Subject: bug#19191: 24.4; su command in *shell* buffer does not work

From: Eli Zaretskii <[email-masked]>
Date: Mon, 30 Mar 2015 20:22:24 +0300

> From: 白井彰 <[email-masked]>
> Date: Tue, 31 Mar 2015 02:08:51 +0900
> Cc: Akira Shirai <[email-masked]>
> 
> "su: Sorry" also occurs on emacs-24.5-rc1.

You need to find out why the shell's TTY is not a PTY device on your
system.  As Andreas pointed out, this is the reason for the problem.