Description:
------------
We encountered a problem in one of our applications which ended in a segmentation fault/zend_mm_heap corrupted errors in our log files.

We tracked it down to an issue with serializing/deserializing SplObjectStorage objects and the garbadge collector. The test script make use of thousands of objects but in our application we used only some hands full of objects. Sadly we were not able to extract these logic into a smal code but the following test script should show the same behaviour.

We could reproduce the error in several PHP versions (since 5.4) and also run it on http://3v4l.org/tUoUf which showed the same problem for PHP 5.4.0 up to 5.6.6.

After all the segmentation fault does not arise if we disable the garbage collector with gc_disable().

Test script:
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<?php
// gc_disable(); // <-- if this comment is removed, everything works as expected

$a = array();
$b = new SplObjectStorage();
for ($i = 10000; $i > 0; $i--) {
    $object = new StdClass();
    $a[] = $object;
    $b->attach($object);
}

$c = serialize(array($a, $b));
$d = unserialize($c);

echo "ok";


Expected result:
----------------
ok

Actual result:
--------------
See http://3v4l.org/tUoUf