bug#21796: 25.0.50; exiting ediff can leave Emacs unresponsive to keyboard input

bug#21796: 25.0.50; exiting ediff can leave Emacs unresponsive to keyboard input

[Sean McAfee]

Recipe:

1. Start graphical Emacs with emacs -Q.
2. Create a buffer named "foo" with C-x b foo RET; insert the text "foo\n" there.
3. Create a second buffer named "bar" with C-x 4 b bar RET; insert the
text "bar\n" there.
4. M-x ediff-buffers foo RET bar RET
5. Either exit Ediff immediately with q, or move around and past the
single difference region with n's and p's, then exit.

With an appreciable frequency, after these steps Emacs is left in a
state in which it ignores any further keyboard input.  Mouse
interactions are unaffected, but not particularly useful with no more
keyboard input registering.  I have to close Emacs and restart, but if
Emacs asks me any questions before closing (eg. if I want to save any
modified files, or exit despite some processes still running), I'm
stuck; I cannot respond, so I have to open a terminal and kill the Emacs
process.

The same thing can happen if I use ediff-files instead of ediff-buffers.

The issue does not seem to arise if Emacs is run in non-graphical mode,
ie. by "emacs -Q -nw".




In GNU Emacs 25.0.50.2 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.8)
 of 2015-10-26
Repository revision: 3f828dc76be74e3587af74b5b3e3458f67f2b7ba
Windowing system distributor 'The X.Org Foundation', version 11.0.11600000
System Description:	Ubuntu 14.04.3 LTS

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GCONF GSETTINGS
NOTIFY LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: Emacs-Lisp

Minor modes in effect:
  global-anzu-mode: t
  anzu-mode: t
  dtrt-indent-mode: t
  projectile-global-mode: t
  projectile-mode: t
  elisp-slime-nav-mode: t
  diff-auto-refine-mode: t
  global-git-commit-mode: t
  async-bytecomp-package-mode: t
  shell-dirtrack-mode: t
  google-this-mode: t
  global-flycheck-mode: t
  flycheck-mode: t
  minibuffer-depth-indicate-mode: t
  ido-everywhere: t
  global-undo-tree-mode: t
  undo-tree-mode: t
  paredit-mode: t
  override-global-mode: t
  show-paren-mode: t
  electric-pair-mode: t
  savehist-mode: t
  desktop-save-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-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
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
Note: standard-indent adjusted to 2
Note: sgml-basic-offset adjusted to 4
Note: sgml-basic-offset adjusted to 8
Note: indent-tabs-mode adjusted to t
Note: sgml-basic-offset adjusted to 4
Note: standard-indent adjusted to 5
Note: standard-indent adjusted to 2
Wrote /home/smcafee1/.emacs.d/.emacs.desktop.lock
Desktop: 94 buffers restored.
For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:
~/emacs/japanese hides /usr/local/share/emacs/25.0.50/lisp/language/japanese

Features:
(shadow sort mail-extr emacsbug markdown-mode php-mode speedbar sb-image
ezimage dframe sh-script executable conf-mode org-element org-rmail
org-mhe org-irc org-info org-gnus org-docview doc-view jka-compr
image-mode org-bibtex bibtex org-bbdb org-w3m the-org-mode-expansions
org org-macro org-footnote org-pcomplete org-list org-faces org-entities
noutline outline org-version ob-emacs-lisp ob ob-tangle ob-ref ob-lob
ob-table ob-exp org-src ob-keys ob-comint ob-core ob-eval org-compat
org-macs org-loaddefs cal-menu calendar cal-loaddefs cap-words superword
subword ensime-company yasnippet company scala-mode2 scala-mode2-imenu
scala-mode2-sbt scala-mode2-map scala-mode2-fontlock scala-mode2-indent
scala-mode2-paragraph scala-mode2-lib gnus-dired restclient
css-mode-expansions css-mode smie tagedit html-mode-expansions sgml-mode
js-mode-expansions js imenu cc-mode-expansions cc-mode cc-fonts cc-guess
cc-menus cc-cmds cc-styles cc-align cc-engine cc-vars cc-defs anzu vc
vc-dispatcher vc-git smtpmail-multi smtpmail ensime ensime-sbt sbt-mode
sbt-mode-rgrep sbt-mode-comint sbt-mode-buffer sbt-mode-project
ensime-http ensime-ui ensime-semantic-highlight ensime-doc ensime-search
ensime-undo ensime-startup ensime-refactor ensime-popup ensime-notes
ensime-model ensime-mode ensime-inspector ensime-goto-testfile
ensime-editor popup ensime-debug gdb-mi bindat gud ensime-stacktrace
ensime-inf ensime-completion-util scala-mode2-syntax ensime-config
ensime-util ensime-client ensime-vars s ucs-normalize flymake hideshow
pp arc-mode archive-mode url-gw ensime-macros zenburn-theme
dash-functional json hydra lv dtrt-indent projectile grep ibuf-ext
ibuffer elisp-slime-nav etags xref project magit-blame magit-stash
magit-bisect magit-remote magit-commit magit-sequence magit magit-apply
magit-wip magit-log magit-diff smerge-mode diff-mode magit-core
magit-process magit-popup magit-mode magit-git crm magit-section
magit-utils git-commit log-edit message sendmail rfc822 mml mml-sec
mm-decode mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045
ietf-drums mailabbrev gmm-utils mailheader pcvs-util add-log with-editor
async-bytecomp async tramp-sh tramp tramp-compat tramp-loaddefs trampver
shell pcomplete format-spec google-this url url-proxy url-privacy
url-expand url-methods url-history url-cookie url-domsuf url-util
url-parse auth-source password-cache url-vars mailcap flycheck find-func
rx subr-x dash gnus gnus-ems nnheader gnus-util mail-utils mm-util
help-fns mail-prsvr wid-edit mb-depth ido seq dired-details+ dired
dired-details change-inner expand-region text-mode-expansions
er-basic-expansions expand-region-core advice expand-region-custom
org-bullets undo-tree diff ack compile paredit edmacro kmacro
use-package diminish bind-key easy-mmode finder-inf eieio byte-opt
bytecomp byte-compile cl-extra help-mode cconv eieio-core info package
easymenu epg-config paren elec-pair savehist desktop frameset server
hippie-exp comint ansi-color ring thingatpt cl-seq perl-mode cl-macs cl
gv cl-loaddefs pcase cl-lib time-date 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 system-font-setting font-render-setting
move-toolbar gtk x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 595672 42244)
 (symbols 48 53276 0)
 (miscs 40 2272 1109)
 (strings 32 138273 21222)
 (string-bytes 1 4507571)
 (vectors 16 79906)
 (vector-slots 8 1961599 117490)
 (floats 8 467 515)
 (intervals 56 5532 117)
 (buffers 976 105)
 (heap 1024 86573 2200))

bug#21796: 25.0.50; exiting ediff can leave Emacs unresponsive to keyboard input

[Eli Zaretskii]

