https://bugs.freedesktop.org/show_bug.cgi?id=90537
--- Comment #2 from Michel Dänzer michel@daenzer.net --- Created attachment 115936 --> https://bugs.freedesktop.org/attachment.cgi?id=115936&action=edit winsys/radeon: Unmap VA when destroying BO
I think this is most likely because we're not unmapping the virtual address range when closing a GEM handle.
Does this Mesa patch help? Note that you'll also need the kernel fixes in 4.0.3, or this patch will likely cause kernel hangs.