[ft] System freeze when antialiasing is turned on

[Haakon Riiser]

I used to run Freetype with antialiasing disabled, since I prefer
the sharp rendering obtained when the bytecode hinter is enabled,
but I was getting fed up with Courier New for monospaced fonts, and
started looking for an alternative.  Unfortunately, I found nothing
that had decent hinting, so I decided to disable bytecode hinting
and start using antialiasing instead.  In the following hours,
X froze multiple times, something it had never done before.
At first, I wasn't sure what to blame; it didn't occur to me that
something as innocent as the antialiasing could cause it, until I
found a way to reproduce the hang with 100% accuracy.

All you need is a webpage with a lot of clean text, such as this,

  http://grid.uio.no/hrk/cdward.html

then start resizing the text up and down like crazy.  I found it
easiest to use Firefox for this, since you can resize by keeping
Ctrl pressed while scrolling the mouse wheel rapidly back and
forth.  It never takes me more than 5 seconds to make X freeze.
Once it happens, the mouse cursor can move around, but it can't
interact with anything.  My machine is still alive though;
I can log in remotely and kill X to restore control, but it's
impossible to do anything about it from my local keyboard/mouse,
since that's under X's control.

I tried using a couple of different fonts, such as Arial
and Bitstream Vera Serif, and it didn't make any difference:
Crashes no matter which font I use.  Here's my ~/.fonts.conf:

  <?xml version="1.0"?>
  <!DOCTYPE fontconfig SYSTEM "fonts.dtd">
  <fontconfig>
    <match target="font">
      <edit name="antialias" mode="assign">
       <bool>true</bool>
      </edit>
    </match>
  </fontconfig>

When I set "antialias" to false, I can never crash the system,
so it's perfectly clear that this option causes it.  I assume
it is the Freetype library that handles the antialiasing, even
though the above config file belongs to fontconfig, and that's
why I'm posting the bug report here.

My distro is Slackware 10.1, and the most relevant software
versions are:

  linux 2.6.11 (x86)
  fontconfig 2.2.3
  freetype 2.1.9
  x.org 6.8.2
  glibc 2.3.4
  gtk 2.6.7
  firefox 1.0.4
  mozilla 1.8a6

Can anyone but me reproduce this?  I found it strange that such
a critical and easily triggered problem would go unnoticed
(didn't find anything in the archives, nor Google Groups).

-- 
 Haakon