Bastien <bzg@gnu.org> writes:

> Hi Eric,
>
> Eric Abrahamsen <eric@ericabrahamsen.net> writes:
>
>> After Nicolas made the last round of improvements to the caching
>> mechanism I got far fewer hangs with Org, but they are still happening.
>> Maybe once a day or so, on average, editing something in an Org buffer
>> causes emacs to hang, and my fans to spin up, and there we are until I
>> kill emacs.
>
> I've seen hiccups here and there, but generally, what happens is an
> error, not an infinite hanging.
>
>> It happens often enough that I guess it's worth running emacs under some
>> kind of debugger -- at least, I assume that's the best way of catching
>> the bug. I'm not really sure how to go hunting, though, so if anyone had
>> any advice in this direction, that would be great.
>
> I'd hunt for some infloop in parsing -- but cannot detail more than
> that, problably Nicolas could.
>
>> In the meantime, is there any way of interrupting emacs so it quits
>> whatever its doing, without having to kill it? I've played around with
>> sending different signals using "kill", just for fun, but everything
>> I've tried either does nothing, or kills emacs altogether.
>
> I have no suggestion here either, sorry :/

I have also semi-regular lockup with org-mode. I have opened a bug on
debbugs and here is what Stefan told me to try to debug this:

> You can try `debug-on-event'.
> 
> There's jit-lock-debug-mode but it doesn't disable inhibit-quit.
> So you'll need to additionally use
> 
>    (advice-add 'jit-lock--debug-fontify :around
>      (lambda (fun &rest args)
>        (with-local-quit (apply fun args))))
> 
> Of course sometimes this doesn't work because jit-lock-debug-mode
> changes the way things are executed and the bug may not manifest itself
> any more, but it's worth a try.
> 
> Another source of info is to
> 
>   M-x trace-function RET org-adaptive-fill-function RET
>   M-x trace-function RET org-element-at-point RET
>   M-x trace-function RET org-element--cache-sync RET
>   M-x trace-function RET org-element--cache-process-request RET
> 
> Then reproduce the hang, then break the hang somehow (maybe with the
> jit-lock-debug hack above, or maybe with debug-on-event, or with C-g C-g
> C-g, ...), then look at the *trace..* buffer.

I'll try to see what I can find this week end and report back.

By the way, if you want to see in which part the infloop occurs, you can
attach a gdb debugger to the running emacs, source the
<path-to-emacs-source>/src/.gdbinit file and use the `xbacktrace' command.

$ gdb <path-to-emacs-executable> <emacs-pid>
gdb) source <path-to-emacs-source>/src/.gdbinit
...
gdb) xbacktrace

You can also use the `bt' command but it contains much more noise.

-- 
Daimrod/Greg