Bug #69446 [Asn->Csd]: GC leak relating to removal of nested data after dtors run

Edit report at https://bugs.php.net/bug.php?id=69446&edit=1 ID: 69446 Updated by: dmitry@php.net Reported by: nikic@php.net Summary: GC leak relating to removal of nested data after dtors run -Status: Assigned +Status: Closed Type: Bug Package: Scripting Engine problem PHP Version: master-Git-2015-04-14 (Git) Assigned To: dmitry Block user comment: N Private report: N New Comment: Automatic comment on behalf of dmitry@zend.com Revision: http://git.php.net/?p=php-src.git;a=commit;h=00445ba22dd97988009692e2b35edaeff715f5e1 Log: Fixed bug #69446 (GC leak relating to removal of nested data after dtors run) Previous Comments: ------------------------------------------------------------------------ [2015-04-14 14:02:48] nikic@php.net Description: ------------ This issue is only obvious when freeing of the object store is disabled - otherwise the leaks will be hidden. Here is a patch to disable it: https://gist.github.com/nikic/2ccbc61c407d5e807781 The following script will leak: <?php $bar = NULL; class bad { public function __destruct() { global $bar; $bar = $this; $bar->y = new stdClass; } } $foo = new stdClass; $foo->foo = $foo; $foo->bad = new bad; $foo->bad->x = new stdClass; unset($foo); gc_collect_cycles(); The following script will also leak: <?php $bar = NULL; class bad { public $_private = array(); public function __construct() { $this->_private[] = 'php'; } public function __destruct() { global $bar; $bar = $this; } } $foo = new stdclass; $foo->foo = $foo; $foo->bad = new bad; unserialize(serialize($foo)); //unset($foo); gc_collect_cycles(); var_dump($bar); I have not been able to figure out how to stop the leak in both cases. The fundamental issue seems to be that gc_remove_nested_data does not decrement the refcount to compensate the incref that occurs in gc_collect_roots. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=69446&edit=1