commit 7d3dcb9235ec149af2f5139a8a9c6eac859d92e2
author Stephen Kiazyk <skiazyk@google.com> Wed Apr 05 16:46:49 2017 -0700
committer Stephen Kiazyk <skiazyk@google.com> Fri Apr 14 13:00:42 2017 -0700
tree eb501b420336da9075a29724cfa3937a222c4bed
parent 11c1acc33a7402153ab0e7308bc59921165819ab

Avoid a potential race condition on mDisplays

I've now run this on a HWC1 and HWC2 build. Both appear to be running
correctly.

Original Message:

The race could occur when transitioning in/out of VR flinger mode.
It is now avoided by ensuring that the primary |DisplayDevice| is always
created once |mStateLock| is released, and ensuring that all accesses
to the primary |DisplayDevice| are guarded by |mStateLock|.

Bug: 36194616
Bug: 37249613
Bug: 37288476

Test: Compiled, installed, and ran with both HWC1 and HWC2 variants.
  HWC1 was tested on Nexus 6P. Was able to boot, install apps, run apps,
  turn screen on/off, and reboot phone.
  HWC2 was tested on sailfish. Was able to boot, install apps, run apps,
  run VR apps using both N path, and O1 path, turn screen on/off, and
  reboot phone.

Change-Id: I0e80c2553f40cce2116b718bbb0d2566679f794a

services/surfaceflinger/DisplayHardware/HWComposer.cpp

diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.cpp b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
index 7314127..40979c9 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
@@ -206,7 +206,7 @@
         }
         disp = DisplayDevice::DISPLAY_EXTERNAL;
     }
-    mEventHandler->onHotplugReceived(disp,
+    mEventHandler->onHotplugReceived(this, disp,
             connected == HWC2::Connection::Connected);
 }
 

services/surfaceflinger/DisplayHardware/HWComposer.h

diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.h b/services/surfaceflinger/DisplayHardware/HWComposer.h
index 81f1619..78d0307 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.h
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.h
@@ -70,7 +70,7 @@
         friend class HWComposer;
         virtual void onVSyncReceived(
             HWComposer* composer, int32_t disp, nsecs_t timestamp) = 0;
-        virtual void onHotplugReceived(int32_t disp, bool connected) = 0;
+        virtual void onHotplugReceived(HWComposer* composer, int32_t disp, bool connected) = 0;
         virtual void onInvalidateReceived(HWComposer* composer) = 0;
     protected:
         virtual ~EventHandler() {}

services/surfaceflinger/DisplayHardware/HWComposer_hwc1.cpp

diff --git a/services/surfaceflinger/DisplayHardware/HWComposer_hwc1.cpp b/services/surfaceflinger/DisplayHardware/HWComposer_hwc1.cpp
index 5b5f1cf..dcb2913 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer_hwc1.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWComposer_hwc1.cpp
@@ -315,7 +315,7 @@
     queryDisplayProperties(disp);
     // Do not teardown or recreate the primary display
     if (disp != HWC_DISPLAY_PRIMARY) {
-        mEventHandler.onHotplugReceived(disp, bool(connected));
+        mEventHandler.onHotplugReceived(this, disp, bool(connected));
     }
 }
 

services/surfaceflinger/DisplayHardware/HWComposer_hwc1.h

diff --git a/services/surfaceflinger/DisplayHardware/HWComposer_hwc1.h b/services/surfaceflinger/DisplayHardware/HWComposer_hwc1.h
index f64d69a..4bc63bb 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer_hwc1.h
+++ b/services/surfaceflinger/DisplayHardware/HWComposer_hwc1.h
@@ -62,7 +62,7 @@
         friend class HWComposer;
         virtual void onVSyncReceived(
             HWComposer* composer, int32_t disp, nsecs_t timestamp) = 0;
-        virtual void onHotplugReceived(int disp, bool connected) = 0;
+        virtual void onHotplugReceived(HWComposer* composer, int disp, bool connected) = 0;
         virtual void onInvalidateReceived(HWComposer* composer) = 0;
     protected:
         virtual ~EventHandler() {}