From 96a9597720f6ace61f686b6461936966dfb471e7 Mon Sep 17 00:00:00 2001
From: Sven Rebhan <36194019+srebhan@users.noreply.github.com>
Date: Wed, 9 Aug 2023 17:41:17 +0200
Subject: [PATCH] fix(inputs.opcua_listener): Avoid segfault if subscription
 was not successful (#13742)

---
 plugins/inputs/opcua_listener/subscribe_client.go | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/plugins/inputs/opcua_listener/subscribe_client.go b/plugins/inputs/opcua_listener/subscribe_client.go
index a42738df2..872dffc08 100644
--- a/plugins/inputs/opcua_listener/subscribe_client.go
+++ b/plugins/inputs/opcua_listener/subscribe_client.go
@@ -83,10 +83,11 @@ func (o *SubscribeClient) Connect() error {
 }
 
 func (o *SubscribeClient) Stop(ctx context.Context) <-chan struct{} {
-	o.Log.Debugf("Opc Subscribe Stopped")
-	err := o.sub.Cancel(ctx)
-	if err != nil {
-		o.Log.Warn("Cancelling OPC UA subscription failed with error ", err)
+	o.Log.Debugf("Stopping OPC subscription...")
+	if o.sub != nil {
+		if err := o.sub.Cancel(ctx); err != nil {
+			o.Log.Warn("Cancelling OPC UA subscription failed with error ", err)
+		}
 	}
 	closing := o.OpcUAInputClient.Stop(ctx)
 	o.processingCancel()