From 782b361fb1fc3ce3aa74553777c42d28bed31dd4 Mon Sep 17 00:00:00 2001
From: Kevin Schoedel <kpschoedel@google.com>
Date: Thu, 16 Dec 2021 14:49:05 -0500
Subject: [PATCH] Avoid crash in reporting::Engine::ScheduleRun()

#### Problem

`reporting::Engine::ScheduleRun()` crashes if invoked after
`SessionManager` has shut down.

#### Change overview

Check pointers.

#### Testing

Verified using pending PR #13060 with
```
server start
server stop
exit
```
which crashes without this change.
---
 src/app/reporting/Engine.cpp | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/app/reporting/Engine.cpp b/src/app/reporting/Engine.cpp
index 089d2dae3b46ee..79471aef7556f6 100644
--- a/src/app/reporting/Engine.cpp
+++ b/src/app/reporting/Engine.cpp
@@ -432,16 +432,24 @@ CHIP_ERROR Engine::ScheduleRun()
         return CHIP_NO_ERROR;
     }
 
-    if (InteractionModelEngine::GetInstance()->GetExchangeManager() != nullptr)
+    Messaging::ExchangeManager * exchangeManager = InteractionModelEngine::GetInstance()->GetExchangeManager();
+    if (exchangeManager == nullptr)
     {
-        mRunScheduled = true;
-        return InteractionModelEngine::GetInstance()->GetExchangeManager()->GetSessionManager()->SystemLayer()->ScheduleWork(Run,
-                                                                                                                             this);
+        return CHIP_ERROR_INCORRECT_STATE;
     }
-    else
+    SessionManager * sessionManager = exchangeManager->GetSessionManager();
+    if (sessionManager == nullptr)
+    {
+        return CHIP_ERROR_INCORRECT_STATE;
+    }
+    System::Layer * systemLayer = sessionManager->SystemLayer();
+    if (systemLayer == nullptr)
     {
         return CHIP_ERROR_INCORRECT_STATE;
     }
+    ReturnErrorOnFailure(systemLayer->ScheduleWork(Run, this));
+    mRunScheduled = true;
+    return CHIP_NO_ERROR;
 }
 
 void Engine::Run()