> From: Sean McAfee <smcafee@sungevity.com>
> Date: Fri, 30 Oct 2015 17:02:24 -0700
> 
> 1. Start graphical Emacs with emacs -Q.
> 2. Create a buffer named "foo" with C-x b foo RET; insert the text "foo\n" there.
> 3. Create a second buffer named "bar" with C-x 4 b bar RET; insert the
> text "bar\n" there.
> 4. M-x ediff-buffers foo RET bar RET
> 5. Either exit Ediff immediately with q, or move around and past the
> single difference region with n's and p's, then exit.
> 
> With an appreciable frequency, after these steps Emacs is left in a
> state in which it ignores any further keyboard input.  Mouse
> interactions are unaffected, but not particularly useful with no more
> keyboard input registering.  I have to close Emacs and restart, but if
> Emacs asks me any questions before closing (eg. if I want to save any
> modified files, or exit despite some processes still running), I'm
> stuck; I cannot respond, so I have to open a terminal and kill the Emacs
> process.

I cannot reproduce this.  Emacs doesn't become unresponsive when I try
this recipe.

When this happens, can you attach a debugger and show both a C
backtrace and a Lisp backtrace?

bug#21796: 25.0.50; exiting ediff can leave Emacs unresponsive to keyboard input

[Eli Zaretskii]

[Please keep the bug address on the CC list.]

> From: Sean McAfee <smcafee@sungevity.com>
> Date: Mon, 16 Nov 2015 11:42:19 -0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> > I cannot reproduce this.  Emacs doesn't become unresponsive when I try
> > this recipe.
> >
> > When this happens, can you attach a debugger and show both a C
> > backtrace and a Lisp backtrace?
> 
> Here's the C backtrace:
> 
> (gdb) bt
> #0  0x00007f15b2756e79 in __pselect (nfds=nfds@entry=14, 
>     readfds=readfds@entry=0x7ffe77cde630, 
>     writefds=writefds@entry=0x7ffe77cde6b0, exceptfds=exceptfds@entry=0x0, 
>     timeout=<optimized out>, timeout@entry=0x7ffe77cdec40, 
>     sigmask=sigmask@entry=0x0) at ../sysdeps/unix/sysv/linux/pselect.c:77
> #1  0x00000000005cedcd in xg_select (fds_lim=14, 
>     rfds=rfds@entry=0x7ffe77cdee00, wfds=wfds@entry=0x7ffe77cdee80, 
>     efds=efds@entry=0x0, timeout=timeout@entry=0x7ffe77cdec40, 
>     sigmask=sigmask@entry=0x0) at xgselect.c:113
> #2  0x0000000000599361 in wait_reading_process_output (
>     time_limit=time_limit@entry=0, nsecs=nsecs@entry=0, 
>     read_kbd=read_kbd@entry=-1, do_display=true, 
>     wait_for_cell=wait_for_cell@entry=0, wait_proc=wait_proc@entry=0x0, 
>     just_wait_proc=just_wait_proc@entry=0) at process.c:4842
> #3  0x00000000004f4885 in kbd_buffer_get_event (end_time=0x0, 
>     used_mouse_menu=0x7ffe77cdf6eb, kbp=<synthetic pointer>) at keyboard.c:3805

This says that Emacs waits for you to type something.  I don't see any
signs of lack of responsiveness here.

Are you sure you see no question in the minibuffer at this point?

bug#21796: 25.0.50; exiting ediff can leave Emacs unresponsive to keyboard input

[Sean McAfee]

Eli Zaretskii <eliz@gnu.org> writes:
>> Here's the C backtrace:
>> 
>> (gdb) bt
>> #0  0x00007f15b2756e79 in __pselect (nfds=nfds@entry=14, 
>>     readfds=readfds@entry=0x7ffe77cde630, 
>>     writefds=writefds@entry=0x7ffe77cde6b0, exceptfds=exceptfds@entry=0x0, 
>>     timeout=<optimized out>, timeout@entry=0x7ffe77cdec40, 
>>     sigmask=sigmask@entry=0x0) at ../sysdeps/unix/sysv/linux/pselect.c:77
>> #1  0x00000000005cedcd in xg_select (fds_lim=14, 
>>     rfds=rfds@entry=0x7ffe77cdee00, wfds=wfds@entry=0x7ffe77cdee80, 
>>     efds=efds@entry=0x0, timeout=timeout@entry=0x7ffe77cdec40, 
>>     sigmask=sigmask@entry=0x0) at xgselect.c:113
>> #2  0x0000000000599361 in wait_reading_process_output (
>>     time_limit=time_limit@entry=0, nsecs=nsecs@entry=0, 
>>     read_kbd=read_kbd@entry=-1, do_display=true, 
>>     wait_for_cell=wait_for_cell@entry=0, wait_proc=wait_proc@entry=0x0, 
>>     just_wait_proc=just_wait_proc@entry=0) at process.c:4842
>> #3  0x00000000004f4885 in kbd_buffer_get_event (end_time=0x0, 
>>     used_mouse_menu=0x7ffe77cdf6eb, kbp=<synthetic pointer>) at keyboard.c:3805

> This says that Emacs waits for you to type something.  I don't see any
> signs of lack of responsiveness here.
>
> Are you sure you see no question in the minibuffer at this point?

Yes.  I just did it again to be extra sure.

Then I clicked in the echo area, which caused the *Messages* buffer to
appear, and the last line says "Quit this Ediff session? (y or n) y".

As before, mouse input is complete normal; I can activate menu items,
drag the mode line for the upper window around to resize it, etc, but no
keyboard input registers.  In particular typing C-g a bunch of times has
no effect, nor does C-x C-c after that.

For completeness, in case this wasn't captured in my original bug
report, I'll mention that during these experiments I'm running Emacs on
Ubuntu inside of a VirtualBox instance on a Mac.  There's one other
Emacs-related peculiarity I notice only in this environment: whenever I
start Emacs and desktop-save-mode is restoring my buffers (which takes
much longer than elsewhere for a comparable number of buffers), the
entire system slows to a crawl.

bug#21796: emacs not responding to keyboard events

[Mohammad Toossi]

[-- Attachment #1: Type: text/plain, Size: 1681 bytes --]

I am most likely affected by the same issue: when emacs is launched to
compose a git commit message, it sometimes ignores all keyboard input, but
mouse input works normally.  I am using Emacs 24.5.1, Ubuntu 14.04, and I3
WM.

