bug#27036: 25.1; Blocking call to accept-process-output with quit inhibited!!

[Francesco Potortì]

I use inferior-octave-mode, where the Octave interpreter runs in a
buffer, similarly to shell-mode.

Starting somewhere later than Emacs 22, this mode makes on-the-fly
syntax suggestions whenever point is at a function definition or
similar.

Apparently something goes wrong with this funcitonality, or so I
suspect.  I get error messages about

  Blocking call to accept-process-output with quit inhibited!!

and even when this does not happen, Emacs sometimes freezes for a couple
of seconds especially when an inferior-octave buffer is visible.


In GNU Emacs 25.1.1 (x86_64-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2017-04-23, modified by Debian built on trouble
Windowing system distributor 'The X.Org Foundation', version 11.0.11902000
System Description:     Debian GNU/Linux 9.0 (stretch)

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/emacs25:/etc/emacs:/usr/local/share/emacs/25.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/25.1/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --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/emacs25:/etc/emacs:/usr/local/share/emacs/25.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/25.1/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --with-x=yes --with-x-toolkit=lucid
 --with-toolkit-scroll-bars --without-gconf --without-gsettings
 'CFLAGS=-g -O2
 -fdebug-prefix-map=/build/emacs25-d2FC1K/emacs25-25.1+1=. 
-fstack-protector-strong
 -Wformat -Werror=format-security -Wall' 'CPPFLAGS=-Wdate-time
 -D_FORTIFY_SOURCE=2' LDFLAGS=-Wl,-z,relro'

Configured features:
XAW3D XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS NOTIFY ACL
LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS LUCID X11

Important settings:
  value of $LC_COLLATE: it_IT.UTF-8
  value of $LC_CTYPE: it_IT.UTF-8
  value of $LC_NUMERIC: C
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Octave

Minor modes in effect:
  TeX-PDF-mode: t
  desktop-save-mode: t
  epa-global-mail-mode: t
  shell-dirtrack-mode: t
  openwith-mode: t
  xterm-mouse-mode: t
  display-time-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t
  auto-fill-function: #[128 \300\301\302#\207 [apply smie-auto-fill #[128 
\301\302\300!"\207 [normal-auto-fill-function apply default-value] 4 

(fn &rest ARGS)] nil] 5 nil]
  abbrev-mode: t

Recent messages:
Showing message 774...done
Showing message 774...done
Showing message 775...done
No following nondeleted message
Expunging deleted messages...done
Showing message 773...
Blocking call to accept-process-output with quit inhibited!!
Mark set
kill-region: Buffer is read-only: #<buffer *Messages*>
Making completion list...

Load-path shadows:
~/elisp/bhl hides /usr/share/emacs/25.1/site-lisp/bhl
~/elisp/bhl hides /usr/share/emacs/site-lisp/bhl
/usr/share/emacs/25.1/site-lisp/debian-startup hides 
/usr/share/emacs/site-lisp/debian-startup
/usr/share/emacs25/site-lisp/flim/md4 hides /usr/share/emacs/25.1/lisp/md4
/usr/share/emacs25/site-lisp/flim/hex-util hides 
/usr/share/emacs/25.1/lisp/hex-util
/usr/share/emacs/site-lisp/rst hides /usr/share/emacs/25.1/lisp/textmodes/rst
~/elisp/bibtex hides /usr/share/emacs/25.1/lisp/textmodes/bibtex
/usr/share/emacs25/site-lisp/flim/ntlm hides /usr/share/emacs/25.1/lisp/net/ntlm
/usr/share/emacs25/site-lisp/flim/hmac-md5 hides 
/usr/share/emacs/25.1/lisp/net/hmac-md5
/usr/share/emacs25/site-lisp/flim/sasl-ntlm hides 
/usr/share/emacs/25.1/lisp/net/sasl-ntlm
/usr/share/emacs25/site-lisp/flim/sasl-digest hides 
/usr/share/emacs/25.1/lisp/net/sasl-digest
/usr/share/emacs25/site-lisp/flim/sasl hides /usr/share/emacs/25.1/lisp/net/sasl
/usr/share/emacs25/site-lisp/flim/sasl-cram hides 
/usr/share/emacs/25.1/lisp/net/sasl-cram
/usr/share/emacs25/site-lisp/flim/hmac-def hides 
/usr/share/emacs/25.1/lisp/net/hmac-def
/usr/share/emacs25/site-lisp/auctex/tex-fold hides 
/usr/share/emacs/site-lisp/auctex/tex-fold
/usr/share/emacs25/site-lisp/auctex/context-en hides 
/usr/share/emacs/site-lisp/auctex/context-en
/usr/share/emacs25/site-lisp/auctex/tex-info hides 
/usr/share/emacs/site-lisp/auctex/tex-info
/usr/share/emacs25/site-lisp/auctex/plain-tex hides 
/usr/share/emacs/site-lisp/auctex/plain-tex
/usr/share/emacs25/site-lisp/auctex/tex-mik hides 
/usr/share/emacs/site-lisp/auctex/tex-mik
/usr/share/emacs25/site-lisp/auctex/texmathp hides 
/usr/share/emacs/site-lisp/auctex/texmathp
/usr/share/emacs25/site-lisp/auctex/context-nl hides 
/usr/share/emacs/site-lisp/auctex/context-nl
/usr/share/emacs25/site-lisp/auctex/toolbar-x hides 
/usr/share/emacs/site-lisp/auctex/toolbar-x
/usr/share/emacs25/site-lisp/auctex/tex hides 
/usr/share/emacs/site-lisp/auctex/tex
/usr/share/emacs25/site-lisp/auctex/tex-jp hides 
/usr/share/emacs/site-lisp/auctex/tex-jp
/usr/share/emacs25/site-lisp/auctex/tex-ispell hides 
/usr/share/emacs/site-lisp/auctex/tex-ispell
/usr/share/emacs25/site-lisp/auctex/bib-cite hides 
/usr/share/emacs/site-lisp/auctex/bib-cite
/usr/share/emacs25/site-lisp/auctex/multi-prompt hides 
/usr/share/emacs/site-lisp/auctex/multi-prompt
/usr/share/emacs25/site-lisp/auctex/font-latex hides 
/usr/share/emacs/site-lisp/auctex/font-latex
/usr/share/emacs25/site-lisp/auctex/prv-emacs hides 
/usr/share/emacs/site-lisp/auctex/prv-emacs
/usr/share/emacs25/site-lisp/auctex/tex-style hides 
/usr/share/emacs/site-lisp/auctex/tex-style
/usr/share/emacs25/site-lisp/auctex/context hides 
/usr/share/emacs/site-lisp/auctex/context
/usr/share/emacs25/site-lisp/auctex/preview hides 
/usr/share/emacs/site-lisp/auctex/preview
/usr/share/emacs25/site-lisp/auctex/tex-font hides 
/usr/share/emacs/site-lisp/auctex/tex-font
/usr/share/emacs25/site-lisp/auctex/tex-bar hides 
/usr/share/emacs/site-lisp/auctex/tex-bar
/usr/share/emacs25/site-lisp/auctex/latex hides 
/usr/share/emacs/site-lisp/auctex/latex
/usr/share/emacs25/site-lisp/auctex/tex-buf hides 
/usr/share/emacs/site-lisp/auctex/tex-buf

