From 2076f35549c7c04035b9f626d9209e049b6c91f8 Mon Sep 17 00:00:00 2001
From: Jamie Gennis <jgennis@google.com>
Date: Sun, 30 Jan 2011 15:59:36 -0800
Subject: [PATCH] Fix a multithreading bug in libagl's EGL.

The bug caused libagl to return 0 from eglGetError if an EGL error value
(including EGL_SUCCESS) was set on a different thread but not yet on the
current thread.

Bug: 3403756
Change-Id: Ifd965091d116745c2e22c121151ade9e78eb14c6
---
 opengl/libagl/egl.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/opengl/libagl/egl.cpp b/opengl/libagl/egl.cpp
index 7ac6f9277..a1cb23a25 100644
--- a/opengl/libagl/egl.cpp
+++ b/opengl/libagl/egl.cpp
@@ -82,6 +82,11 @@ static GLint getError() {
     if (ggl_unlikely(gEGLErrorKey == -1))
         return EGL_SUCCESS;
     GLint error = (GLint)pthread_getspecific(gEGLErrorKey);
+    if (error == 0) {
+        // The TLS key has been created by another thread, but the value for
+        // this thread has not been initialized.
+        return EGL_SUCCESS;
+    }
     pthread_setspecific(gEGLErrorKey, (void*)EGL_SUCCESS);
     return error;
 }