Avoid a potential race condition on mDisplays
Update: The HWC1 path needed to be updated in light of a change to
SurfaceFlinger.h. The build now works for both paths.
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
Test: Compiled for both HWC1 and HWC2 surface flinger builds.
Normal behavior is unchanged. Explicitly testing the race
condition required instrumenting code with sleep statements.
Change-Id: I0b00e857a3b2fd01948a888db2f0715d2a8204c1
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 46121cf..219d662 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -184,8 +184,9 @@
void repaintEverything();
// returns the default Display
- sp<const DisplayDevice> getDefaultDisplayDevice() const {
- return getDisplayDevice(mBuiltinDisplays[DisplayDevice::DISPLAY_PRIMARY]);
+ sp<const DisplayDevice> getDefaultDisplayDevice() {
+ Mutex::Autolock _l(mStateLock);
+ return getDefaultDisplayDeviceLocked();
}
// utility function to delete a texture on the main thread
@@ -304,7 +305,7 @@
* HWComposer::EventHandler interface
*/
virtual void onVSyncReceived(HWComposer* composer, int type, nsecs_t timestamp);
- virtual void onHotplugReceived(int disp, bool connected);
+ virtual void onHotplugReceived(HWComposer* composer, int disp, bool connected);
virtual void onInvalidateReceived(HWComposer* composer);
/* ------------------------------------------------------------------------
@@ -439,6 +440,12 @@
return mDisplays.valueFor(dpy);
}
+ sp<const DisplayDevice> getDefaultDisplayDeviceLocked() const {
+ return getDisplayDevice(mBuiltinDisplays[DisplayDevice::DISPLAY_PRIMARY]);
+ }
+
+ void createDefaultDisplayDevice();
+
int32_t getDisplayType(const sp<IBinder>& display) {
if (!display.get()) return NAME_NOT_FOUND;
for (int i = 0; i < DisplayDevice::NUM_BUILTIN_DISPLAY_TYPES; ++i) {