Subject: bug#23445: 24.5; freeze in sh mode with show-paren-mode

From: Vincent Lefevre <[email-masked]>
Date: Wed, 04 May 2016 14:07:16 +0200

On a Debian/unstable machine:

1. Run: emacs -Q --eval '(show-paren-mode 1)' does-not-exist.sh
2. Type "if", then <left>.

The cursor moves over the "f" and Emacs is frozen, with 100% CPU usage.

* If Emacs has its own graphic window, then even Ctrl-C in the terminal
  from which Emacs has been started does not quit it. One needs to type
  C-g three times in the Emacs window.

* If Emacs runs in a terminal emulator (e.g. with -nw), then a first C-g
  has no effects and a second C-g suspends Emacs (TSTP signal).

In GNU Emacs 24.5.1 (x86_64-pc-linux-gnu, GTK+ Version 3.18.9)
 of 2016-04-08 on binet, modified by Debian
Windowing system distributor `The X.Org Foundation', version 11.0.11803000
System Description:	Debian GNU/Linux 7.10 (wheezy)

Configured using:
 `configure --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/lib
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes
 --enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.5/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.5/site-lisp:/usr/share/emacs/site-lisp
 --build x86_64-linux-gnu --prefix=/usr --sharedstatedir=/var/lib
 --libexecdir=/usr/lib --localstatedir=/var/lib
 --infodir=/usr/share/info --mandir=/usr/share/man --with-pop=yes
 --enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.5/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.5/site-lisp:/usr/share/emacs/site-lisp
 --with-x=yes --with-x-toolkit=gtk3 --with-toolkit-scroll-bars
 'CFLAGS=-g -O2 -fstack-protector-strong -Wformat
 -Werror=format-security -Wall' 'CPPFLAGS=-Wdate-time
 -D_FORTIFY_SOURCE=2' LDFLAGS=-Wl,-z,relro'

Important settings:
  value of $LC_COLLATE: POSIX
  value of $LC_CTYPE: en_US.UTF-8
  value of $LC_TIME: en_DK
  value of $LANG: POSIX
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  display-time-mode: t
  show-paren-mode: t
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
Loading /etc/emacs/site-start.d/50latex-cjk-common.el (source)...
Loading cjk-enc...done
Loading /etc/emacs/site-start.d/50latex-cjk-common.el (source)...done
Loading /etc/emacs/site-start.d/50latex-cjk-thai.el (source)...done
Loading /etc/emacs/site-start.d/50psvn.el (source)...done
Loading /etc/emacs/site-start.d/50texlive-lang-english.el (source)...done
Loading /etc/emacs/site-start.d/50w3m-el.el (source)...done
Loading /home/vlefevre/share/emacs/site-lisp/mutteditor.el (source)...done
Loading time...done
For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:
/usr/share/emacs24/site-lisp/cmake-data/cmake-mode hides /usr/share/emacs/site-lisp/cmake-mode
/usr/share/emacs/24.5/site-lisp/debian-startup hides /usr/share/emacs/site-lisp/debian-startup
/usr/share/emacs24/site-lisp/flim/md4 hides /usr/share/emacs/24.5/lisp/md4
/usr/share/emacs24/site-lisp/flim/hex-util hides /usr/share/emacs/24.5/lisp/hex-util
/usr/share/emacs24/site-lisp/flim/sasl-cram hides /usr/share/emacs/24.5/lisp/net/sasl-cram
/usr/share/emacs24/site-lisp/flim/hmac-md5 hides /usr/share/emacs/24.5/lisp/net/hmac-md5
/usr/share/emacs24/site-lisp/flim/hmac-def hides /usr/share/emacs/24.5/lisp/net/hmac-def
/usr/share/emacs24/site-lisp/flim/sasl-digest hides /usr/share/emacs/24.5/lisp/net/sasl-digest
/usr/share/emacs24/site-lisp/flim/sasl hides /usr/share/emacs/24.5/lisp/net/sasl
/usr/share/emacs24/site-lisp/flim/sasl-ntlm hides /usr/share/emacs/24.5/lisp/net/sasl-ntlm
/usr/share/emacs24/site-lisp/flim/ntlm hides /usr/share/emacs/24.5/lisp/net/ntlm
/usr/share/emacs24/site-lisp/latex-cjk-thai/thai-word hides /usr/share/emacs/24.5/lisp/language/thai-word

Features:
(shadow sort gnus-util mail-extr warnings emacsbug message format-spec
rfc822 mml easymenu mml-sec mm-decode mm-bodies mm-encode mail-parse
rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045
ietf-drums mm-util help-fns mail-prsvr mail-utils time cus-start
cus-load paren cc-styles cc-align cc-engine cc-vars cc-defs edmacro
kmacro cl-loaddefs cl-lib w3m-load time-date tooltip electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel x-win x-dnd tool-bar dnd
fontset image regexp-opt fringe tabulated-list newcomment lisp-mode
prog-mode register page menu-bar rfn-eshadow timer select scroll-bar
mouse jit-lock font-lock syntax facemenu font-core frame cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev
minibuffer nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
dbusbind gfilenotify dynamic-setting system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty emacs)

Memory information:
((conses 16 92952 8686)
 (symbols 48 20466 0)
 (miscs 40 46 118)
 (strings 32 16225 5134)
 (string-bytes 1 484972)
 (vectors 16 10284)
 (vector-slots 8 395496 4706)
 (floats 8 70 243)
 (intervals 56 231 0)
 (buffers 960 12)
 (heap 1024 25406 963))