Subject: bug#61896: 30.0.50; Emacs crashes because of an invalid free

From: Mattias Engdegård <[email-masked]>
Date: Thu, 2 Mar 2023 16:21:12 +0100

> These checks do not audit the specpdl balance directly but that would be something to add if you don't make further progress.

You could try this patch if you build with --enable-checking=all: