GRAPHICS: OpenGL::Framebuffer::deactivate crash with gui_return_to_launcher_at_exit

[dwatteau]

This is with ScummVM 2.7.0git-c93d460ee24 on OSX 10.4/10.5 PPC. Investigating a bit, I don't think this is port-related or game-related, and that the issue is somewhere in the graphics backend, but I may be wrong, so adjust this if necessary.

On this setup, if I:

1. Enable gui_return_to_launcher_at_exit
2. Start the demo of Grim Fandango
3. Exit it (once the first scene is fully loaded) in order to go back to the launcher

then ScummVM always crashes with the following backtrace:

WARNING: Libretro is not supported!
Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_PROTECTION_FAILURE at address: 0x0000000c
0x0026a6c8 in OpenGL::Framebuffer::deactivate (this=<incomplete type>) at ./backends/graphics/opengl/framebuffer.h:159
159	class Backbuffer : public Framebuffer {

(gdb) bt
#0  0x0026a6c8 in OpenGL::Framebuffer::deactivate (this=<incomplete type>) at ./backends/graphics/opengl/framebuffer.h:159
#1  0x0027aa00 in OpenGL::Pipeline::deactivateInternal (this=0x8a13fa0) at ./backends/graphics/opengl/pipelines/pipeline.h:153
#2  0x0028b0f4 in OpenGL::ShaderPipeline::deactivateInternal (this=0x8a13fa0) at ./common/hashmap.h:92
#3  0x0027a9a4 in OpenGL::Pipeline::deactivate (this=0x8a13fa0) at ./backends/graphics/opengl/pipelines/pipeline.h:153
#4  0x0027a8a0 in OpenGL::Pipeline::activate (this=0x8a4a540) at ./backends/graphics/opengl/pipelines/pipeline.h:153
#5  0x0026e354 in OpenGL::OpenGLGraphicsManager::updateScreen (this=0x2858400) at ./backends/graphics/opengl/framebuffer.h:159
#6  0x002a8ac0 in OpenGLSdlGraphicsManager::updateScreen (this=0x2858400) at ./common/func.h:71
#7  0x0024b1dc in ModularGraphicsBackend::updateScreen (this=0x233f018) at ./common/base-str.h:173
#8  0x001b6a1c in GUI::GuiManager::screenChange (this=<incomplete type>) at ./common/ptr.h:299
#9  0x001b68e0 in GUI::GuiManager::checkScreenChange (this=<incomplete type>) at ./common/ptr.h:299
#10 0x001a8118 in GUI::Dialog::Dialog (this=<incomplete type>, name=<incomplete type>) at ./gui/dialog.h:49
#11 0x001b948c in GUI::LauncherDialog::LauncherDialog (this=0x29e0600, dialogName=<incomplete type>, chooser=0xbfffcb48) at ./common/memorypool.h:148

(more GDB output attached below; note that this port has a very limited GDB and so its output is just a rough indication)

With some more manual debugging, it looks like the crash appears when pipeline.cpp:Pipeline::deactivateInternal() calls _activeFramebuffer->deactivate() and then framebuffer.cpp:Framebuffer::deactivate() calls deactivateInternal() which crashes.

This wouldn't happen with ScummVM 2.6.1 on the same setup. 2D games are fine, even when rendering them with OpenGL.

configure enabled the following GL-related features:

config.h:#define USE_GLES_MODE 0
config.h:#define USE_OPENGL
config.h:#define USE_GLAD
config.h:#define USE_OPENGL_GAME
config.h:#define USE_OPENGL_SHADERS

config.mk:USE_OPENGL = 1
config.mk:USE_GLAD = 1
config.mk:USE_OPENGL_GAME = 1
config.mk:USE_OPENGL_SHADERS = 1

and I'm including some OpenGL debug below too.

If I disable the gui_return_to_launcher_at_exit feature there, I'm not seeing any crash.

[dwatteau]

GDB backtrace when returning to launcher

[dwatteau]

ScummVM -d6 OpenGL output when returning to launcher on this setup

[lephilousophe]

This is fixed by 4a7d75595dd8eb0800d0a67e5ebb9c35c10a45a4 in master and 597c17363ebd4c79cf7c1fcad0242cc14db124f1 in 2.7 branch.