bug#39343: 27.0.50; Thrad signal crashes Emacs with sgmentation fault

bug#39343: 27.0.50; Thrad signal crashes Emacs with sgmentation fault

[Christian Johansson]

Running following works on Linux but not on macOS.

(let ((loop t)
       (iterations 1))
   (while loop
     (make-thread
      (lambda()
        (message "Thread %d" iterations)
        (signal 'error (list "My error"))))
     (setq iterations (1+ iterations))))

Error in console: Fatal error 11: Segmentation faultAbort trap: 6

It seems to be some kind of issue with quitting threads on macOS which 
is not present on Linux



In GNU Emacs 27.0.50 (build 5, x86_64-apple-darwin18.5.0, NS 
appkit-1671.40 Version 10.14.4 (Build 18E226))
of 2019-07-12 built on Christians-MacBook-Air.local
Repository revision: 8179cbff9ed37e7d8892643859adfad448ae1c7a
Repository branch: master
Windowing system distributor 'Apple', version 10.3.1894
System Description: Mac OS X 10.15.2

Recent messages:
Getting 
/ftp:neojungiantypology.com@ftp.neojungiantypology.com:/.htaccess...done
Wrote /Users/christianjohansson/.emacs.d/.emacs.desktop.lock
Desktop: 1 frame, 27 buffers restored.
Initializing Hyperbole...done
Hyperbole 7.0.6 is ready for action.
For information about GNU Emacs and the GNU system, type C-h C-a.
Ispell process killed
Starting new Ispell process /usr/local/bin/hunspell with svenska 
dictionary...
Source file 
‘/Users/christianjohansson/Documents/emacs/lisp/mail/emacsbug.el’ newer 
than byte-compiled file
Source file 
‘/Users/christianjohansson/Documents/emacs/lisp/mail/sendmail.el’ newer 
than byte-compiled file

Configured features:
RSVG DBUS GLIB NOTIFY KQUEUE ACL GNUTLS LIBXML2 ZLIB TOOLKIT_SCROLL_BARS
NS THREADS PDUMPER GMP

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

Major mode: Org

Minor modes in effect:
global-hl-todo-mode: t
flycheck-color-mode-line-mode: t
show-paren-mode: t
save-place-mode: t
global-diff-hl-mode: t
diff-hl-mode: t
ssh-deploy-line-mode: t
global-auto-complete-mode: t
flyspell-mode: t
editorconfig-mode: t
which-key-mode: t
csv-field-index-mode: t
global-flycheck-mode: t
flycheck-mode: t
async-bytecomp-package-mode: t
yas-global-mode: t
yas-minor-mode: t
override-global-mode: t
ido-everywhere: t
display-time-mode: t
winner-mode: t
electric-pair-mode: t
desktop-save-mode: t
recentf-mode: t
global-semantic-mru-bookmark-mode: t
global-semanticdb-minor-mode: t
global-semantic-idle-completions-mode: t
global-semantic-idle-scheduler-mode: t
global-semantic-idle-local-symbol-highlight-mode: t
global-semantic-idle-summary-mode: t
global-semantic-decoration-mode: t
global-semantic-highlight-func-mode: t
global-semantic-stickyfunc-mode: t
global-semantic-show-parser-state-mode: t
global-semantic-highlight-edits-mode: t
semantic-mode: t
delete-selection-mode: t
display-battery-mode: t
global-whitespace-mode: t
which-function-mode: t
shell-dirtrack-mode: t
tooltip-mode: t
global-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
window-divider-mode: t
auto-composition-mode: t
auto-encryption-mode: t
auto-compression-mode: t
column-number-mode: t
transient-mark-mode: t

