My application uses Lua in multithreaded environment with global mutex. It implemented like this: Thread locks mutex, Call lua_newthread Perform some initialization on coroutine Run lua_resume on coroutine 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?