bug#58042: 29.0.50; ASAN use-after-free in re_match_2_internal

["Gerd Möllmann" <gerd.moellmann@gmail.com>]

Eli Zaretskii <eliz@gnu.org> writes:

> So I guess we should do this dance around calls to maybe_quit in
> regex-emacs.c:
>
>   specpdl_ref gc_count = inhibit_garbage_collection ();
>   maybe_quit ();
>   unbind_to (gc_count, Qnil);
>
> Or maybe even better, do this inside probably_quit (because who knows
> how many other callers of maybe_quit could be hit by this unexpected
> GC)?
>
> Can you try this?

Isn't the -[EmacsView layoutSublayersOfLayer:] the problem?  AFAICT from
a web search, this is an event handler method that is also called from
by the framework?

In the olden days, it was a serious error to call into Lisp from an
event handler.  All bets were off when that happened, not only related
to GC.  I believe that hasn't changed much.

That code was introduced by Alan around this time.

1ba02d85a964e1b2c6a9735cd3decdc524e06dc1
Author:     Alan Third <alan@idiocy.org>
AuthorDate: Sat Jun 12 10:25:47 2021 +0100
Commit:     Alan Third <alan@idiocy.org>
CommitDate: Sat Jul 31 11:13:05 2021 +0100

Maybe Allen can say something, I've CC'd him.

Or maybe we should add your fix, too?