Whenever I open a file which contains font awesome 5 icons in it, or I paste a icon into emacs buffer, emacs will freeze forever.
After researching for an afternoon, I found that as long as I don't customize emacs default font (by putting (add-to-list 'default-frame-alist '(font . "NovaMono-12")) in my emacs config file), it will work fine.
Alse, using emacs with -nw flag can display the icons normally too.