Even more surprisingly, emacs responds to X KeyPress events sent to it
through "xdotool", but not through the real keyboard.  Also, "xev"
indicates that emacs is receiving all KeyPress events and just dropping
them internally.

After spending some time attaching GDB and stepping through code, I have
found that x_filter_event() is the point in which the KeyPress event gets
dropped.  In a good emacs instance, event_handler_gtk receives the event
and passes it on to handle_one_xevent.  In a bad instance,
event_handler_gdk still receives the event but never passes any KeyPress
event to handle_one_xevent.  In bad instances, x_filter_event always
returns true for real key presses, but returns false for fake key presses
from xdotool.

My best guess at this point is that the issue is something along the lines
of [1].  Slowing down the system increases the likelihood of this race
condition(?) happening.

To take it even further, I used xscope to intercept the emacs messages
to/from X, and put a breakpoint on SYNC-Request messages.  Stepping through
the subsequent X messages one by one triggered the bug (1 out of 1 times)
further suggesting that this is a timing issue.

I'm skipping a lot of detail here in order to keep this short.  Feel free
to ask me for more specifics.

[1] XIM SYNC_REPLY not sent when switching input contexts <
https://bugs.freedesktop.org/show_bug.cgi?id=7869>
[2] http://ftp.x.org/pub/individual/app/xscope-1.4.1.tar.gz

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bug#21796: 24.5; exiting ediff can leave Emacs unresponsive to keyboard input

[johannes.muelmenstaedt]

I am affected by bug#21796 as well, in emacs-24.5.1.  I can still interact with
the emacs process through emacsclient -nw.  If this is useful for debugging,
please let me know what you want me to do.


In GNU Emacs 24.5.1 (x86_64-pc-linux-gnu, GTK+ Version 3.10.8)
 of 2016-02-24 on queensboro-bridge, modified by Debian
Windowing system distributor `The X.Org Foundation', version 11.0.11501000
System Description:	Ubuntu 14.04.4 LTS

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 --param=ssp-buffer-size=4 -Wformat -Werror=format-security
 -Wall' CPPFLAGS=-D_FORTIFY_SOURCE=2 'LDFLAGS=-Wl,-Bsymbolic-functions
 -Wl,-z,relro''

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: ESS[S]

Minor modes in effect:
  electric-pair-mode: t
  show-paren-mode: t
  display-time-mode: t
  shell-dirtrack-mode: t
  ess-roxy-mode: t
  eldoc-mode: t
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-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:
Buffer A: Processing difference region 0 of 19
Buffer A: Processing difference region 10 of 19
Buffer B: Processing difference region 0 of 19
Buffer B: Processing difference region 10 of 19
Processing difference regions ... done
Making completion list... [2 times]
Quit this Ediff session? (y or n) y
M-[ 2 7 ; 3 is undefined
Undo!
Making completion list...