Load-path shadows:
/Users/christianjohansson/.emacs.d/phps-mode/phps-mode-analyzer hides 
/Users/christianjohansson/.emacs.d/elpa/phps-mode-20190930.1742/phps-mode-analyzer
/Users/christianjohansson/.emacs.d/phps-mode/phps-mode-tags hides 
/Users/christianjohansson/.emacs.d/elpa/phps-mode-20190930.1742/phps-mode-tags
/Users/christianjohansson/.emacs.d/phps-mode/phps-mode-macros hides 
/Users/christianjohansson/.emacs.d/elpa/phps-mode-20190930.1742/phps-mode-macros
/Users/christianjohansson/.emacs.d/phps-mode/phps-mode-semantic hides 
/Users/christianjohansson/.emacs.d/elpa/phps-mode-20190930.1742/phps-mode-semantic
/Users/christianjohansson/.emacs.d/phps-mode/phps-mode-syntax-table 
hides 
/Users/christianjohansson/.emacs.d/elpa/phps-mode-20190930.1742/phps-mode-syntax-table
/Users/christianjohansson/.emacs.d/phps-mode/phps-mode-flymake hides 
/Users/christianjohansson/.emacs.d/elpa/phps-mode-20190930.1742/phps-mode-flymake
/Users/christianjohansson/.emacs.d/phps-mode/phps-mode hides 
/Users/christianjohansson/.emacs.d/elpa/phps-mode-20190930.1742/phps-mode
/Users/christianjohansson/.emacs.d/ssh-deploy/ssh-deploy hides 
/Users/christianjohansson/.emacs.d/elpa/ssh-deploy-20190917.530/ssh-deploy
/Users/christianjohansson/.emacs.d/ssh-deploy/ssh-deploy-diff-mode hides 
/Users/christianjohansson/.emacs.d/elpa/ssh-deploy-20190917.530/ssh-deploy-diff-mode
/Users/christianjohansson/.emacs.d/ssh-deploy/ssh-deploy-hydra hides 
/Users/christianjohansson/.emacs.d/elpa/ssh-deploy-20190917.530/ssh-deploy-hydra
/Users/christianjohansson/.emacs.d/elpa/less-css-mode-20161001.453/less-css-mode 
hides /Users/christianjohansson/Documents/emacs/lisp/textmodes/less-css-mode
/Users/christianjohansson/.emacs.d/elpa/let-alist-1.0.6/let-alist hides 
/Users/christianjohansson/Documents/emacs/lisp/emacs-lisp/let-alist
/Users/christianjohansson/Documents/emacs/lisp/sb-image hides 
/Users/christianjohansson/Documents/emacs/lisp/obsolete/sb-image
/Users/christianjohansson/Documents/emacs/lisp/url/url-ns hides 
/Users/christianjohansson/Documents/emacs/lisp/obsolete/url-ns
/Users/christianjohansson/Documents/emacs/lisp/emacs-lisp/cl hides 
/Users/christianjohansson/Documents/emacs/lisp/obsolete/cl

