Just done some tests:

enable_scheduler=0, enable_semaphores=1, vm_fault_stop=0, vm_debug=1
Hang after a few  minutes, normal desktop use or running the valley test. Many
VM faults in dmesg.

enable_scheduler=0, enable_semaphores=0, vm_fault_stop=1, vm_debug=1
Hang after a few  minutes, normal desktop use or running the valley test. Only
one VM fault visible in dmesg, that would be due to vm_fault_stop=1 I'm
guessing?

enable_scheduler=0, enable_semaphores=0, vm_fault_stop=0, vm_debug=1
Same as above, but with several VM faults in dmesg.

enable_scheduler=1, enable_semaphores=0, vm_fault_stop=0, vm_debug=1
All good.