The variable global-auto-revert-ignore-modes is not working anymore (it
was working with Emacs 26.3). I've fixed the bug by removing the apostrophe character of the
following line (file: autorevert.el, function: auto-revert--global-add-current-buffer):

  (not (memq 'major-mode global-auto-revert-ignore-modes))


Steps to reproduce:

(progn
  (require 'autorevert)
  (setq global-auto-revert-ignore-modes (list 'Buffer-menu-mode))
  (setq global-auto-revert-non-file-buffers t)
  (global-auto-revert-mode t)
  (list-buffers))





In GNU Emacs 27.0.91 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.30, cairo version 1.16.0)
of 2020-07-04 built on gustavo-Lenovo-ideapad-330-15IKB
Windowing system distributor 'The X.Org Foundation', version 11.0.12008000
System Description: Ubuntu 18.04.4 LTS

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
#<window 7 on *Buffer List*>
Mark set
Making completion list...
Scanning for dabbrevs...done
Type C-x 1 to delete the help window.

Configured using:
'configure --with-x-toolkit=gtk3 --with-modules --with-sound=yes
--with-file-notification=yes --with-mailutils --with-cairo'

Configured features:
XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND GPM DBUS GSETTINGS GLIB NOTIFY
INOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF
ZLIB TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS PDUMPER LCMS2
GMP

Important settings:
value of $LANG: pt_BR.UTF-8
locale-coding-system: utf-8-unix

Major mode: Emacs-Lisp

Minor modes in effect:
global-auto-revert-mode: t
tooltip-mode: t
global-eldoc-mode: t
eldoc-mode: t
electric-indent-mode: t
mouse-wheel-mode: t
tool-bar-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
line-number-mode: t
transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr pp cl-print cl-extra thingatpt help-fns
radix-tree help-mode dabbrev emacsbug message rmc puny dired
dired-loaddefs format-spec rfc822 mml easymenu mml-sec password-cache
epa derived epg epg-config gnus-util rmail rmail-loaddefs
text-property-search time-date subr-x seq byte-opt gv bytecomp
byte-compile cconv mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils autorevert filenotify cl-loaddefs cl-lib
tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel term/x-win x-win term/common-win x-dnd tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode elisp-mode
lisp-mode prog-mode register page tab-bar menu-bar rfn-eshadow isearch
timer select scroll-bar mouse jit-lock font-lock syntax facemenu
font-core term/tty-colors frame minibuffer 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 composite charscript charprop
case-table epa-hook jka-cmpr-hook help simple abbrev obarray
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 threads dbusbind
inotify lcms2 dynamic-setting system-font-setting font-render-setting
cairo move-toolbar gtk x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 54950 31553)
(symbols 48 6444 2)
(strings 32 19050 1937)
(string-bytes 1 575717)
(vectors 16 10323)
(vector-slots 8 135740 9174)
(floats 8 35 22)
(intervals 56 354 130)
(buffers 1000 16))