Subject: bug#23013: 25.0.92; assertion failure on marker outside text range in echo area

From: Eli Zaretskii <[email-masked]>
Date: Tue, 15 Mar 2016 21:14:54 +0200

> From: Ken Raeburn <[email-masked]>
> Date: Tue, 15 Mar 2016 15:00:34 -0400
> 
> 
> I had several X11 frames open, most local and one remote. In a local
> window I was invoking this function, which kills a set of buffers based
> on their file names:
> 
>   (defun kill-buffers-under (dir)
>     (interactive "GKill buffers under directory: ")
>     (setq dir (file-name-as-directory (expand-file-name dir)))
>     (mapc (lambda (b)
>             (let ((file-name (buffer-file-name b)))
>               (if (and file-name
>                        (same-or-parent-dir-p (file-name-directory file-name)
>                                              dir))
>                   (kill-buffer b))))
>           (buffer-list)))
> 
> I entered the directory name in the minibuffer, after I hit return,
> Emacs crashed. Once again, redisplay_window is calling marker_position,
> on a marker with position 9 in an empty echo-area buffer.

Could it be that one of the buffers you killed was an echo-area
buffer?