From 4a2d4ddf6ede7c5ccee353a4e0ada63a8cfd51dc Mon Sep 17 00:00:00 2001
From: Nate Myren <ntmyren@google.com>
Date: Fri, 13 Nov 2020 13:55:14 -0800
Subject: [PATCH] Fix potential deadlock in shutdown in HistoricalRegistry

Ensure that the memory lock is released before calling
persistPendingHistory in HistoricalRegistry.

Bug: 172776374
Test: none
Change-Id: I909de9f83cd43c695d0db99f82252ce36a0b972b
(cherry picked from commit 42387ceaedd6d6d53706e799486161db7fffcce5)
---
 .../java/com/android/server/appop/HistoricalRegistry.java   | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/services/core/java/com/android/server/appop/HistoricalRegistry.java b/services/core/java/com/android/server/appop/HistoricalRegistry.java
index 3d22a156b91c6..f49b5dca2b086 100644
--- a/services/core/java/com/android/server/appop/HistoricalRegistry.java
+++ b/services/core/java/com/android/server/appop/HistoricalRegistry.java
@@ -669,10 +669,12 @@ final class HistoricalRegistry {
 
     void shutdown() {
         synchronized (mInMemoryLock) {
-            if (mMode != AppOpsManager.HISTORICAL_MODE_DISABLED) {
-                persistPendingHistory();
+            if (mMode == AppOpsManager.HISTORICAL_MODE_DISABLED) {
+                return;
             }
         }
+        // Do not call persistPendingHistory inside the memory lock, due to possible deadlock
+        persistPendingHistory();
     }
 
     void persistPendingHistory() {