Load-path shadows:
/usr/share/emacs/24.5/site-lisp/debian-startup hides /usr/share/emacs/site-lisp/debian-startup
/usr/share/emacs/24.5/site-lisp/tex-site hides /usr/share/emacs/site-lisp/tex-site
/usr/share/emacs/24.5/site-lisp/auctex hides /usr/share/emacs/site-lisp/auctex
/usr/share/emacs/24.5/site-lisp/preview-latex hides /usr/share/emacs/site-lisp/preview-latex
~/gnus/lisp/password-cache hides /usr/share/emacs/24.5/lisp/password-cache
~/gnus/lisp/color hides /usr/share/emacs/24.5/lisp/color
~/gnus/lisp/format-spec hides /usr/share/emacs/24.5/lisp/format-spec
~/gnus/lisp/md4 hides /usr/share/emacs/24.5/lisp/md4
~/gnus/lisp/hex-util hides /usr/share/emacs/24.5/lisp/hex-util
~/gnus/lisp/dns-mode hides /usr/share/emacs/24.5/lisp/textmodes/dns-mode
~/gnus/lisp/sasl-ntlm hides /usr/share/emacs/24.5/lisp/net/sasl-ntlm
~/gnus/lisp/dns hides /usr/share/emacs/24.5/lisp/net/dns
~/gnus/lisp/sasl-cram hides /usr/share/emacs/24.5/lisp/net/sasl-cram
~/gnus/lisp/shr-color hides /usr/share/emacs/24.5/lisp/net/shr-color
~/gnus/lisp/dig hides /usr/share/emacs/24.5/lisp/net/dig
~/gnus/lisp/hmac-def hides /usr/share/emacs/24.5/lisp/net/hmac-def
~/gnus/lisp/netrc hides /usr/share/emacs/24.5/lisp/net/netrc
~/gnus/lisp/tls hides /usr/share/emacs/24.5/lisp/net/tls
~/gnus/lisp/sasl-digest hides /usr/share/emacs/24.5/lisp/net/sasl-digest
~/gnus/lisp/ntlm hides /usr/share/emacs/24.5/lisp/net/ntlm
~/gnus/lisp/hmac-md5 hides /usr/share/emacs/24.5/lisp/net/hmac-md5
~/gnus/lisp/sasl hides /usr/share/emacs/24.5/lisp/net/sasl
~/gnus/lisp/shr hides /usr/share/emacs/24.5/lisp/net/shr
~/gnus/lisp/uudecode hides /usr/share/emacs/24.5/lisp/mail/uudecode
~/gnus/lisp/binhex hides /usr/share/emacs/24.5/lisp/mail/binhex
~/gnus/lisp/hashcash hides /usr/share/emacs/24.5/lisp/mail/hashcash
~/gnus/lisp/mail-parse hides /usr/share/emacs/24.5/lisp/gnus/mail-parse
~/gnus/lisp/gnus-demon hides /usr/share/emacs/24.5/lisp/gnus/gnus-demon
~/gnus/lisp/gnus-cite hides /usr/share/emacs/24.5/lisp/gnus/gnus-cite
~/gnus/lisp/gnus-html hides /usr/share/emacs/24.5/lisp/gnus/gnus-html
~/gnus/lisp/nndraft hides /usr/share/emacs/24.5/lisp/gnus/nndraft
~/gnus/lisp/message hides /usr/share/emacs/24.5/lisp/gnus/message
~/gnus/lisp/gnus-bookmark hides /usr/share/emacs/24.5/lisp/gnus/gnus-bookmark
~/gnus/lisp/gnus-int hides /usr/share/emacs/24.5/lisp/gnus/gnus-int
~/gnus/lisp/gnus-gravatar hides /usr/share/emacs/24.5/lisp/gnus/gnus-gravatar
~/gnus/lisp/flow-fill hides /usr/share/emacs/24.5/lisp/gnus/flow-fill
~/gnus/lisp/gnus-cus hides /usr/share/emacs/24.5/lisp/gnus/gnus-cus
~/gnus/lisp/gnus-eform hides /usr/share/emacs/24.5/lisp/gnus/gnus-eform
~/gnus/lisp/gnus-async hides /usr/share/emacs/24.5/lisp/gnus/gnus-async
~/gnus/lisp/ietf-drums hides /usr/share/emacs/24.5/lisp/gnus/ietf-drums
~/gnus/lisp/nntp hides /usr/share/emacs/24.5/lisp/gnus/nntp
~/gnus/lisp/nnspool hides /usr/share/emacs/24.5/lisp/gnus/nnspool
~/gnus/lisp/utf7 hides /usr/share/emacs/24.5/lisp/gnus/utf7
~/gnus/lisp/html2text hides /usr/share/emacs/24.5/lisp/gnus/html2text
~/gnus/lisp/gnus-spec hides /usr/share/emacs/24.5/lisp/gnus/gnus-spec
~/gnus/lisp/sieve-manage hides /usr/share/emacs/24.5/lisp/gnus/sieve-manage
~/gnus/lisp/canlock hides /usr/share/emacs/24.5/lisp/gnus/canlock
~/gnus/lisp/nnmail hides /usr/share/emacs/24.5/lisp/gnus/nnmail
~/gnus/lisp/rfc2047 hides /usr/share/emacs/24.5/lisp/gnus/rfc2047
~/gnus/lisp/nnrss hides /usr/share/emacs/24.5/lisp/gnus/nnrss
~/gnus/lisp/nndir hides /usr/share/emacs/24.5/lisp/gnus/nndir
~/gnus/lisp/gnus-msg hides /usr/share/emacs/24.5/lisp/gnus/gnus-msg
~/gnus/lisp/nnml hides /usr/share/emacs/24.5/lisp/gnus/nnml
~/gnus/lisp/mml1991 hides /usr/share/emacs/24.5/lisp/gnus/mml1991
~/gnus/lisp/gnus-dup hides /usr/share/emacs/24.5/lisp/gnus/gnus-dup
~/gnus/lisp/rtree hides /usr/share/emacs/24.5/lisp/gnus/rtree
~/gnus/lisp/gnus-kill hides /usr/share/emacs/24.5/lisp/gnus/gnus-kill
~/gnus/lisp/smime hides /usr/share/emacs/24.5/lisp/gnus/smime
~/gnus/lisp/nnmbox hides /usr/share/emacs/24.5/lisp/gnus/nnmbox
~/gnus/lisp/pop3 hides /usr/share/emacs/24.5/lisp/gnus/pop3
~/gnus/lisp/nnheader hides /usr/share/emacs/24.5/lisp/gnus/nnheader
~/gnus/lisp/mm-partial hides /usr/share/emacs/24.5/lisp/gnus/mm-partial
~/gnus/lisp/mm-extern hides /usr/share/emacs/24.5/lisp/gnus/mm-extern
~/gnus/lisp/compface hides /usr/share/emacs/24.5/lisp/gnus/compface
~/gnus/lisp/spam-wash hides /usr/share/emacs/24.5/lisp/gnus/spam-wash
~/gnus/lisp/gnus-mlspl hides /usr/share/emacs/24.5/lisp/gnus/gnus-mlspl
~/gnus/lisp/gnus-notifications hides /usr/share/emacs/24.5/lisp/gnus/gnus-notifications
~/gnus/lisp/gnus-logic hides /usr/share/emacs/24.5/lisp/gnus/gnus-logic
~/gnus/lisp/nnregistry hides /usr/share/emacs/24.5/lisp/gnus/nnregistry
~/gnus/lisp/nnoo hides /usr/share/emacs/24.5/lisp/gnus/nnoo
~/gnus/lisp/rfc2104 hides /usr/share/emacs/24.5/lisp/gnus/rfc2104
~/gnus/lisp/nnimap hides /usr/share/emacs/24.5/lisp/gnus/nnimap
~/gnus/lisp/gnus-bcklg hides /usr/share/emacs/24.5/lisp/gnus/gnus-bcklg
~/gnus/lisp/rfc2231 hides /usr/share/emacs/24.5/lisp/gnus/rfc2231
~/gnus/lisp/nnir hides /usr/share/emacs/24.5/lisp/gnus/nnir
~/gnus/lisp/gnus-ems hides /usr/share/emacs/24.5/lisp/gnus/gnus-ems
~/gnus/lisp/mm-view hides /usr/share/emacs/24.5/lisp/gnus/mm-view
~/gnus/lisp/gnus-dired hides /usr/share/emacs/24.5/lisp/gnus/gnus-dired
~/gnus/lisp/ecomplete hides /usr/share/emacs/24.5/lisp/gnus/ecomplete
~/gnus/lisp/gnus-mh hides /usr/share/emacs/24.5/lisp/gnus/gnus-mh
~/gnus/lisp/gnus-delay hides /usr/share/emacs/24.5/lisp/gnus/gnus-delay
~/gnus/lisp/score-mode hides /usr/share/emacs/24.5/lisp/gnus/score-mode
~/gnus/lisp/nndiary hides /usr/share/emacs/24.5/lisp/gnus/nndiary
~/gnus/lisp/nndoc hides /usr/share/emacs/24.5/lisp/gnus/nndoc
~/gnus/lisp/gnus-salt hides /usr/share/emacs/24.5/lisp/gnus/gnus-salt
~/gnus/lisp/sieve-mode hides /usr/share/emacs/24.5/lisp/gnus/sieve-mode
~/gnus/lisp/mm-archive hides /usr/share/emacs/24.5/lisp/gnus/mm-archive
~/gnus/lisp/gnus-registry hides /usr/share/emacs/24.5/lisp/gnus/gnus-registry
~/gnus/lisp/gnus-util hides /usr/share/emacs/24.5/lisp/gnus/gnus-util
~/gnus/lisp/mml2015 hides /usr/share/emacs/24.5/lisp/gnus/mml2015
~/gnus/lisp/plstore hides /usr/share/emacs/24.5/lisp/gnus/plstore
~/gnus/lisp/mm-bodies hides /usr/share/emacs/24.5/lisp/gnus/mm-bodies
~/gnus/lisp/gnus-cache hides /usr/share/emacs/24.5/lisp/gnus/gnus-cache
