From f9a00a5ce0796e3420f0ee2ccbace7d771fa8e7d Mon Sep 17 00:00:00 2001
From: pierventre <pier@opennetworking.org>
Date: Mon, 25 Oct 2021 18:49:09 +0200
Subject: [PATCH] Fix npe during hostVanished handling

java.lang.NullPointerException: null
	at org.onosproject.net.host.impl.HostManager$InternalHostProviderService.hostVanished(HostManager.java:573) ~[?:?]
	at org.onosproject.provider.netcfghost.NetworkConfigHostProvider.removeHost(NetworkConfigHostProvider.java:189) ~[?:?]
	at org.onosproject.provider.netcfghost.NetworkConfigHostProvider$InternalNetworkConfigListener.event(NetworkConfigHostProvider.java:274) ~[?:?]
	at org.onosproject.provider.netcfghost.NetworkConfigHostProvider$InternalNetworkConfigListener.event(NetworkConfigHostProvider.java:222) ~[?:?]
	at org.onosproject.event.ListenerRegistry.process(ListenerRegistry.java:66) [!/:?]
	at org.onosproject.event.impl.CoreEventDispatcher$DispatchLoop.process(CoreEventDispatcher.java:198) [!/:?]
	at org.onosproject.event.impl.CoreEventDispatcher$DispatchLoop.run(CoreEventDispatcher.java:180) [!/:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) [?:?]
	at java.util.concurrent.FutureTask.run(FutureTask.java:264) [?:?]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) [?:?]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) [?:?]
	at java.lang.Thread.run(Thread.java:834) [?:?]

Change-Id: If6e3978798d5fb11b3f5b1344b551b9f3cd3e51d
(cherry picked from commit 3a615560678cb83fa41f393fa59c346cdae659e2)
---
 .../java/org/onosproject/net/host/impl/HostManager.java     | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/core/net/src/main/java/org/onosproject/net/host/impl/HostManager.java b/core/net/src/main/java/org/onosproject/net/host/impl/HostManager.java
index 46cbc0a7da..a02159c933 100644
--- a/core/net/src/main/java/org/onosproject/net/host/impl/HostManager.java
+++ b/core/net/src/main/java/org/onosproject/net/host/impl/HostManager.java
@@ -562,6 +562,7 @@ public class HostManager
         public void hostVanished(HostId hostId) {
             checkNotNull(hostId, HOST_ID_NULL);
             checkValidity();
+            // TODO SDFAB-718 rethink HostStore APIs to allow atomic operations
             Host host = store.getHost(hostId);
 
             if (!allowedToChange(hostId)) {
@@ -569,6 +570,11 @@ public class HostManager
                 return;
             }
 
+            if (host == null) {
+                log.info("Request to remove {} is ignored due to host not present in the store", hostId);
+                return;
+            }
+
             if (monitorHosts) {
                 host.ipAddresses().forEach(ip -> {
                     monitor.stopMonitoring(ip);