Created attachment 486323 [details] testcase Tested inside VMWare Fusion. VMware SVGA 3D (Microsoft Corporation - WDDM) Driver version: 184.108.40.206
This callstack looks like a bug in VMWare's OpenGL implementation. It internally converts a number to a string and that crashes. We can't do anything about it. Incidentally, our framebufferRenderbuffer implementation is undergoing a rewrite, but that won't make a difference because we can't avoid calling glFramebufferRenderbuffer.
Ah, it is still possible that we are bitten by GL asynchronousness making the stack trace irrelevant. If you want to rule that possibility out, grab a debug build of firefox and run with MOZ_GL_DEBUG=1 firefox i.e. define the MOZ_GL_DEBUG environment variable to anything.
This is fixed since we started blacklisting other vendors than AMD/NVIDIA/Intel (so, all virtualization thingy^Wenvironments)