HNS service not responding

[wenyingd]

Description

When I tried to remove an existing HNSEndpoint with command "Get-HnsEndpoint -Id xxx | Remove-HnsEndpoint", the command is hang, and not returned anything. Even if I tried with ctrl-C to interrupt the "remove" command, nothing returned.

Steps to reproduce the issue:

1. Create a new HnsEndpoint
2. Attach to a container
3. Remove the HnsEndpoint

Describe the results you received:
Nothing returned, the command is never complete.

Describe the results you expected:
The command should return after execution. If there is any error, return the error.

Additional information you deem important (e.g. issue happens only occasionally):

Output of docker version:

> docker version
Client: Docker Engine - Enterprise
 Version:           19.03.5
 API version:       1.40
 Go version:        go1.12.12
 Git commit:        2ee0c57608
 Built:             11/13/2019 08:00:16
 OS/Arch:           windows/amd64
 Experimental:      false

Server: Docker Engine - Enterprise
 Engine:
  Version:          19.03.5
  API version:      1.40 (minimum version 1.24)
  Go version:       go1.12.12
  Git commit:       2ee0c57608
  Built:            11/13/2019 07:58:51
  OS/Arch:          windows/amd64
  Experimental:     false

Output of docker info:

> docker info
Client:
 Debug Mode: false
 Plugins:
  cluster: Manage Docker clusters (Docker Inc., v1.2.0)

Server:
 Containers: 1
  Running: 0
  Paused: 0
  Stopped: 1
 Images: 2
 Server Version: 19.03.5
 Storage Driver: windowsfilter
  Windows:
 Logging Driver: json-file
 Plugins:
  Volume: local
  Network: ics internal l2bridge l2tunnel nat null overlay private transparent
  Log: awslogs etwlogs fluentd gcplogs gelf json-file local logentries splunk syslog
 Swarm: inactive
 Default Isolation: process
 Kernel Version: 10.0 17763 (17763.1.amd64fre.rs5_release.180914-1434)
 Operating System: Windows Server 2019 Standard Version 1809 (OS Build 17763.1039)
 OSType: windows
 Architecture: x86_64
 CPUs: 2
 Total Memory: 3.999GiB
 Name: WIN-N9SMVQ6695B
 ID: E7PU:6CRL:3KXW:VMYV:NKU2:JRMY:2RQP:4UZR:FWUV:GJ4P:OQXR:FLS6
 Docker Root Dir: C:\ProgramData\docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false

Additional environment details (AWS, VirtualBox, physical, etc.):

[wenyingd]

Hi all, I have dumped the call stack of hns service using windbg, and got this stack shown in the following picture on the stucking thread:

Having dump OVSext trace, and found that OVSext driver has received the mssage OID_SWITCH_NIC_DISCONNECT and replied it, but OVSext didn't receive message OID_SWITCH_NIC_DELETE which is expected as the next message.