~/gnus/lisp/smiley hides /usr/share/emacs/24.5/lisp/gnus/smiley
~/gnus/lisp/mail-prsvr hides /usr/share/emacs/24.5/lisp/gnus/mail-prsvr
~/gnus/lisp/mail-source hides /usr/share/emacs/24.5/lisp/gnus/mail-source
~/gnus/lisp/qp hides /usr/share/emacs/24.5/lisp/gnus/qp
~/gnus/lisp/starttls hides /usr/share/emacs/24.5/lisp/gnus/starttls
~/gnus/lisp/mm-util hides /usr/share/emacs/24.5/lisp/gnus/mm-util
~/gnus/lisp/auth-source hides /usr/share/emacs/24.5/lisp/gnus/auth-source
~/gnus/lisp/gnus-win hides /usr/share/emacs/24.5/lisp/gnus/gnus-win
~/gnus/lisp/gnus-ml hides /usr/share/emacs/24.5/lisp/gnus/gnus-ml
~/gnus/lisp/mailcap hides /usr/share/emacs/24.5/lisp/gnus/mailcap
~/gnus/lisp/gnus-srvr hides /usr/share/emacs/24.5/lisp/gnus/gnus-srvr
~/gnus/lisp/mml hides /usr/share/emacs/24.5/lisp/gnus/mml
~/gnus/lisp/gnus-diary hides /usr/share/emacs/24.5/lisp/gnus/gnus-diary
~/gnus/lisp/gnus-fun hides /usr/share/emacs/24.5/lisp/gnus/gnus-fun
~/gnus/lisp/gnus-sum hides /usr/share/emacs/24.5/lisp/gnus/gnus-sum
~/gnus/lisp/registry hides /usr/share/emacs/24.5/lisp/gnus/registry
~/gnus/lisp/gnus-vm hides /usr/share/emacs/24.5/lisp/gnus/gnus-vm
~/gnus/lisp/gnus-group hides /usr/share/emacs/24.5/lisp/gnus/gnus-group
~/gnus/lisp/gnus-uu hides /usr/share/emacs/24.5/lisp/gnus/gnus-uu
~/gnus/lisp/gnus-undo hides /usr/share/emacs/24.5/lisp/gnus/gnus-undo
~/gnus/lisp/deuglify hides /usr/share/emacs/24.5/lisp/gnus/deuglify
~/gnus/lisp/legacy-gnus-agent hides /usr/share/emacs/24.5/lisp/gnus/legacy-gnus-agent
~/gnus/lisp/gnus-setup hides /usr/share/emacs/24.5/lisp/gnus/gnus-setup
~/gnus/lisp/gravatar hides /usr/share/emacs/24.5/lisp/gnus/gravatar
~/gnus/lisp/gnus-sieve hides /usr/share/emacs/24.5/lisp/gnus/gnus-sieve
~/gnus/lisp/nngateway hides /usr/share/emacs/24.5/lisp/gnus/nngateway
~/gnus/lisp/mm-uu hides /usr/share/emacs/24.5/lisp/gnus/mm-uu
~/gnus/lisp/gmm-utils hides /usr/share/emacs/24.5/lisp/gnus/gmm-utils
~/gnus/lisp/nnbabyl hides /usr/share/emacs/24.5/lisp/gnus/nnbabyl
~/gnus/lisp/gssapi hides /usr/share/emacs/24.5/lisp/gnus/gssapi
~/gnus/lisp/gnus-art hides /usr/share/emacs/24.5/lisp/gnus/gnus-art
~/gnus/lisp/nnagent hides /usr/share/emacs/24.5/lisp/gnus/nnagent
~/gnus/lisp/spam-report hides /usr/share/emacs/24.5/lisp/gnus/spam-report
~/gnus/lisp/nnvirtual hides /usr/share/emacs/24.5/lisp/gnus/nnvirtual
~/gnus/lisp/gnus-start hides /usr/share/emacs/24.5/lisp/gnus/gnus-start
~/gnus/lisp/gnus-topic hides /usr/share/emacs/24.5/lisp/gnus/gnus-topic
~/gnus/lisp/gnus-picon hides /usr/share/emacs/24.5/lisp/gnus/gnus-picon
~/gnus/lisp/nneething hides /usr/share/emacs/24.5/lisp/gnus/nneething
~/gnus/lisp/rfc1843 hides /usr/share/emacs/24.5/lisp/gnus/rfc1843
~/gnus/lisp/nnweb hides /usr/share/emacs/24.5/lisp/gnus/nnweb
~/gnus/lisp/sieve hides /usr/share/emacs/24.5/lisp/gnus/sieve
~/gnus/lisp/gnus-sync hides /usr/share/emacs/24.5/lisp/gnus/gnus-sync
~/gnus/lisp/nnfolder hides /usr/share/emacs/24.5/lisp/gnus/nnfolder
~/gnus/lisp/gnus-draft hides /usr/share/emacs/24.5/lisp/gnus/gnus-draft
~/gnus/lisp/nnmairix hides /usr/share/emacs/24.5/lisp/gnus/nnmairix
~/gnus/lisp/yenc hides /usr/share/emacs/24.5/lisp/gnus/yenc
~/gnus/lisp/mml-sec hides /usr/share/emacs/24.5/lisp/gnus/mml-sec
~/gnus/lisp/mml-smime hides /usr/share/emacs/24.5/lisp/gnus/mml-smime
~/gnus/lisp/mm-decode hides /usr/share/emacs/24.5/lisp/gnus/mm-decode
~/gnus/lisp/gnus-agent hides /usr/share/emacs/24.5/lisp/gnus/gnus-agent
~/gnus/lisp/messcompat hides /usr/share/emacs/24.5/lisp/gnus/messcompat
~/gnus/lisp/spam-stat hides /usr/share/emacs/24.5/lisp/gnus/spam-stat
~/gnus/lisp/mm-url hides /usr/share/emacs/24.5/lisp/gnus/mm-url
~/gnus/lisp/gnus hides /usr/share/emacs/24.5/lisp/gnus/gnus
~/gnus/lisp/gnus-range hides /usr/share/emacs/24.5/lisp/gnus/gnus-range
~/gnus/lisp/gnus-score hides /usr/share/emacs/24.5/lisp/gnus/gnus-score
~/gnus/lisp/mm-encode hides /usr/share/emacs/24.5/lisp/gnus/mm-encode
~/gnus/lisp/spam hides /usr/share/emacs/24.5/lisp/gnus/spam
~/gnus/lisp/rfc2045 hides /usr/share/emacs/24.5/lisp/gnus/rfc2045
~/gnus/lisp/nnnil hides /usr/share/emacs/24.5/lisp/gnus/nnnil
~/gnus/lisp/nnmaildir hides /usr/share/emacs/24.5/lisp/gnus/nnmaildir
~/gnus/lisp/nnmh hides /usr/share/emacs/24.5/lisp/gnus/nnmh
~/gnus/lisp/parse-time hides /usr/share/emacs/24.5/lisp/calendar/parse-time
~/gnus/lisp/time-date hides /usr/share/emacs/24.5/lisp/calendar/time-date
/usr/share/emacs/24.5/site-lisp/auctex/toolbar-x hides /usr/share/emacs/site-lisp/auctex/toolbar-x
/usr/share/emacs/24.5/site-lisp/auctex/tex-info hides /usr/share/emacs/site-lisp/auctex/tex-info
/usr/share/emacs/24.5/site-lisp/auctex/preview hides /usr/share/emacs/site-lisp/auctex/preview
/usr/share/emacs/24.5/site-lisp/auctex/tex-fold hides /usr/share/emacs/site-lisp/auctex/tex-fold
/usr/share/emacs/24.5/site-lisp/auctex/tex hides /usr/share/emacs/site-lisp/auctex/tex
/usr/share/emacs/24.5/site-lisp/auctex/latex hides /usr/share/emacs/site-lisp/auctex/latex
/usr/share/emacs/24.5/site-lisp/auctex/context-nl hides /usr/share/emacs/site-lisp/auctex/context-nl
/usr/share/emacs/24.5/site-lisp/auctex/plain-tex hides /usr/share/emacs/site-lisp/auctex/plain-tex
/usr/share/emacs/24.5/site-lisp/auctex/tex-bar hides /usr/share/emacs/site-lisp/auctex/tex-bar
/usr/share/emacs/24.5/site-lisp/auctex/tex-font hides /usr/share/emacs/site-lisp/auctex/tex-font
/usr/share/emacs/24.5/site-lisp/auctex/bib-cite hides /usr/share/emacs/site-lisp/auctex/bib-cite
/usr/share/emacs/24.5/site-lisp/auctex/tex-style hides /usr/share/emacs/site-lisp/auctex/tex-style
/usr/share/emacs/24.5/site-lisp/auctex/tex-jp hides /usr/share/emacs/site-lisp/auctex/tex-jp
/usr/share/emacs/24.5/site-lisp/auctex/context-en hides /usr/share/emacs/site-lisp/auctex/context-en
/usr/share/emacs/24.5/site-lisp/auctex/texmathp hides /usr/share/emacs/site-lisp/auctex/texmathp
/usr/share/emacs/24.5/site-lisp/auctex/prv-emacs hides /usr/share/emacs/site-lisp/auctex/prv-emacs
/usr/share/emacs/24.5/site-lisp/auctex/tex-buf hides /usr/share/emacs/site-lisp/auctex/tex-buf
/usr/share/emacs/24.5/site-lisp/auctex/context hides /usr/share/emacs/site-lisp/auctex/context
/usr/share/emacs/24.5/site-lisp/auctex/tex-mik hides /usr/share/emacs/site-lisp/auctex/tex-mik
/usr/share/emacs/24.5/site-lisp/auctex/font-latex hides /usr/share/emacs/site-lisp/auctex/font-latex
/usr/share/emacs/24.5/site-lisp/auctex/multi-prompt hides /usr/share/emacs/site-lisp/auctex/multi-prompt

