From d4393b28978e45f67ace6530338c01ef647fada6 Mon Sep 17 00:00:00 2001
From: Robert Carr <racarr@google.com>
Date: Tue, 26 Jan 2016 00:18:42 -0800
Subject: Fix reentrant deadlock in GLSurfaceView.

It is possible for clients to call SurfaceView
methods e.g. setFormat from the GLSurfaceView#Renderer
drawFrame callback. In this case, SurfaceView#updatewindow
will understand that a redraw is required, and will request
it back to GLSurfaceView. Remember, we are still on the GLThread
though (from the drawFrame callback). So these methods
(requestRenderAndWait, windowSizeChanged), need to be reentrant.
Also fix a data race around mWantRenderNotification, which was
accessed out of lock.

Bug: 26770615
Change-Id: Ic66a36c886ae0b085dd456a4220f0d4f270fb016
---
 opengl/java/android/opengl/GLSurfaceView.java | 29 +++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

(limited to 'opengl')

diff --git a/opengl/java/android/opengl/GLSurfaceView.java b/opengl/java/android/opengl/GLSurfaceView.java
index 9c01f4f4d7a2..f37ec58fbe26 100644
--- a/opengl/java/android/opengl/GLSurfaceView.java
+++ b/opengl/java/android/opengl/GLSurfaceView.java
@@ -1291,6 +1291,7 @@ public class GLSurfaceView extends SurfaceView implements SurfaceHolder.Callback
                 boolean createGlInterface = false;
                 boolean lostEglContext = false;
                 boolean sizeChanged = false;
+                boolean wantRenderNotification = false;
                 boolean doRenderNotification = false;
                 boolean askedToReleaseEglContext = false;
                 int w = 0;
@@ -1448,6 +1449,9 @@ public class GLSurfaceView extends SurfaceView implements SurfaceHolder.Callback
                                     }
                                     mRequestRender = false;
                                     sGLThreadManager.notifyAll();
+                                    if (mWantRenderNotification) {
+                                        wantRenderNotification = true;
+                                    }
                                     break;
                                 }
                             }
@@ -1574,8 +1578,9 @@ public class GLSurfaceView extends SurfaceView implements SurfaceHolder.Callback
                             break;
                     }
 
-                    if (mWantRenderNotification) {
+                    if (wantRenderNotification) {
                         doRenderNotification = true;
+                        wantRenderNotification = false;
                     }
                 }
 
@@ -1625,11 +1630,21 @@ public class GLSurfaceView extends SurfaceView implements SurfaceHolder.Callback
 
         public void requestRenderAndWait() {
             synchronized(sGLThreadManager) {
+                // If we are already on the GL thread, this means a client callback
+                // has caused reentrancy, for example via updating the SurfaceView parameters.
+                // We will return to the client rendering code, so here we don't need to
+                // do anything.
+                if (Thread.currentThread() == this) {
+                    return;
+                }
+
                 mWantRenderNotification = true;
                 mRequestRender = true;
                 mRenderComplete = false;
+
                 sGLThreadManager.notifyAll();
-                while (!mExited && !mPaused && mRenderComplete == false) {
+
+                while (!mExited && !mPaused && !mRenderComplete && ableToDraw()) {
                     try {
                         sGLThreadManager.wait();
                     } catch (InterruptedException ex) {
@@ -1726,6 +1741,16 @@ public class GLSurfaceView extends SurfaceView implements SurfaceHolder.Callback
                 mSizeChanged = true;
                 mRequestRender = true;
                 mRenderComplete = false;
+
+                // If we are already on the GL thread, this means a client callback
+                // has caused reentrancy, for example via updating the SurfaceView parameters.
+                // We need to process the size change eventually though and update our EGLSurface.
+                // So we set the parameters and return so they can be processed on our
+                // next iteration.
+                if (Thread.currentThread() == this) {
+                    return;
+                }
+
                 sGLThreadManager.notifyAll();
 
                 // Wait for thread to react to resize and render a frame
-- 
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