Features:
(shadow mail-extr emacsbug sendmail ediff-merg ediff-mult ediff-wind
ediff-diff ediff-help ediff-init ediff-util tramp-cache epa-file
ange-ftp tramp-ftp apache-mode eww mm-url url-queue shr svg org-rmail
org-mhe org-irc org-info org-gnus nnir gnus-sum gnus-group gnus-undo
gnus-start gnus-cloud nnimap nnmail mail-source utf7 netrc nnoo
gnus-spec gnus-int gnus-range message rfc822 mml mml-sec epa epg
mailabbrev gmm-utils mailheader gnus-win gnus nnheader gnus-util rmail
rmail-loaddefs text-property-search org-docview org-bibtex bibtex
org-bbdb org-w3m semantic/imenu semantic/sb semantic/tag-file
semantic/db-file data-debug cedet-files semantic/bovine/c
semantic/decorate/include hideif semantic/bovine/c-by semantic/lex-spp
semantic/bovine/gcc semantic/dep semantic/bovine semantic/analyze/refs
bug-reference display-line-numbers rainbow-mode hl-todo flycheck-rust
flycheck-color-mode-line face-remap editorconfig-core
editorconfig-core-handle editorconfig-fnmatch vc-git init rng-nxml
rng-valid rng-loc rng-uri rng-parse nxml-parse rng-match rng-pttrn
nxml-ns nxml-mode nxml-outln nxml-rap smartparens-html sgml-mode dom
nxml-util nxml-enc xmltok misc ts-comint tss log4e helm helm-source
helm-multi-match helm-lib json-mode json-reformat json-snatcher tide
tide-lv typescript-mode zenburn-theme smarty-mode paren saveplace
restclient smex flycheck-pos-tip pos-tip diff-hl vc-dir ewoc vc
vc-dispatcher diff-mode exec-path-from-shell ssh-deploy-hydra ssh-deploy
nginx-mode ac-html ac-html-core auto-complete-config auto-complete popup
ztree ztree-diff ztree-diff-model ztree-dir ztree-view ztree-util
gulp-task-runner grunt powerline powerline-separators powerline-themes
phpcbf php-auto-yasnippets php-mode add-log cc-langs php-face php
php-project mmm-mode mmm-univ mmm-class mmm-region mmm-auto mmm-vars
mmm-utils mmm-compat php-eldoc phps-mode derived phps-mode-tags
phps-mode-syntax-table phps-mode-semantic semantic/doc phps-mode-flymake
phps-mode-analyzer semantic/wisent semantic/wisent/wisent
phps-mode-wy-macros phps-mode-serial phps-mode-macros web-beautify w3m
doc-view jka-compr image-mode timezone w3m-hist w3m-fb bookmark-w3m
w3m-ems w3m-favicon w3m-image w3m-proc w3m-util hydra lv hl-line
auto-dictionary flyspell ispell editorconfig ansible-doc org-jira
org-jira-sdk jiralib request autorevert filenotify mail-utils
soap-client mm-decode mm-bodies mm-encode url-http url-auth mail-parse
rfc2231 rfc2047 rfc2045 mm-util ietf-drums mail-prsvr url-gw nsm rmc
puny rng-xsd rng-dt rng-util xsd-regexp xml org-clock ecb ecb-symboldef
ecb-analyse ecb-compatibility ecb-winman-support ecb-autogen autoload
radix-tree ecb-tod ecb-cycle ecb-eshell ecb-help ecb-jde
ecb-method-browser hideshow ecb-semantic-wrapper ecb-semantic
ecb-file-browser ecb-speedbar ecb-layout ecb-create-layout
ecb-compilation ecb-common-browser speedbar sb-image dframe ecb-navigate
eieio-compat ecb-mode-line ecb-face tree-buffer ecb-upgrade
ecb-cedet-wrapper semantic/db-find semantic/db-ref ecb-util which-key
csv-mode sort flycheck-package package-lint let-alist finder finder-inf
lisp-mnt flycheck flymake-rust flymake-easy flymake-proc flymake
rust-playground time-stamp cargo cargo-process smartparens-markdown
markdown-mode color smartparens-rust rust-mode image+ image-file
google-translate google-translate-default-ui google-translate-core-ui
google-translate-core google-translate-tk google-translate-backend url
url-proxy url-privacy url-expand url-methods url-history url-cookie
url-domsuf mailcap lorem-ipsum hyperbole hinit hibtypes hib-doc-id
hsys-www klink hib-kbd hib-social hib-debbugs hsys-org org-element
avl-tree smartparens-org org org-macro org-footnote org-pcomplete
org-list org-faces org-entities time-date org-version ob-emacs-lisp ob
ob-tangle org-src ob-ref ob-lob ob-table ob-keys ob-exp ob-comint
ob-core ob-eval org-compat org-macs org-loaddefs hactypes hui-mini hui
hui-mouse hmouse-key hargs hui-menu hyrolo-menu hyrolo hmail hui-jmenu
noutline outline hmouse-sh hmouse-drv hypb locate dired dired-loaddefs
hui-window hycontrol hsettings hui-em-but hbut hact hpath hhist hbdata
htz cal-julian cal-menu calendar cal-loaddefs hbmap hmoccur browse-url
hui-select hvar set hversion hload-path darktooth-theme autothemer
smartparens-config smartparens-javascript smartparens-text smartparens
paredit ripgrep thingatpt grep compile minimap skewer-mode cache-table
js2-mode etags fileloop generator xref project js cc-mode cc-fonts
cc-guess cc-menus cc-cmds cc-styles cc-align cc-engine cc-vars cc-defs
simple-httpd pp url-util doom-themes doom-themes-base base16-theme
dracula-theme with-editor warnings async-bytecomp async server yasnippet
yaxception ht dash know-your-http-well http-status-codes http-relations
http-methods http-headers s use-package up-delight up-diminish up-ensure
up-core pcase cl bind-key easy-mmode ido time winner elec-pair desktop
frameset recentf tree-widget wid-edit semantic/mru-bookmark
semantic/db-mode semantic/idle semantic/analyze semantic/sort
semantic/scope semantic/analyze/fcn semantic/db eieio-base
semantic/format ezimage semantic/ctxt semantic/decorate/mode
semantic/tag-ls semantic/find semantic/decorate pulse
semantic/util-modes semantic/util semantic semantic/tag semantic/lex
semantic/fw mode-local find-func cedet delsel battery disp-table
whitespace which-func imenu windmove tramp tramp-loaddefs trampver
tramp-integration files-x tramp-compat shell pcomplete comint ansi-color
ring parse-time ls-lisp format-spec wombat-theme edmacro kmacro
kotl-autoloads rx cl-extra help-mode advice w3m-load info package
easymenu epg-config url-handlers url-parse auth-source cl-seq eieio
eieio-core cl-macs eieio-loaddefs password-cache json subr-x map
url-vars seq byte-opt gv bytecomp byte-compile cconv cl-loaddefs cl-lib
tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel term/ns-win ns-win ucs-normalize mule-util term/common-win
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
cocoa ns multi-tty make-network-process emacs)