Features:
(shadow emacsbug xterm ediff-merg ediff-wind ediff-diff ediff-mult ediff-help
ediff-init ediff-util ediff log-edit add-log pcvs pcvs-parse pcvs-info pcvs-defs
pcvs-util ewoc shr-color color shr mailalias smtpmail sendmail etags dired-aux
sort smiley gnus-cite flow-fill mm-archive mail-extr gnus-bcklg gnus-async pp
mule-util rect solar cal-dst misearch multi-isearch qp gnus-ml ange-ftp
tramp-ftp nndir nndraft nnmh utf-7 nnfolder nnagent nnml gnutls network-stream
starttls nnimap tls utf7 netrc gnus-agent gnus-srvr gnus-score score-mode
nnvirtual gnus-msg gnus-art mm-uu mml2015 mm-view mml-smime smime dig nntp
gnus-cache gnus-sum nnoo gnus-group gnus-undo nnmail mail-source gnus-start
gnus-spec gnus-int gnus-range gnus-win gnus gnus-ems gnus-compat url url-proxy
url-privacy url-expand url-methods url-history url-cookie url-domsuf url-util
url-parse url-vars mailcap nnheader help-mode dabbrev dash-autoloads elec-pair
paren server fortran conf-mode org-element org-rmail org-mhe org-irc org-info
org-gnus org-docview org-bibtex org-bbdb org-w3m org org-macro org-footnote
org-pcomplete org-list org-faces org-entities org-version ob-emacs-lisp ob
ob-tangle ob-ref ob-lob ob-table ob-exp org-src ob-keys ob-comint ob-core
ob-eval org-compat org-macs org-loaddefs find-func cal-menu calendar
cal-loaddefs perl-mode bibtex-style bibtex latexenc reftex-dcr reftex
reftex-vars preview prv-emacs tex-buf texmathp noutline outline font-latex latex
easy-mmode edmacro kmacro tex-style tex dbus xml info epa-file epa derived epg
message idna rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231
rfc2047 rfc2045 ietf-drums mail-utils gmm-utils mailheader f90 cus-edit
cus-start cus-load wid-edit doc-view jka-compr image-mode make-mode sh-script
smie imenu vc-git dired sgml-mode flyspell ispell nxml-uchnm rng-xsd xsd-regexp
rng-cmpct tramp-cache tramp-sh rng-nxml rng-valid rng-loc rng-uri rng-parse
nxml-parse rng-match rng-dt rng-util rng-pttrn nxml-ns nxml-mode nxml-outln
nxml-rap nxml-util nxml-glyph nxml-enc xmltok parse-time vc-cvs ses unsafep
vc-dispatcher vc-svn desktop frameset tramp tramp-compat auth-source eieio
byte-opt bytecomp byte-compile cl-extra cconv eieio-core gnus-util mm-util
mail-prsvr password-cache tramp-loaddefs trampver iso-transl time disp-table
gnus-load mh-e mh-compat mailabbrev mh-acros cl-macs mh-buffers mh-loaddefs
package epg-config ido ess-toolbar ess-mouse mouseme thingatpt browse-url
ess-menu ess-swv ess-noweb ess-noweb-font-lock-mode ess-bugs-l essd-els
ess-sas-d ess-sas-l ess-sas-a shell pcomplete ess-sta-d ess-sta-l cc-vars
cc-defs make-regexp ess-sp6-d ess-sp3-d ess-julia ess-r-d ess-r-syntax
ess-r-completion ess-tracebug format-spec ess-roxy advice hideshow ess-help
ess-developer eldoc help-fns ess-s-l ess ess-inf compile comint ansi-color ring
ess-mode ess-noweb-mode ess-utils cl gv cl-loaddefs cl-lib ess-custom executable
easymenu ess-compat ess-site jabber-autoloads preview-latex tex-site auto-loads
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 2322328 263544)
 (symbols 48 76626 0)
 (miscs 40 63385 21197)
 (strings 32 175306 25946)
 (string-bytes 1 4787376)
 (vectors 16 118977)
 (vector-slots 8 2367345 435798)
 (floats 8 3831 3582)
 (intervals 56 406300 4692)
 (buffers 960 358)
 (heap 1024 204454 4447))

