Bug 102574

Summary: glDrawBuffer crashes in case of surfaceless context
Product: Mesa Reporter: Volker Vogelhuber <v.vogelhuber>
Component: Drivers/DRI/i915Assignee: Default DRI bug account <dri-devel>
Status: RESOLVED MOVED QA Contact: Default DRI bug account <dri-devel>
Severity: normal    
Priority: medium    
Version: 17.1   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:

Description Volker Vogelhuber 2017-09-07 07:03:26 UTC 
I've created a surfaceless OpenGL context using the EGL_KHR_surfaceless_context extension together with eglGetPlatformDisplay/EGL_PLATFORM_GBM_MESA.
In this scenario there seem to be no valid default framebuffer which is Ok, as I'm normally only render to FBOs with textures bound. Due to an error on my side I called glDrawBuffer with GL_FRONT_LEFT while no FBO was bound.

This result in a crash in intel_buffers.c because in intelDrawBuffer()
dri2InvalidateDrawable is called with a null pointer which is
not checked in dri2InvalidateDrawable() or anywhere before.

While the root cause for triggering the error is on my side,
I think it may be better to raise an error instead of crashing.
So I propose to add a check to brw->driContext->driDrawablePriv
within intelDrawBuffer. Probably if the driDrawablePriv is nullptr
one should not call intel_prepare_render either. 

Mesa 17.1 with Kernel 4.9.6 on Intel Apollo Lake GPU
Comment 1 GitLab Migration User 2019-09-18 19:40:24 UTC 
-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/mesa/mesa/issues/778.

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.