From dd295df6439ebc4e87e9f7b269ae39b15a5886b3 Mon Sep 17 00:00:00 2001
From: Etan Cohen <etancohen@google.com>
Date: Wed, 20 Jan 2021 21:04:02 -0800
Subject: [PATCH] [Provider Model] Check against race condition

There can be a race condition of the timeout and operation
completion both getting executed - both setting the callback
to null - which causes the other one to have an NPE.

Bug: 175084231
Test: Testing rapid succession recovery operations
Change-Id: If9d8418f1535d0e075c4abf2723c4b2734e8fa1a
---
 .../ConnectivitySubsystemsRecoveryManager.java           | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/packages/SettingsLib/src/com/android/settingslib/connectivity/ConnectivitySubsystemsRecoveryManager.java b/packages/SettingsLib/src/com/android/settingslib/connectivity/ConnectivitySubsystemsRecoveryManager.java
index 02d1c2e65c8dc..64cb0f1b7885f 100644
--- a/packages/SettingsLib/src/com/android/settingslib/connectivity/ConnectivitySubsystemsRecoveryManager.java
+++ b/packages/SettingsLib/src/com/android/settingslib/connectivity/ConnectivitySubsystemsRecoveryManager.java
@@ -210,7 +210,8 @@ public class ConnectivitySubsystemsRecoveryManager {
     }
 
     private void checkIfAllSubsystemsRestartsAreDone() {
-        if (!mWifiRestartInProgress && !mTelephonyRestartInProgress) {
+        if (!mWifiRestartInProgress && !mTelephonyRestartInProgress
+                && mCurrentRecoveryCallback != null) {
             mCurrentRecoveryCallback.onSubsystemRestartOperationEnd();
             mCurrentRecoveryCallback = null;
         }
@@ -283,8 +284,10 @@ public class ConnectivitySubsystemsRecoveryManager {
                     stopTrackingTelephonyRestart();
                     mWifiRestartInProgress = false;
                     mTelephonyRestartInProgress = false;
-                    mCurrentRecoveryCallback.onSubsystemRestartOperationEnd();
-                    mCurrentRecoveryCallback = null;
+                    if (mCurrentRecoveryCallback != null) {
+                        mCurrentRecoveryCallback.onSubsystemRestartOperationEnd();
+                        mCurrentRecoveryCallback = null;
+                    }
                 }, RESTART_TIMEOUT_MS);
             }
         });