Update: Provide fallback should the locks on exit fail to catch and update function...

Update: Provide fallback should the locks on exit fail to catch and update function using pointer.

The previous commit 49a3d41d1c17734b0a8299b356f1e299386f4a42 removed the forced fallback to avoid potential race conditions.
The reason for having that fallback is to ensure that the exit process is guaranteed and not potentially blocked by a lock.

Provide an alternative that makes several attempts to properly lock on exit.
Only when those extra attempts fails should the failsafe/fallback be used.

Update controller_thread_process_cancel() to have the global data as a pointer.