Bug #78973 [Opn->Csd]: Destructor during CV freeing causes segfault if opline never saved

Edit report at https://bugs.php.net/bug.php?id=78973&edit=1 ID: 78973 Updated by: nikic@php.net Reported by: nikic@php.net Summary: Destructor during CV freeing causes segfault if opline never saved -Status: Open +Status: Closed Type: Bug Package: Scripting Engine problem PHP Version: 7.4Git-2019-12-16 (Git) Block user comment: N Private report: N New Comment: Automatic comment on behalf of nikita.ppv@gmail.com Revision: http://git.php.net/?p=php-src.git;a=commit;h=11b041d3c6f65ba7539c61edcf9587618af1ed43 Log: Fixed bug #78973 Previous Comments: ------------------------------------------------------------------------ [2019-12-16 17:45:13] nikic@php.net Description: ------------ If global regs are used, and during the execution of a function the opline is never stored, then a destructor call during CV freeing may result in a segfault when attempting to read the current opline in zend_call_function. ==20975== Use of uninitialised value of size 8 ==20975== at 0x91F333: zend_call_function (zend_execute_API.c:678) ==20975== by 0x9895DE: zend_objects_destroy_object (zend_objects.c:179) ==20975== by 0x990A30: zend_objects_store_del (zend_objects_API.c:178) ==20975== by 0x93489B: rc_dtor_func (zend_variables.c:57) ==20975== by 0x9A6C9C: i_free_compiled_variables (zend_execute.c:3407) ==20975== by 0xA10528: execute_ex (zend_vm_execute.h:53450) ==20975== by 0xA14ACB: zend_execute (zend_vm_execute.h:57669) ==20975== by 0x938F4A: zend_execute_scripts (zend.c:1665) ==20975== by 0x89B078: php_execute_script (main.c:2619) ==20975== by 0xA1769D: do_cli (php_cli.c:961) ==20975== by 0xA18807: main (php_cli.c:1352) In PHP 7.3 this did not happen, because EX(opline) was always written during execute_data initialization. However, the behavior may not have been exactly right, as the opline might still have been stale. Test script: --------------- <?php function test($x) { } test(new class { public function __destruct() { } }); ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=78973&edit=1