(In reply to Alex Deucher from comment #15) > These patches may help: > http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20150928/302380.html > http://lists.freedesktop.org/archives/mesa-dev/2015-September/095718.html Afraid not, applied both of them and it still hangs. One interesting thing is that I was using mesa from the oibaf ppa which compiles against llvm 3.6. While using that I haven't been able to replay my apitrace of valley once - it always hangs before it finishes. However, I compiled mesa against llvm 3.7 (one compiled from source with the patch, and one from llvm's apt repository) and 3.8, and it gets much further now - I've been able to replay the trace three times without a hang, though it does ultimately hang unfortunately.