Memory information:
((conses 16 943870 51645)
(symbols 48 80255 3)
(strings 32 259884 5972)
(string-bytes 1 7562303)
(vectors 16 102296)
(vector-slots 8 1189521 55816)
(floats 8 832 297)
(intervals 56 7106 199)
(buffers 992 47))

-- 

Hälsningar / Best Regards
Christian

bug#39343: 27.0.50; Thrad signal crashes Emacs with sgmentation fault

[Alan Third]

On Wed, Jan 29, 2020 at 12:27:19PM +0100, Christian Johansson wrote:
> Running following works on Linux but not on macOS.
> 
> (let ((loop t)
>       (iterations 1))
>   (while loop
>     (make-thread
>      (lambda()
>        (message "Thread %d" iterations)
>        (signal 'error (list "My error"))))
>     (setq iterations (1+ iterations))))
> 
> Error in console: Fatal error 11: Segmentation faultAbort trap: 6
> 
> It seems to be some kind of issue with quitting threads on macOS which is
> not present on Linux

It’s a stack overflow caused by the main thread getting stuck in a
loop processing calls to ns_send_appdefined which must be coming from
the 2000‐odd threads the script starts.

Presumably it’s the call to ns_run_loop_break in sys_cond_broadcast
that’s doing it.

I don’t think there’s really any way round this other than the massive
rewrite the NS port needs to make it handle threads correctly.

-- 
Alan Third

bug#39343: 27.0.50; Thrad signal crashes Emacs with sgmentation fault

[Christian Johansson]

Hi

I understand, wish I had the skills to help with that but my C is weak and my macOS internals is even weaker.

Sometimes I get another thread issue on macOS. It also crashes Emacs but the error is something about try to clear a pointer that doesn’t point to anything anymore. Would it be helpful if I try to find a reproducable way of causing that and file another issue? It seems to occur non-determinstically so I haven’t been able to reproduce it yet. Could perhaps depend on garbage collector and maybe some kind of race-condition..

I have two plugins for Emacs that would improve significantly with stable thread support but at the moment it seems threads are unstable on macOS. I have not experienced any issues on Linux. Async.el works but it adds unecessary overhead by launching a separate Emacs process and it would be nice to not need it.

Kind regards
Christian

> 29 jan. 2020 kl. 21:42 skrev Alan Third <alan@idiocy.org>:
> 
>> On Wed, Jan 29, 2020 at 12:27:19PM +0100, Christian Johansson wrote:
>> Running following works on Linux but not on macOS.
>> 
>> (let ((loop t)
>>       (iterations 1))
>>   (while loop
>>     (make-thread
>>      (lambda()
>>        (message "Thread %d" iterations)
>>        (signal 'error (list "My error"))))
>>     (setq iterations (1+ iterations))))
>> 
>> Error in console: Fatal error 11: Segmentation faultAbort trap: 6
>> 
>> It seems to be some kind of issue with quitting threads on macOS which is
>> not present on Linux
> 
> It’s a stack overflow caused by the main thread getting stuck in a
> loop processing calls to ns_send_appdefined which must be coming from
> the 2000‐odd threads the script starts.
> 
> Presumably it’s the call to ns_run_loop_break in sys_cond_broadcast
> that’s doing it.
> 
> I don’t think there’s really any way round this other than the massive
> rewrite the NS port needs to make it handle threads correctly.
> 
> -- 
> Alan Third

bug#39343: 27.0.50; Thrad signal crashes Emacs with sgmentation fault

[Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Alan Third <alan@idiocy.org> writes:

