Description:
------------
I have spent about 3 hours (!) trying to localize this crash and write simple script to reproduce it - but vainly. :-(

So, I write something that I have. The following code:

function reloadPlugins() {  
  #$s =& $this->smarty;
  $this->smarty->plugins_dir1 = array(1,2,3);
  foreach ($this->smarty->plugins_dir1 as $dir) {}
  debug_backtrace();
  return;
  // ..
}

reproducibly crashes PHP (General Protection Fault). 

* If I simply uncomment the first line (no more changes!), crash dissapears, all works. 

* When I use
  $s = $this->smarty;
  foreach ($s->plugins_dir1 ...)
it also works. 

* When I substitute Smarty with my own stub class (empty), it also works. 

* When I completely delete empty forech, all work fine. 

* And, of course, if I delete debug_backtrace() call, it works.

* PHP5 RC2 also works.

I don't know what is it, and I don't know how to catch it. But it exists. Sorry.