From Dave Airlie:
I've just posted a patch to fix that to dri-devel, can you check it fixes your issue?
"drm/radeon/kms: drop lock in return path of radeon_fence_count_emitted" fixes the problem. Tested on top of 47492a23a and 3.3.0-rc3+00188-g3ec1e88.
Thanks,
Mikko