Description of problem:
guest still wait for vhostuserport connected. When use pexpect and time.sleep to start a testpmd

Version-Release number of selected component (if applicable):
dpdk version:
dpdk-22.11-1.el9.x86_64
dpdk-tools-22.11-1.el9.x86_64
# pip3 list | grep pexpect
pexpect              4.8.0
python3-3.9.16-1.el9.x86_64
How reproducible: 100%


Steps to Reproduce:
1. create a python script as below:
import sys
import pexpect
testpmd_cmd=sys.argv[1]
cpu1=int(sys.argv[2])
cpu2=int(sys.argv[3])
cpu3=int(sys.argv[4])
port1=int(sys.argv[5])
port2=int(sys.argv[6])
port3=int(sys.argv[7])
port4=int(sys.argv[8])
#exe.logfile_read = sys.stdout
#exe.logfile = sys.stdout
#cmd
cmd="{} -l {},{},{} -n 4 --socket-mem 1024,1024 --vdev net_vhost0,iface=/tmp/vhostuser/vhost0,client=1,queues=1,iommu-support=1 --vdev net_vhost1,iface=/tmp/vhostuser/vhost1,client=1,queues=1,iommu-support=1 -- -i --nb-cores=2 --txq=1 --rxq=1 --forward-mode=io".format(testpmd_cmd,cpu1,cpu2,cpu3)
exe=pexpect.spawn(cmd, encoding='utf-8')
exe.logfile = sys.stdout
exe.expect(['Done',pexpect.EOF, pexpect.TIMEOUT])
#exe.sendline('set portlist 0,2,1,3')
exe.sendline('set portlist {},{},{},{}'.format(port1,port2,port3,port4))
exe.expect('testpmd>')
exe.sendline('start')
exe.expect('testpmd>')
#exe.sendline('show port summary all')
exe.expect('testpmd>')
import time
time.sleep(6000)