bug#21796:

[Mark Grosen]

[-- Attachment #1: Type: text/plain, Size: 7757 bytes --]

Here's my reproduction of this bug. I do not get any output from xbacktrace
(i did source src/.gdbinit)

In GNU Emacs 24.5.3 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.8)
 of 2016-06-16 on ula034034-w1
Windowing system distributor `The X.Org Foundation', version 11.0.11501000
System Description: Ubuntu 14.04.4 LTS

Configured using:
 `configure --prefix=/home/a0324034/emacs'

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-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

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Quit
Making completion list...

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
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 help-mode easymenu 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 72087 5028)
 (symbols 48 17638 0)
 (miscs 40 40 113)
 (strings 32 9276 4364)
 (string-bytes 1 258403)
 (vectors 16 8987)
 (vector-slots 8 383754 17180)
 (floats 8 64 275)
 (intervals 56 173 4)
 (buffers 960 12)
 (heap 1024 25044 893))


(gdb) thread apply all bt

Thread 4 (Thread 0x7fe956851700 (LWP 3454)):
#0  0x00007fe95d754fdd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007fe961302fe4 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fe9613030ec in g_main_context_iteration ()
   from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fe961303129 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007fe961327f05 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007fe95da35184 in start_thread (arg=0x7fe956851700)
    at pthread_create.c:312
#6  0x00007fe95d76237d in clone ()
    at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 3 (Thread 0x7fe955819700 (LWP 3455)):
#0  0x00007fe95d754fdd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007fe961302fe4 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fe9613030ec in g_main_context_iteration ()
   from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fe9558211ad in ?? ()
   from /usr/lib/x86_64-linux-gnu/gio/modules/libdconfsettings.so
#4  0x00007fe961327f05 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007fe95da35184 in start_thread (arg=0x7fe955819700)
    at pthread_create.c:312
#6  0x00007fe95d76237d in clone ()
    at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 2 (Thread 0x7fe94ffff700 (LWP 3456)):
#0  0x00007fe95d754fdd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007fe961302fe4 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fe96130330a in g_main_loop_run ()
   from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fe962063336 in ?? () from
/usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
#4  0x00007fe961327f05 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007fe95da35184 in start_thread (arg=0x7fe94ffff700)
    at pthread_create.c:312
#6  0x00007fe95d76237d in clone ()
    at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7fe963eaca80 (LWP 3453)):
#0  __GI___pthread_mutex_lock (mutex=0x13b8e00)
    at ../nptl/pthread_mutex_lock.c:122
---Type <return> to continue, or q <return> to quit---
#1  0x00007fe961344981 in g_mutex_lock ()
   from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fe961302699 in g_main_context_prepare ()
   from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fe961302f03 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007fe961303097 in g_main_context_pending ()
   from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007fe962746e9d in gtk_events_pending ()
   from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#6  0x00000000004ba4fb in XTread_socket (terminal=<optimized out>,
    hold_quit=0x7fffcff83d70) at xterm.c:7011
#7  0x00000000004ecbe1 in gobble_input () at keyboard.c:6851
#8  0x00000000004ec605 in handle_async_input () at keyboard.c:7091
#9  process_pending_signals () at keyboard.c:7105
#10 0x000000000053dd42 in Fmake_list (length=<optimized out>, init=12144946)
    at alloc.c:2637
#11 0x000000000055c7f8 in concat (nargs=nargs@entry=1,
    args=args@entry=0x7fffcff83ee8, target_type=Lisp_Cons,
    last_special=last_special@entry=false) at fns.c:588
#12 0x000000000055d321 in Fcopy_sequence (arg=19525990) at fns.c:456
#13 0x00000000004eb416 in timer_check () at keyboard.c:4572
#14 0x00000000004eb921 in readable_events (flags=1) at keyboard.c:3448
#15 0x00000000004ecce8 in get_input_pending (flags=1) at keyboard.c:6766
#16 0x00000000004f0134 in detect_input_pending_run_timers (
    do_display=do_display@entry=true) at keyboard.c:9895
#17 0x0000000000595ac6 in wait_reading_process_output (
    time_limit=time_limit@entry=30, nsecs=nsecs@entry=0,
    read_kbd=read_kbd@entry=-1, do_display=do_display@entry=true,
    wait_for_cell=12144946, wait_proc=wait_proc@entry=0x0,
    just_wait_proc=just_wait_proc@entry=0) at process.c:4702
#18 0x0000000000421a74 in sit_for (timeout=<optimized out>,
    reading=reading@entry=true, display_option=display_option@entry=1)
    at dispnew.c:5867
#19 0x00000000004f0e54 in read_char (commandflag=1, map=map@entry=38081766,
    prev_event=12144946, used_mouse_menu=used_mouse_menu@entry
=0x7fffcff8472b,
    end_time=end_time@entry=0x0) at keyboard.c:2810
#20 0x00000000004f232f in read_key_sequence (
    keybuf=keybuf@entry=0x7fffcff84800, prompt=12144946,
    dont_downcase_last=dont_downcase_last@entry=false,
    can_return_switch_frame=can_return_switch_frame@entry=true,
    fix_current_buffer=fix_current_buffer@entry=true,
---Type <return> to continue, or q <return> to quit---
    prevent_redisplay=prevent_redisplay@entry=false, bufsize=30)
    at keyboard.c:9089
#21 0x00000000004f3f20 in command_loop_1 () at keyboard.c:1453
#22 0x0000000000555b4e in internal_condition_case (
    bfun=bfun@entry=0x4f3d30 <command_loop_1>, handlers=<optimized out>,
    hfun=hfun@entry=0x4eaca0 <cmd_error>) at eval.c:1348
#23 0x00000000004e63de in command_loop_2 (ignore=ignore@entry=12144946)
    at keyboard.c:1178
#24 0x0000000000555a5b in internal_catch (tag=12192450,
    func=func@entry=0x4e63c0 <command_loop_2>, arg=12144946) at eval.c:1112
#25 0x00000000004ea8c7 in command_loop () at keyboard.c:1157
#26 recursive_edit_1 () at keyboard.c:778
#27 0x00000000004eabdd in Frecursive_edit () at keyboard.c:849
#28 0x0000000000417c95 in main (argc=<optimized out>, argv=0x7fffcff84b58)
    at emacs.c:1642
(gdb) xbacktrace
(gdb)

