dm_control: mujoco.FatalError: Offscreen framebuffer is not complete, error 0x8cdd

Here is a complete self-contained snippet that, for me, consistently errors with mujoco.FatalError: Offscreen framebuffer is not complete, error 0x8cdd

from multiprocessing import Process

from dm_control import composer
from dm_control.locomotion.walkers.cmu_humanoid import CMUHumanoid
from dm_control.locomotion.arenas import floors

class Task(composer.Task):
    
    def __init__(self):
        self._arena = floors.Floor()
        self._walker = CMUHumanoid(
            observable_options={'egocentric_camera': {'enabled': True}})
        spawn_site = self._arena.mjcf_model.worldbody.add('site')
        self._walker.create_root_joints(
            self._arena.attach(self._walker, spawn_site))
        spawn_site.remove()

    @property
    def root_entity(self):
        return self._arena

    def get_reward(self, physics):
        return 1.

_ = composer.Environment(task=Task())  # Won't error without this line?!?

def foo():
    env = composer.Environment(task=Task())

p = Process(target=foo)
p.start()  # Errors here.

Thank you @vaxenburg for sharing the script to reproduce the problem. In this particular case, I suspect that this is caused by the first call

_ = composer.Environment(task=Task())  # Won't error without this line?!?

initialized some EGL resources, while

p = Process(target=foo)

inherit the resources (which it shouldn’t) as a subprocess (because by default python forks). When the subprocess start to initialize EGL again, something bad happened.

I was able to get rid of the issue in your particular case, by switching start method of multiprocessing to spawn,

import multiprocessing

from multiprocessing import Process

from dm_control import composer
from dm_control.locomotion.walkers.cmu_humanoid import CMUHumanoid
from dm_control.locomotion.arenas import floors


class Task(composer.Task):

    def __init__(self):
        self._arena = floors.Floor()
        self._walker = CMUHumanoid(
            observable_options={'egocentric_camera': {
                'enabled': True
            }})
        spawn_site = self._arena.mjcf_model.worldbody.add('site')
        self._walker.create_root_joints(
            self._arena.attach(self._walker, spawn_site))
        spawn_site.remove()

    @property
    def root_entity(self):
        return self._arena

    def get_reward(self, physics):
        return 1.


def foo():
    env = composer.Environment(task=Task())


if __name__ == "__main__":
    multiprocessing.set_start_method("spawn")

    _ = composer.Environment(task=Task())  # Won't error without this line?!?

    p = Process(target=foo)
    p.start()

Here is a complete self-contained snippet that, for me, consistently errors with mujoco.FatalError: Offscreen framebuffer is not complete, error 0x8cdd

from multiprocessing import Process

from dm_control import composer
from dm_control.locomotion.walkers.cmu_humanoid import CMUHumanoid
from dm_control.locomotion.arenas import floors

class Task(composer.Task):
    
    def __init__(self):
        self._arena = floors.Floor()
        self._walker = CMUHumanoid(
            observable_options={'egocentric_camera': {'enabled': True}})
        spawn_site = self._arena.mjcf_model.worldbody.add('site')
        self._walker.create_root_joints(
            self._arena.attach(self._walker, spawn_site))
        spawn_site.remove()

    @property
    def root_entity(self):
        return self._arena

    def get_reward(self, physics):
        return 1.

_ = composer.Environment(task=Task())  # Won't error without this line?!?

def foo():
    env = composer.Environment(task=Task())

p = Process(target=foo)
p.start()  # Errors here.

This one, on all machines: | NVIDIA-SMI 525.60.13 Driver Version: 525.60.13 CUDA Version: 12.0 |

No updates on my end. I’m still having this problem…