From fe322bdca3bfc2c42ffd477109ff815d45339058 Mon Sep 17 00:00:00 2001
From: Yi Jiang <eejiang@google.com>
Date: Mon, 24 May 2021 14:54:50 -0700
Subject: [PATCH] Ensures RotationRequest#mLock can only accquried by main
 thread.

There are 2 locks in RRMS and RotationRequest class. UI thread and main
thread both needs to acquire these lock which introduce risk of
deadlocking.

This change fixes the issue by only letting the main thread get the lock of
RotationRequest.

Test: presubmit
Bug: 188932757
Change-Id: I8fd0beb094356636096155eabeef8c9d24fa0da1
---
 .../RemoteRotationResolverService.java                 | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/services/core/java/com/android/server/rotationresolver/RemoteRotationResolverService.java b/services/core/java/com/android/server/rotationresolver/RemoteRotationResolverService.java
index 35aff8dc70ce6..a58291425d4c7 100644
--- a/services/core/java/com/android/server/rotationresolver/RemoteRotationResolverService.java
+++ b/services/core/java/com/android/server/rotationresolver/RemoteRotationResolverService.java
@@ -126,14 +126,12 @@ class RemoteRotationResolverService extends ServiceConnector.Impl<IRotationResol
 
 
         void cancelInternal() {
-            synchronized (mLock) {
-                if (mIsFulfilled) {
-                    return;
-                }
-                mIsFulfilled = true;
-            }
             Handler.getMain().post(() -> {
                 synchronized (mLock) {
+                    if (mIsFulfilled) {
+                        return;
+                    }
+                    mIsFulfilled = true;
                     try {
                         if (mCancellation != null) {
                             mCancellation.cancel();