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bug#21796:

[Jonathan Doull]

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I first encountered this bug circa 2014 (Emacs 23) - always after using
ediff. Previous to that (date and version) Emacs was rock-solid, so the
problem must have been introduced around then, and it's followed me across
Ubuntu upgrades from 12 to 14.

This bug causes me to restart Emacs a few times every hour during heavy
usage, which is very disruptive, and has stopped Emacs being fun.

The bug is tagged with "moreinfo", however I'm uncertain how to improve on
the quality of reporting that precedes me. I'm happy to assist with
diagnosis if instructed.

In the meantime do any fellow sufferers know a workaround (apart from
dropping ediff)?

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bug#21796:

[Noam Postavsky]

On Fri, Jun 23, 2017 at 11:47 AM, Jonathan Doull
<jonathan@hotlink.technology> wrote:
> This bug causes me to restart Emacs a few times every hour during heavy
> usage, which is very disruptive, and has stopped Emacs being fun.
>
> The bug is tagged with "moreinfo", however I'm uncertain how to improve on
> the quality of reporting that precedes me. I'm happy to assist with
> diagnosis if instructed.
>
> In the meantime do any fellow sufferers know a workaround (apart from
> dropping ediff)?
>

It looks like all reporters were using GTK, does the problem go away
if you ./configure --with-x-toolkit=lucid?

bug#21796:

[Jonathan Doull]

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Thanks - actually that does seem more stable (several ediffs now and no
crash so far).

For other sufferers - Ubuntu provides a lucid specific package
emacs24-lucid.

I'll report back if problem recurs.

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bug#21796:

[martin rudalics]

 > In the meantime do any fellow sufferers know a workaround (apart from
 > dropping ediff)?

Could you try with ‘ediff-window-setup-function’ set to
‘ediff-setup-windows-plain’?

martin

bug#21796:

[Jonathan Doull]

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I'm not sure how to apply your suggestion - ediff-window-setup-function is
obsolete on my Emacs 24.5.

describe-function returns this:

---
ediff-choose-window-setup-function-automatically is a compiled Lisp
function in `ediff-wind.el'.

(ediff-choose-window-setup-function-automatically)

This function is obsolete since 24.3;
use `ediff-setup-windows-default' instead.

Not documented.

[back]

---


The replacement function ediff-setup-windows-default is described as:

---

ediff-setup-windows-default is a compiled Lisp function in

`ediff-wind.el'.

(ediff-setup-windows-default BUFFER-A BUFFER-B BUFFER-C CONTROL-BUFFER)

Not documented.

[back]

---






*Jonathan Doull / *Director

On Fri, Jun 23, 2017 at 6:23 PM, martin rudalics <rudalics@gmx.at> wrote:

> > In the meantime do any fellow sufferers know a workaround (apart from
> > dropping ediff)?
>
> Could you try with ‘ediff-window-setup-function’ set to
> ‘ediff-setup-windows-plain’?
>
> martin
>
>

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bug#21796:

[martin rudalics]

 > I'm not sure how to apply your suggestion - ediff-window-setup-function is
 > obsolete on my Emacs 24.5.

I meant doing something like

(custom-set-variables
  '(ediff-window-setup-function (quote ediff-setup-windows-plain)))

in your .emacs.

The reason is that I'm convinced that the problem you and others see
here is related to focus redirection for minibuffer-less frames.  In

https://debbugs.gnu.org/cgi/bugreport.cgi?bug=24500

I provided a scenario where C-g won't get you back to a reasonable state
either (look for a function called ‘my-other-window’).

martin

bug#21796: exiting ediff can leave Emacs unresponsive to keyboard input

[Noam Postavsky]

On Fri, Jun 23, 2017 at 1:54 PM, Jonathan Doull
<jonathan@hotlink.technology> wrote:
> I'm not sure how to apply your suggestion - ediff-window-setup-function is
> obsolete on my Emacs 24.5.
>
> describe-function returns this:

I expect Martin meant the variable, not the function; i.e., do this:

(setq ediff-window-setup-function #'ediff-setup-windows-plain)

bug#21796: exiting ediff can leave Emacs unresponsive to keyboard input

[martin rudalics]

> I expect Martin meant the variable, not the function; i.e., do this:
>
> (setq ediff-window-setup-function #'ediff-setup-windows-plain)

Indeed.

martin

bug#21796: exiting ediff can leave Emacs unresponsive to keyboard input

[Jonathan Doull]

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I've made this adjustment in my .emacs

> (setq ediff-window-setup-function #'ediff-setup-windows-plain)

and run for a few days now without any hangs, so I'd say this looks like a
good workaround.

Thanks.

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bug#21796: exiting ediff can leave Emacs unresponsive to keyboard input

[martin rudalics]

 > I've made this adjustment in my .emacs
 >
 >> (setq ediff-window-setup-function #'ediff-setup-windows-plain)
 >
 > and run for a few days now without any hangs, so I'd say this looks like a
 > good workaround.

Certainly not!  But it supports my suspicion that focus shifting is
responsible for the problem.  Can you reproduce the original problem at
will so we can play with it?  Would have C-x 5 o got you out of that
stall?  Then it might be sufficient to replace some simple form like

     (if (frame-live-p main-frame)
	(select-frame main-frame))

with

     (if (frame-live-p main-frame)
	(select-frame-set-input-focus main-frame))

martin