I don't have a i915 test system handy.

This doesn't happen with llvmpipe.

I've reviewed fd33a6bcd7f1271e80332379131e82e00fe10586 once again, and it looks
alright -- I don't spot anything wrong -- it really should lead to pretty much
the same code.

The crash too, is quite peculiar: i915 has no threading, so I don't see how
this would change anything.

Could you double check this crash is not random?