From: checat at yandex dot ru
Operating system: RHEL4
PHP version: 4.4.4
PHP Bug Type: Reproducible crash
Bug description: double free on circular references
Description:
------------
When freeing array variables with multiple references, variables which
should still be accessible via other reference may be unexpectedly freed.
Depending of the code it may produce data corruption, glibc-detected
memory corruption or segfault.
Reproduce code:
---------------
<?php
$root=array('id'=>'1', 'parent_id'=>NULL);
$child1 = array('id'=>'2', 'parent_id'=>'1');
// build tree with references up and down
$root['childs'] = array();
$child1['parent'] = & $root;
$child1['parent']['childs'][] = & $child1;
$child1['childs'] = array();
print_r($root['childs'][0]['childs']);
unset($child1);
print_r($root['childs'][0]['childs']);
?>
Expected result:
----------------
Array
(
)
Array
(
)
Actual result:
--------------
CGI:
Array
(
)
Array
(
)
Segmentation fault
Apache2/prefork/mod_php: no output, Segmentation fault in log
--
Edit bug report at http://bugs.php.net/?id=39046&edit=1
--
Try a CVS snapshot (PHP 4.4):
http://bugs.php.net/fix.php?id=39046&r=trysnapshot44
Try a CVS snapshot (PHP 5.2):
http://bugs.php.net/fix.php?id=39046&r=trysnapshot52
Try a CVS snapshot (PHP 6.0):
http://bugs.php.net/fix.php?id=39046&r=trysnapshot60
Fixed in CVS: http://bugs.php.net/fix.php?id=39046&r=fixedcvs
Fixed in release:
http://bugs.php.net/fix.php?id=39046&r=alreadyfixed
Need backtrace: http://bugs.php.net/fix.php?id=39046&r=needtrace
Need Reproduce Script: http://bugs.php.net/fix.php?id=39046&r=needscript
Try newer version: http://bugs.php.net/fix.php?id=39046&r=oldversion
Not developer issue: http://bugs.php.net/fix.php?id=39046&r=support
Expected behavior: http://bugs.php.net/fix.php?id=39046&r=notwrong
Not enough info:
http://bugs.php.net/fix.php?id=39046&r=notenoughinfo
Submitted twice:
http://bugs.php.net/fix.php?id=39046&r=submittedtwice
register_globals: http://bugs.php.net/fix.php?id=39046&r=globals
PHP 3 support discontinued: http://bugs.php.net/fix.php?id=39046&r=php3
Daylight Savings: http://bugs.php.net/fix.php?id=39046&r=dst
IIS Stability: http://bugs.php.net/fix.php?id=39046&r=isapi
Install GNU Sed: http://bugs.php.net/fix.php?id=39046&r=gnused
Floating point limitations: http://bugs.php.net/fix.php?id=39046&r=float
No Zend Extensions: http://bugs.php.net/fix.php?id=39046&r=nozend
MySQL Configuration Error: http://bugs.php.net/fix.php?id=39046&r=mysqlcfg
