modprobe: ERROR: could not insert 'v4l2loopback': Operation not permitted

[kuzdogan]

OS Version

Ubuntu 19.10

When I'm trying to run bash run.sh I see following errors:

Creating virtual camera /dev/video9 (sudo privelege required)
modprobe: ERROR: could not insert 'v4l2loopback': Operation not permitted
0: ./avatars/einstein.jpg
... #similar lines
7: ./avatars/schwarzenegger.png
load checkpoints..
cam_fomm.py:34: YAMLLoadWarning: calling yaml.load() without Loader=... is deprecated, as the default Loader is unsafe. Please read https://msg.pyyaml.org/load for full details.
  config = yaml.load(f)
--- Make sure the v4l2loopback kernel module is loaded ---
sudo modprobe v4l2loopback devices=1
Traceback (most recent call last):
  File "cam_fomm.py", line 230, in <module>
    stream = pyfakewebcam.FakeWebcam(f'/dev/video{opt.virt_cam}', frame.shape[1], frame.shape[0])
  File "/root/miniconda3/envs/avatarify/lib/python3.8/site-packages/pyfakewebcam/pyfakewebcam.py", line 31, in __init__
    raise FileNotFoundError('device does not exist: {}'.format(video_device))
FileNotFoundError: device does not exist: /dev/video9

I am not familiar with conda environments so maybe it could be the problem. On terminal I see it's running the base environment:

(base) kuzdogan@kuzdogan-UX331UN

Another thing to notice is I can only run bash run.sh as a root user so after sudo -i. If I run sudo bash run.sh I get

run.sh: line 9: conda: command not found
run.sh: line 9: /etc/profile.d/conda.sh: No such file or directory
run.sh: line 10: conda: command not found

Thank you

[alievk]

Normally you don't have to run run.sh as sudo, it will ask you sudo pass for loading v4l2loopback kernel module. Does this happen?

[potassium-chloride]

I have the same problem in Cinnamon 19.3 (kernel: 5.3.0-46-generic). I catched #37 and tried to solve it. install.sh cloned and made v4l2loopback driver successfully but module was not signed.

I tried sudo echo x > /proc/sysrq-trigger but it has no effect and dmesg said:

[236654.822141] Lockdown: modprobe: Loading of unsigned module is restricted; see man kernel_lockdown.7
[237401.229309] sysrq: HELP : loglevel(0-9) reboot(b) crash(c) terminate-all-tasks(e) memory-full-oom-kill(f) kill-all-tasks(i) thaw-filesystems(j) sak(k) show-backtrace-all-active-cpus(l) show-memory-usage(m) nice-all-RT-tasks(n) poweroff(o) show-registers(p) show-all-timers(q) unraw(r) sync(s) show-task-states(t) unmount(u) force-fb(V) show-blocked-tasks(w) dump-ftrace-buffer(z) 
[239238.910641] sysrq: HELP : loglevel(0-9) reboot(b) crash(c) terminate-all-tasks(e) memory-full-oom-kill(f) kill-all-tasks(i) thaw-filesystems(j) sak(k) show-backtrace-all-active-cpus(l) show-memory-usage(m) nice-all-RT-tasks(n) poweroff(o) show-registers(p) show-all-timers(q) unraw(r) sync(s) show-task-states(t) unmount(u) force-fb(V) show-blocked-tasks(w) dump-ftrace-buffer(z)

I don't want to recompile my kernel

[kuzdogan]

@alievk yes I am getting exactly the same error

[SSantiagoDev]

same issue here

[alievk]

This may be relevant https://github.com/xairy/unlockdown#method-0-sysrq-trigger

[potassium-chloride]

@alievk this method equivalents sudo echo x > /proc/sysrq-trigger and causes same effect (help line in dmesg). This problem is related to security boot and security police in last versions of Linux Kernel. Module should be signed. I think the true way would be to ask the v4l2loopback developers about this and publish signed v4l2loopback module