From d5cf34ef81302cdc3632859a41a3303a041b35f9 Mon Sep 17 00:00:00 2001
From: Kevin Schoedel <67607049+kpschoedel@users.noreply.github.com>
Date: Thu, 9 Sep 2021 13:01:39 -0400
Subject: [PATCH] Fix EventHandlerDelegate crash (#9569)

#### Problem

3a505010973c #9366 caused a crash. In `AddEventHandlerDelegate()`,
`lDelegate` was accidentally a stack variable instead of a reference to
the caller-supplied storage.

This affects all platforms using LwIP.

#### Change overview

Add one small but important `&`.

Fixes #9563 _ESP32&ESP32C3 crash on system layer_

#### Testing

all-clusters-app on M5Stack
---
 src/system/SystemLayerImplLwIP.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/system/SystemLayerImplLwIP.cpp b/src/system/SystemLayerImplLwIP.cpp
index b94745659deeb1..e7032941b524d5 100644
--- a/src/system/SystemLayerImplLwIP.cpp
+++ b/src/system/SystemLayerImplLwIP.cpp
@@ -147,7 +147,7 @@ CHIP_ERROR LayerImplLwIP::HandleSystemLayerEvent(Object & aTarget, EventType aEv
 
 CHIP_ERROR LayerImplLwIP::AddEventHandlerDelegate(EventHandlerDelegate & aDelegate)
 {
-    LwIPEventHandlerDelegate lDelegate = static_cast<LwIPEventHandlerDelegate &>(aDelegate);
+    LwIPEventHandlerDelegate & lDelegate = static_cast<LwIPEventHandlerDelegate &>(aDelegate);
     VerifyOrReturnError(lDelegate.GetFunction() != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
     lDelegate.Prepend(mEventDelegateList);
     return CHIP_NO_ERROR;