bug#21833: 24.4; desktop-kill, which is interactive, is in kill-emacs-hook

[Glenn Morris]

The point is, kill-emacs-hook can run in situations where it is
impossible for Emacs to interact with the user.
Any yes-or-no-p questions will never be answered.
Emacs will hang and have to be forcibly killed.
Exactly as it says in the OP.

So don't put anything on kill-emacs-hook that needs an interactive
response from the user. Decide on a sensible non-interactive behaviour,
and for the interactive case use kill-emacs-query-functions.
The documentation seems clear to me.