The games in question are:
Batman Arkham Asylum GotY Edition
Batman Arkham City GotY Edition
Batman Arkham Origins

The lockups are kind of random but happen not long after playing one of the
games.
I have tried the nine tracker and CSMT with opengl. Both exhibit the problem.
I tried different kernel versions and also the andgpu-pro module and the lockup
always happens.
The lockups dont happen with Catalyst 15.12 and wine CSMT.

There is never anything in dmesg or the X.org log.

Hardware is:
001:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc.
[AMD/ATI] Amethyst XT [Radeon R9 M295X Mac Edition] [1002:6938] (rev f1)
        Subsystem: PC Partner Limited / Sapphire Technology Amethyst XT [Radeon
R9 M295X Mac Edition] [174b:e308]
        Kernel driver in use: amdgpu

I am using LLVM git and Mesa git.