2. create a guest xml as below
<domain type='kvm'>
  <name>g1</name>
  <memory unit='KiB' dumpCore="on">8388608</memory>
  <currentMemory unit='KiB'>8388608</currentMemory>
  <memoryBacking>
    <hugepages>
      <page size='1048576' unit='KiB'/>
    </hugepages>
    <locked/>
    <access mode='shared'/>
  </memoryBacking>
  <vcpu placement='static'>3</vcpu>
  <cputune>
    <vcpupin vcpu='0' cpuset='26'/>
    <vcpupin vcpu='1' cpuset='4'/>
    <vcpusched vcpus='1' scheduler='fifo' priority='1'/>
    <vcpupin vcpu='2' cpuset='28'/>
    <vcpusched vcpus='2' scheduler='fifo' priority='1'/>
    <emulatorpin cpuset='6'/>
  </cputune>
  <numatune>
    <memory mode='strict' nodeset='0'/>
    <memnode cellid='0' mode='strict' nodeset='0'/>
  </numatune>
  <resource>
    <partition>/machine</partition>
  </resource>
  <os>
    <type arch='x86_64' machine='q35'>hvm</type>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
    <pmu state='off'/>
    <vmport state='off'/>
    <ioapic driver='qemu'/>
  </features>
  <cpu mode='host-passthrough' check='none'>
    <feature policy='require' name='tsc-deadline'/>
    <numa>
      <cell id='0' cpus='0-2' memory='8388608' unit='KiB' memAccess='shared'/>
    </numa>
  </cpu>
  <clock offset='utc'>
    <timer name='rtc' tickpolicy='catchup'/>
    <timer name='pit' tickpolicy='delay'/>
    <timer name='hpet' present='no'/>
  </clock>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <pm>
    <suspend-to-mem enabled='no'/>
    <suspend-to-disk enabled='no'/>
  </pm>
  <devices>
    <emulator>/usr/libexec/qemu-kvm</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2'/>
      <source file='/var/lib/libvirt/images/g1.qcow2'/>
      <backingStore/>
      <target dev='vda' bus='virtio'/>
      <alias name='virtio-disk0'/>
      <address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
    </disk>
    <controller type='usb' index='0' model='none'>
      <alias name='usb'/>
    </controller>
    <controller type='pci' index='0' model='pcie-root'>
      <alias name='pcie.0'/>
    </controller>
    <controller type='pci' index='1' model='pcie-root-port'>
      <model name='pcie-root-port'/>
      <target chassis='1' port='0x10'/>
      <alias name='pci.1'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    </controller>
    <controller type='pci' index='2' model='pcie-root-port'>
      <model name='pcie-root-port'/>
      <target chassis='2' port='0x11'/>
      <alias name='pci.2'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </controller>
    <controller type='pci' index='3' model='pcie-root-port'>
      <model name='pcie-root-port'/>
      <target chassis='3' port='0x8'/>
      <alias name='pci.3'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
    </controller>
    <controller type='pci' index='4' model='pcie-root-port'>
      <model name='pcie-root-port'/>
      <target chassis='4' port='0x9'/>
      <alias name='pci.4'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
    </controller>
    <controller type='pci' index='5' model='pcie-root-port'>
      <model name='pcie-root-port'/>
      <target chassis='5' port='0xa'/>
      <alias name='pci.5'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
    </controller>
    <controller type='pci' index='6' model='pcie-root-port'>
      <model name='pcie-root-port'/>
      <target chassis='6' port='0xb'/>
      <alias name='pci.6'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </controller>
    <controller type='sata' index='0'>
      <alias name='ide'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x1f' function='0x2'/>
    </controller>
    <interface type='bridge'>
      <mac address='52:54:00:01:02:03'/>
      <source bridge='virbr0'/>
      <model type='virtio'/>
    </interface>
<interface type='vhostuser'>
  <mac address='00:de:ad:00:00:01'/>
  <source type='unix' path='/tmp/vhostuser/vhost0' mode='server'/>
  <model type='virtio'/>
  <driver name='vhost' rx_queue_size='1024' tx_queue_size='1024' iommu='off' ats='off'>
  <host mrg_rxbuf='off'/>
  </driver>
  <address type='pci' domain='0x0000' bus='0x3' slot='0x00' function='0x0'/>
</interface>
<interface type='vhostuser'>
  <mac address='00:de:ad:00:00:02'/>
  <source type='unix' path='/tmp/vhostuser/vhost1' mode='server'/>
  <model type='virtio'/>
  <driver name='vhost' rx_queue_size='1024' tx_queue_size='1024' iommu='off' ats='off'>
  <host mrg_rxbuf='off'/>
  </driver>
  <address type='pci' domain='0x0000' bus='0x4' slot='0x00' function='0x0'/>
</interface>
    <serial type='pty'>
      <source path='/dev/pts/1'/>
      <target type='isa-serial' port='0'>
        <model name='isa-serial'/>
      </target>
      <alias name='serial0'/>
    </serial>
    <console type='pty' tty='/dev/pts/1'>
      <source path='/dev/pts/1'/>
      <target type='serial' port='0'/>
      <alias name='serial0'/>
    </console>
    <input type='mouse' bus='ps2'>
      <alias name='input0'/>
    </input>
    <input type='keyboard' bus='ps2'>
      <alias name='input1'/>
    </input>
    <graphics type='vnc' port='5900' autoport='yes' listen='0.0.0.0'>
      <listen type='address' address='0.0.0.0'/>
    </graphics>
    <video>
      <model type='cirrus' vram='16384' heads='1' primary='yes'/>
      <alias name='video0'/>
      <address type='pci' domain='0x0000' bus='0x05' slot='0x00' function='0x0'/>
    </video>
    <memballoon model='virtio'>
      <alias name='balloon0'/>
      <address type='pci' domain='0x0000' bus='0x06' slot='0x00' function='0x0'/>
    </memballoon>
    <iommu model='intel'>
      <driver intremap='on' caching_mode='on' iotlb='on'/>
    </iommu>
  </devices>
</domain>

