MMU fault when tiled images are placed in system RAM
You can repro this with two GPUs and the NVK modifiers MR (mesa/mesa!28843 (closed)) and my NVK kernel branch (https://gitlab.freedesktop.org/gfxstrand/linux/-/commits/nvk/?ref_type=heads). All you have to do is run the compositor on one GPU and a Wayland Vulkan app (Sascha gears works) on the other. As long as the two GPUs are close enough in generation to share modifiers (so Turing+ or Volta-), you should get an instant MMU fault the moment we try to access the shared image. Personally, I've reproduced with Ampere+Ampere, Ampere+Turing, and Pascal+Kepler.