bug#56108: 29.0.50; ASAN use-after-free in re_match_2_internal

[Eli Zaretskii]

> Date: Fri, 24 Jun 2022 11:35:18 +0200
> From: Gerd Möllmann <gerd.moellmann@gmail.com>
> Cc: 56108@debbugs.gnu.org
> 
> Please find patch attached.
> 
> Some notes about the patch:
> 
> * TRT, I think, would be to change the whole cacheing to use Lisp objects 
> etc.  I couldn't persuade myself
>  to do that.
> * A less right thing, but better than the patch, would be to protect the 
> cache entry in re_match_2_internal. 
>  But that requires interface changes because re_match_2_internal currently 
> doesn't know about cash
>  entries.  I couldn't bring myself to do that either.

Good points.

Since there were no more comments, I've now installed this, and I'm
marking the bug done.

P.S. Gerd, please in the future try to remember to mention the bug
number in the commit log message.  (I added it this time, but I cannot
be trusted to catch that every time ;-)