3. use script which create in step1 to start dpdk-testpmd
python3 /root/start_testpmd.py dpdk-testpmd 47 23 46 0 2 1 3
# ps -aux | grep testpmd
root        3525  0.0  0.0  11932 10184 pts/1    S+   04:59   0:00 python3 /root/start_testpmd.py dpdk-testpmd 47 23 46 0 2 1 3
root        3526  199  0.1 155498032 79128 pts/3 SLsl+ 04:59 141:36 /usr/bin/dpdk-testpmd -l 47,23,46 -n 4 --socket-mem 1024 1024 --vdev net_vhost0,iface=/tmp/vhostuser/vhost0,client=1,queues=1,iommu-support=1 --vdev net_vhost1,iface=/tmp/vhostuser/vhost1,client=1,queues=1,iommu-support=1 -- -i --nb-cores=2 --txq=1 --rxq=1 --forward-mode=io

4. start guest
virsh create g1.xml

5. reboot guest
virsh reboot g1

6 check guest log as below:
2023-03-22T16:58:19.960304Z qemu-kvm: -chardev socket,id=charnet1,path=/tmp/vhostuser/vhost0,server=on: info: QEMU waiting for connection on: disconnected:unix:/tmp/vhostuser/vhost0,server=on
2023-03-22T18:10:59.592387Z qemu-kvm: -chardev socket,id=charnet2,path=/tmp/vhostuser/vhost1,server=on: info: QEMU waiting for connection on: disconnected:unix:/tmp/vhostuser/vhost1,server=on
char device redirected to /dev/pts/1 (label charserial0)
2023-03-22T18:10:59.663982Z qemu-kvm: -netdev {"type":"vhost-user","chardev":"charnet1","id":"hostnet1"}: Failed to read msg header. Read -1 instead of 12. Original request 1.
2023-03-22T18:10:59.664013Z qemu-kvm: -netdev {"type":"vhost-user","chardev":"charnet1","id":"hostnet1"}: vhost_backend_init failed: Protocol error
2023-03-22T18:10:59.664024Z qemu-kvm: -netdev {"type":"vhost-user","chardev":"charnet1","id":"hostnet1"}: failed to init vhost_net for queue 0
2023-03-22T18:10:59.664059Z qemu-kvm: -netdev {"type":"vhost-user","chardev":"charnet1","id":"hostnet1"}: info: QEMU waiting for connection on: disconnected:unix:/tmp/vhostuser/vhost0,server=on

Actual results:
1. guest reboot failed and still waiting vhostuser port connected.

Expected results:
2. guest reboot as well

Additional info:
if I use exe.interact() to instead of time.sleep, guest reboot as well.
import sys
import pexpect
#exe.logfile_read = sys.stdout
#exe.logfile = sys.stdout
#cmd
cmd="dpdk-testpmd -n 4 --socket-mem 1024,1024 --vdev net_vhost0,iface=/tmp/vhostuser/vhost0,client=1,queues=1,iommu-support=1 --vdev net_vhost1,iface=/tmp/vhostuser/vhost1,client=1,queues=1,iommu-support=1 -- -i --nb-cores=1 --txq=1 --rxq=1 --forward-mode=io"
exe=pexpect.spawn(cmd, encoding='utf-8')
exe.logfile = sys.stdout
exe.expect(['Done',pexpect.EOF, pexpect.TIMEOUT])
#exe.sendline('set portlist 0,2,1,3')
exe.sendline('set portlist 0,1')
exe.expect('testpmd>')
exe.sendline('start')
exe.expect('testpmd>')
#exe.sendline('show port summary all')
exe.expect('testpmd>')
exe.logfile = None
exe.interact()

run same test script can't hit this issue on dpdk-21.11-2.el9_0