Bug Report

There seems to be a race condition in libco:

Here co_swap is a static function pointer, which is assigned to a bunch of data in co_swap_function that corresponds to assembly instructions before first use.

However this code assume that pointer assignment is regular, which is likely platform dependent. Better to use pthread_once rather than checking if its null.

This code should probably be using inline assembly macros instead of writing data to an unsigned char and interpreting it as a function, then they wouldn't have to worry about initializing things before first use in the first place.