emacs-lock-locked-buffer-functions is a variable defined in `emacs-lock.el'.
Its value is

  • This variable may be risky if used as a file-local variable.

Abnormal hook run when Emacs Lock prevents exiting Emacs, or killing a buffer.
The functions get one argument, the first locked buffer found.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.3 of Emacs.