From 209500045607e6a7d363ee5c1010478a058c3e0a Mon Sep 17 00:00:00 2001
From: Dan Stoza <stoza@google.com>
Date: Thu, 18 Jun 2020 14:56:58 -0700
Subject: SF: Guard Power HAL access with lock

Adds a lock around Power HAL access to prevent concurrent access from
multiple binder threads.

Bug: 158270361
Test: build, boot
Change-Id: I7262cdb8addf72ef0657f5b9394e1ba324e3e43f
---
 services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp | 2 ++
 services/surfaceflinger/DisplayHardware/PowerAdvisor.h   | 7 +++++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp b/services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp
index 1d8179c9ac..4b4c050f8e 100644
--- a/services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp
+++ b/services/surfaceflinger/DisplayHardware/PowerAdvisor.cpp
@@ -85,6 +85,7 @@ void PowerAdvisor::setExpensiveRenderingExpected(DisplayId displayId, bool expec
 
     const bool expectsExpensiveRendering = !mExpensiveDisplays.empty();
     if (mNotifiedExpensiveRendering != expectsExpensiveRendering) {
+        std::lock_guard lock(mPowerHalMutex);
         HalWrapper* const halWrapper = getPowerHal();
         if (halWrapper == nullptr) {
             return;
@@ -108,6 +109,7 @@ void PowerAdvisor::notifyDisplayUpdateImminent() {
     }
 
     if (mSendUpdateImminent.load()) {
+        std::lock_guard lock(mPowerHalMutex);
         HalWrapper* const halWrapper = getPowerHal();
         if (halWrapper == nullptr) {
             return;
diff --git a/services/surfaceflinger/DisplayHardware/PowerAdvisor.h b/services/surfaceflinger/DisplayHardware/PowerAdvisor.h
index 34e63e725b..95eb0e2bb7 100644
--- a/services/surfaceflinger/DisplayHardware/PowerAdvisor.h
+++ b/services/surfaceflinger/DisplayHardware/PowerAdvisor.h
@@ -19,6 +19,8 @@
 #include <atomic>
 #include <unordered_set>
 
+#include <utils/Mutex.h>
+
 #include "../Scheduler/OneShotTimer.h"
 #include "DisplayIdentification.h"
 
@@ -56,10 +58,11 @@ public:
     void notifyDisplayUpdateImminent() override;
 
 private:
-    HalWrapper* getPowerHal();
+    HalWrapper* getPowerHal() REQUIRES(mPowerHalMutex);
+    bool mReconnectPowerHal GUARDED_BY(mPowerHalMutex) = false;
+    std::mutex mPowerHalMutex;
 
     std::atomic_bool mBootFinished = false;
-    bool mReconnectPowerHal = false;
 
     std::unordered_set<DisplayId> mExpensiveDisplays;
     bool mNotifiedExpensiveRendering = false;
-- 
cgit v1.2.3-59-g8ed1b