "chassis": 5}' \
     -chardev socket,id=socket-serial,path=/var/tmp/socket-serial,logfile=/var/tmp/file-serial.log,mux=on,server=on,wait=off \
     -serial chardev:socket-serial \
     -chardev file,path=/var/tmp/file-bios.log,id=file-bios \
     -device isa-debugcon,chardev=file-bios,iobase=0x402 \
 
2. hotplug disk
{"execute": "device_add", "arguments":{"id": "virtio_scsi_pci1", "driver": "virtio-scsi-pci", "bus": "pcie_extra_root_port_0", "addr": "0x0", "iothread": "iothread1"}, "id": "MSVjNpxq"}
{"execute": "blockdev-add", "arguments": {"node-name": "file_stg0", "driver": "file", "auto-read-only": true, "discard": "unmap", "aio": "threads", "filename": "/home/kvm_autotest_root/images/storage0.qcow2", "cache": {"direct": true, "no-flush": false}}, "id": "uNRhq5lR"}
{"execute": "blockdev-add", "arguments": {"node-name": "drive_stg0", "driver": "qcow2", "read-only": false, "cache":{"direct": true, "no-flush": false}, "file": "file_stg0"}, "id": "VtvrjLkH"}
{"execute": "device_add", "arguments":
{"driver": "scsi-hd", "id": "stg0", "bus": "virtio_scsi_pci1.0", "drive": "drive_stg0", "write-cache": "on"}
, "id": "pWLotHhW"}

3. check the disk in guest,should added
lsblk

4. unplug disk
{"execute": "device_del", "arguments":{"id": "stg0"}, "id": "R81C1q8p"}
{"execute": "blockdev-del", "arguments":{"node-name": "drive_stg0"}, "id": "EAiI2LVe"}
{"execute": "blockdev-del", "arguments":{"node-name": "file_stg0"}, "id": "IJRbWqTG"}
{"execute": "device_del", "arguments":{"id": "virtio_scsi_pci1"}, "id": "w6mivmt2"}

5. check the disk in guest, should deleted
lsblk

6. repeat steps 2-5 100times