From 489b25e7e94cd15ea1867ae73ba3bc75bce76428 Mon Sep 17 00:00:00 2001
From: Fiona Campbell <flc@google.com>
Date: Thu, 9 Sep 2021 17:10:52 +0000
Subject: [PATCH] Fix NPE when passing displayId through handler

NPE was thrown when calling getPendingFrameRateOverrideUids. This is
because the LogicalDisplay array could change before the message is
handled. This fix ensures that the logical display is valid before
continuing with the method.

Bug: 198359227
Bug: 198159201
Bug: 199027886

Test: Verify it doesn't crash
Change-Id: I11adf67478d7a6f81512aa3cd4bc568056dfa80a
---
 .../java/com/android/server/display/DisplayManagerService.java | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/services/core/java/com/android/server/display/DisplayManagerService.java b/services/core/java/com/android/server/display/DisplayManagerService.java
index 73bcea6de115f..827523be0d3ab 100644
--- a/services/core/java/com/android/server/display/DisplayManagerService.java
+++ b/services/core/java/com/android/server/display/DisplayManagerService.java
@@ -2252,6 +2252,9 @@ public final class DisplayManagerService extends SystemService {
                         int displayId = msg.arg1;
                         final LogicalDisplay display =
                                 mLogicalDisplayMapper.getDisplayLocked(displayId);
+                        if (display == null) {
+                            break;
+                        }
                         uids = display.getPendingFrameRateOverrideUids();
                         display.clearPendingFrameRateOverrideUids();
                     }