bug#35457: 26.2; global-auto-revert-mode cause 100% cpu usage

[Johannes Lundberg]

Add (global-auto-revert-mode 1) to .emacs.
Start Emacs.
Emacs now using 100% cpu.
truss -p <pid> show that Emacs is doing fstatat(), possibly stuck
endless loop.


In GNU Emacs 26.2 (build 1, amd64-portbld-freebsd13.0, GTK+ Version 3.24.7)
Windowing system distributor 'The X.Org Foundation', version 11.0.11804000
Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Configured using:
'configure --disable-build-details --localstatedir=/var --without-gpm
--with-x --enable-acl --without-cairo --with-dbus --with-gconf
--with-gif --with-gnutls --with-gsettings --with-x-toolkit=gtk3
--with-jpeg --with-json --with-file-notification=kqueue --with-lcms2
--with-m17n-flt --with-imagemagick --with-mailutils --with-modules
--with-sound=oss --with-libotf --with-png --with-toolkit-scroll-bars
--with-rsvg --with-threads --with-tiff --with-xft --with-xim
--with-xml2 --with-xpm --without-xwidgets --x-libraries=/usr/local/lib
--x-includes=/usr/local/include --prefix=/usr/local
--mandir=/usr/local/man --disable-silent-rules
--infodir=/usr/local/share/emacs/info/
--build=amd64-portbld-freebsd13.0 'CFLAGS=-O2 -pipe -fstack-protector
-isystem /usr/local/include -fno-strict-aliasing ' 'CPPFLAGS=-isystem
/usr/local/include' 'LDFLAGS= -fstack-protector -L/usr/local/lib ''

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND DBUS GCONF GSETTINGS GLIB
NOTIFY ACL GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS LCMS2

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

Major mode: Fundamental

Minor modes in effect:
tooltip-mode: t
global-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
blink-cursor-mode: t
auto-composition-mode: t
auto-encryption-mode: t
auto-compression-mode: t
buffer-read-only: t
line-number-mode: t
transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs
format-spec rfc822 mml mml-sec epa derived epg gnus-util rmail
rmail-loaddefs mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils elec-pair finder-inf tex-site info package
easymenu epg-config url-handlers url-parse auth-source cl-seq eieio
eieio-core cl-macs eieio-loaddefs password-cache url-vars seq byte-opt
gv bytecomp byte-compile cconv cl-loaddefs cl-lib time-date mule-util
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 menu-bar rfn-eshadow isearch timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors 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 composite charscript charprop case-table epa-hook jka-cmpr-hook
help simple abbrev obarray 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 threads dbusbind kqueue lcms2 dynamic-setting
system-font-setting font-render-setting move-toolbar gtk x-toolkit x
multi-tty make-network-process emacs)

Memory information:
((conses 16 121205 7500)
(symbols 48 22831 1)
(miscs 40 90 116)
(strings 32 37561 1127)
(string-bytes 1 1081297)
(vectors 16 16957)
(vector-slots 8 537814 8932)
(floats 8 52 65)
(intervals 56 299 0)
(buffers 992 12))