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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - glDrawBuffer crashes in case of surfaceless context"
href="https://bugs.freedesktop.org/show_bug.cgi?id=102574">102574</a>
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<th>Summary</th>
<td>glDrawBuffer crashes in case of surfaceless context
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<th>Product</th>
<td>Mesa
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<th>Version</th>
<td>17.1
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<th>Hardware</th>
<td>x86-64 (AMD64)
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<th>OS</th>
<td>Linux (All)
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>medium
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<th>Component</th>
<td>Drivers/DRI/i915
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<th>Assignee</th>
<td>dri-devel@lists.freedesktop.org
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<th>Reporter</th>
<td>v.vogelhuber@digitalendoscopy.de
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<th>QA Contact</th>
<td>dri-devel@lists.freedesktop.org
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<div>
<pre>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</pre>
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