kc3-lang/angle

2021-07-22T19:06:40

Fix Multithreaded eglDestroyContext()/eglTerminate() The following EGL calls can lead to a crash in eglMakeCurrent(): Thread A: eglMakeCurrent(context A) Thread B: eglDestroyContext(context A) B: eglTerminate() <<--- this release context A Thread A: eglMakeCurrent(context B) The eglMakeCurrent(context B) call will assert when attempting to unMakeCurrent(), since thread A doesn't know that context A was already destroyed by thread B. To fix this: 1.) A Context will only be released once there are no Threads that currently have a reference to it (no longer have the Context current). - Context::mIsCurrent is being removed, since it was inaccurate and not thread-safe. For example, when eglTerminate() was called, the eglTerminate()'ing-Thread would "steal" the Context that was current on another Thread to destroy it. 2.) A Display will only be fully terminated and its resources released once all Contexts have been destroyed and are no longer current. Otherwise, Display::terminate() will return if any Contexts are still in use by a Thread. EGL 1.5 Specification 3.2 Initialization If contexts or surfaces, created with respect to dpy are current (see section 3.7.3) to any thread, then they are not actually destroyed while they remain current. If other resources created with respect to dpy are in use by any current context or surface, then they are also not destroyed until the corresponding context or surface is no longer current. With this fix, the app com.netmarble.sknightsmmo can start. This also exposed an issue with GlslangFinalize(), since glslang can only be initialized/finalized once per process. Otherwise, the following EGL commands will call GlslangFinalize() without ever being able to GlslangInitialize() again, leading to crashes since GlslangFinalize() cleans up glslang for the entire process. dpy1 = eglGetPlatformDisplay() | eglInitialize(dpy1) | GlslangInitialize() dpy2 = eglGetPlatformDisplay() | eglInitialize(dpy2) | GlslangInitialize() eglTerminate(dpy2) | GlslangFinalize() eglInitialize(dpy1) | isInitialized() == true Since Display::isInitialized() == true, the rest of Display::initialize() is skipped and GlslangInitialize() is not called. Later, the next test that attempts to compile a program will crash due to glslang no longer being initialized. Finally, this exposed the following tests leaking EGLContext handles: - EGLSurfaceTest::initializeContext() - EGLContextSharingTest.DisplayShareGroupContextCreation - EGLCreateContextAttribsTest.IMGContextPriorityExtension - EGLMultiContextTest.TestContextDestroySimple Other tests were failing to reset the context, preventing the Display from being terminated since there were still references to Contexts owned by the display: eglMakeCurrent(dpy, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT); Bug: angleproject:6208 Bug: angleproject:6304 Bug: angleproject:6322 Test: EGLContextSharingTest.EglTerminateMultiThreaded Test: EGLContextSharingTestNoFixture.EglDestoryContextManyTimesSameContext Test: Load com.netmarble.sknightsmmo Change-Id: I160922af93db6cabe0ed396be77762fa8dfc7656 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3046961 Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Tim Van Patten <timvp@google.com>