> I don’t think there’s really any way round this other than the massive
> rewrite the NS port needs to make it handle threads correctly.

I don't understand the precise problem here (nor do I understand the
thread code.)  Could you elaborate on what the problem is, and why it
requires a massive rewrite?  Thanks.

NS port thread problems

[Alan Third]

On Wed, Oct 20, 2021 at 11:05:38AM +0800, Po Lu wrote:
> Alan Third <alan@idiocy.org> writes:
> 
> > I don’t think there’s really any way round this other than the massive
> > rewrite the NS port needs to make it handle threads correctly.
> 
> I don't understand the precise problem here (nor do I understand the
> thread code.)  Could you elaborate on what the problem is, and why it
> requires a massive rewrite?  Thanks.

macOS since, I think, 10.14 has required *ALL* GUI work to happen on
the main thread. This is a problem since, if you imagine running:

  (frame-set-width nil 100)

in a thread it will ultimately end up calling ns_set_window_size which
in turn will call "[window setFrame:frameRect display:NO]", which has
to be run in the main thread. ns_set_window_size also calls a number
of other GUI related methods, all of which need to run in the main
thread.

One solution would be to use Objective C "blocks" to run the code in
the main thread, but GCC doesn't support them, so that's out.

Another option is to use a "proxy" to send the messages to the main
thread. I know this works as I've written a proof of concept.

The main problem with that is that most of the functions we have that
will have to send method calls to the main thread have MANY method
calls, so that's a lot of back and forth to and from the main thread.
It seems to me that the better option is to try and simplify the code
so that ObjC classes provide the methods that the Emacsy C code
requires, rather than mixing it all together.

Additionally, I think even calling [NSView window] causes an error, so
any piece of code, that may run outside of the NS run loop, that
accesses an NSWindow MUST be sent to the main thread.

That's quite a lot of the C code in nsterm.

My ultimate plan, which I'm working towards very slowly, is to
introduce an EmacsFrame class that controls the EmacsViews and
EmacsWindows, and provides an API that matches roughly what the Emacs
side expects a frame to do. That's what most of my recent clean-up
work has been working towards.

I do not think that GNUstep has these limitations, so threads may not
be as prone to crash Emacs using it.
-- 
Alan Third

Re: NS port thread problems

[Po Lu]

Alan Third <alan@idiocy.org> writes:

> On Wed, Oct 20, 2021 at 11:05:38AM +0800, Po Lu wrote:

> macOS since, I think, 10.14 has required *ALL* GUI work to happen on
> the main thread. This is a problem since, if you imagine running:
>
>   (frame-set-width nil 100)

> in a thread it will ultimately end up calling ns_set_window_size which
> in turn will call "[window setFrame:frameRect display:NO]", which has
> to be run in the main thread. ns_set_window_size also calls a number
> of other GUI related methods, all of which need to run in the main
> thread.

> One solution would be to use Objective C "blocks" to run the code in
> the main thread, but GCC doesn't support them, so that's out.

I'm aware of this feature, but I don't understand how it will allow for
running code in the main thread.

> I do not think that GNUstep has these limitations, so threads may not
> be as prone to crash Emacs using it.

Interesting, thanks.

Re: NS port thread problems

[Alan Third]

On Thu, Oct 21, 2021 at 08:35:01AM +0800, Po Lu wrote:
> Alan Third <alan@idiocy.org> writes:
> 
> > One solution would be to use Objective C "blocks" to run the code in
> > the main thread, but GCC doesn't support them, so that's out.
> 
> I'm aware of this feature, but I don't understand how it will allow for
> running code in the main thread.

You can send a block off to run in another thread. Look up
dispatch_sync and friends.

-- 
Alan Third