bug#39962: 27.0.90; Crash in Emacs 27.0.90

[Pieter van Oostrum]

Pip Cet <pipcet@gmail.com> writes:

> On Wed, Mar 18, 2020 at 11:38 AM Pieter van Oostrum
>> I have a procedure to generate a crash, but it isn't very predictable.
>> I think that is because there are timers running and asynchronous
>> processes. I get a different crash each time I run it.
>
> I think it's because of user interaction and the events it generates...

[
...
]
> Is it possible this is somehow related to mouse/keyboard interaction?
> That's my prime suspect, anyway; I still think that macOS runs code
> asynchronously upon receiving external events in ways that aren't
> kosher, particularly if they happen during GC.

I think that is quite probable.

I had my keyboard macro translated to an Elisp function and then called this a 
100 times with dotimes. However, there was no crash, even though I had the 
smaller stack size.

In total I had the macro run some 300+ times without any crash. I just had it 
run automatically (put it in a .el file, and used emacs -Q -l testfile.el), so 
no keyboard/mouse interaction.

> If I'm right, it should be possible to trigger the bug by creating a
> reasonably large session, running (garbage-collect) in an infinite
> loop, and interacting with the mouse and keyboard while that is
> happening. Or running your keyboard macro in a similar loop, of
> course.

But if I do it in a loop it will not react to the keyboard/mouse. Do you think 
the asynchronous processing of these events will be sufficient, even though no 
action is taken on these events?
-- 
Pieter van Oostrum
www: http://pieter.vanoostrum.org/
PGP key: [8DAE142BE17999C4]