bug#18339: 24.4.50; Inserting '$' in TeX-mode cause Emacs crashed in MS-Windows with trunk.

[Eli Zaretskii]

> Date: Thu, 28 Aug 2014 13:07:21 +0800
> From: Chris Zheng <chriszheng99@gmail.com>
> 
> From: Eli Zaretskii <eliz@gnu.org>
> Subject: Re: bug#18339: 24.4.50; Inserting '$' in TeX-mode cause Emacs 
> crashed in MS-Windows with trunk.
> Date: Wed, 27 Aug 2014 22:46:16 +0300
> 
> > Thanks, I fixed this in trunk revision 117752.
> 
> I confirmed that this bug is fixed in trunk.  Thank you!  Is this
> change backport to 24.4 branch?  I think the same problem is in
> pretest of 24.4, too.

I installed in the trunk because I couldn't reproduce the problem in
the emacs-24 branch.  But you are right: the same faulty code is on
the branch, so I now backported the fix there (r117463).

> Also I'm quite curious why the bug wasn't found for a long period of
> time.

The buggy code examines memory 1 byte before an allocated buffer, so
the chance of that being outside the program's address space is
evidently quite small.

Memory management on Windows changed dramatically between emacs-24
branch and the trunk, so I guess this is the main reason that the bug
was exposed.