My application uses Lua in multithreaded environment with global mutex. It implemented like this:

1. Thread locks mutex,
2. Call lua_newthread
3. Perform some initialization on coroutine
4. Run lua_resume on coroutine
5. Unlocks mutex

lua_lock/unlock is not implemented, GC is stopped, when lua works with coroutine.

My question is, can I perform steps 2 and 3 without locking, if initialisation process does not requires any global Lua structs? Can i perform all this process without locking at all, if coroutine does not requires globals too?

In what case I generally can use Lua functions without locking?