Features:
(shadow emacsbug nero url-handlers timezone rmailsort rmailkwd macros
rmailedit dabbrev face-remap url-util rmailout shr-color color
time-stamp mailalias misearch multi-isearch server jka-compr bibtex
sh-script executable generic image-mode vc-filewise vc-rcs js json map
imenu info sgml-mode octave smie cc-mode cc-fonts cc-guess cc-menus
cc-cmds cc-styles cc-align cc-engine cc-vars cc-defs latexenc preview
prv-emacs noutline outline vc-dispatcher vc-svn tex-bar toolbar-x
font-latex plain-tex tex-buf latex easy-mmode edmacro kmacro tex-ispell
tex-style tex dbus xml crm tex-mode compile qp shr dom subr-x browse-url
rmailmm message rfc822 mml mml-sec mm-decode mm-bodies mm-encode
mailabbrev gmm-utils mailheader mail-parse rfc2231 desktop frameset
solar cal-dst pot skeleton warnings rmailsum rmail sendmail rfc2047
rfc2045 ietf-drums mime-compose epa-mail mail-utils epa derived epg view
holidays hol-loaddefs appt diary-lib diary-loaddefs cal-menu calendar
cal-loaddefs tramp tramp-compat tramp-loaddefs trampver ucs-normalize
shell pcomplete comint ring format-spec advice bhl visual-fill-column
switch-to-shell openwith hi-lock xt-mouse ffap thingatpt url-parse
auth-source cl-seq eieio eieio-core cl-macs gnus-util time-date mm-util
help-fns mail-prsvr password-cache url-vars scroll-in-place filladapt
ansi-color time quail dired-x dired generic-x disp-table finder-inf
package epg-config seq byte-opt gv bytecomp byte-compile cl-extra
help-mode easymenu cconv cl-loaddefs pcase cl-lib debian-el
debian-el-loaddefs w3m-load vm-autoload vm-autoloads vm-version vm-vars
vm-init preview-latex tex-site auto-loads mule-util tooltip eldoc
electric uniquify ediff-hook vc-hooks lisp-float-type mwheel x-win
term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list newcomment elisp-mode lisp-mode prog-mode register page
menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock font-lock
syntax facemenu font-core frame cl-generic cham georgian utf-8-lang
misc-lang vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms
cp51932 hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese charscript case-table epa-hook jka-cmpr-hook help
simple abbrev minibuffer cl-preloaded 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
dbusbind inotify dynamic-setting font-render-setting x-toolkit x
multi-tty make-network-process emacs)

Memory information:
((conses 16 501140 83314)
 (symbols 48 38883 0)
 (miscs 40 4472 3099)
 (strings 32 88491 12631)
 (string-bytes 1 2960232)
 (vectors 16 61969)
 (vector-slots 8 1796414 229655)
 (floats 8 855 922)
 (intervals 56 22145 326)
 (buffers 976 118))