i most recently had a radeon fence lockup on netbsd-8. spz@ has a regularly full lock-up scrolling in firefox, but i haven't seen that one myself.
ie, i'm not sure that this is netbsd-9 directly, though it maybe that there is a new bug for your specific gpu. what you can do, at least, is gather back traces for the various threads by using crash(8) etc, and sending those as a PR. thanks. .mrg.
