Bug #76711 [Ver->Csd]: OPcache enabled triggers false-positive "Illegal string offset"

Edit report at https://bugs.php.net/bug.php?id=76711&edit=1 ID: 76711 Updated by: dmitry@php.net Reported by: nicolas dot grekas+php at gmail dot com Summary: OPcache enabled triggers false-positive "Illegal string offset" -Status: Verified +Status: Closed Type: Bug Package: opcache PHP Version: 7.3Git-2018-08-06 (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=b8ffa3707c07e6edbe5db5a3fdf5516ba1f6bef0 Log: Fixed bug #76711 (OPcache enabled triggers false-positive &quot;Illegal string offset&quot;) Previous Comments: ------------------------------------------------------------------------ [2018-09-20 07:58:19] nikic@php.net Here is a simple reproduce (under valgrind): <?php function test($foo) { var_dump(0); var_dump($foo[0]); } test("str"); ------------------------------------------------------------------------ [2018-09-20 07:56:10] nikic@php.net Valgrind says: ==5806== Conditional jump or move depends on uninitialised value(s) ==5806== at 0xA652CA: ZEND_FETCH_DIM_R_INDEX_SPEC_CV_CONST_HANDLER (zend_vm_execute.h:41973) ==5806== by 0xA7D01D: execute_ex (zend_vm_execute.h:59659) ==5806== by 0xA7E0D5: zend_execute (zend_vm_execute.h:60703) ==5806== by 0x9A3D55: zend_execute_scripts (zend.c:1562) ==5806== by 0x90A5A8: php_execute_script (main.c:2636) ==5806== by 0xA80E2A: do_cli (php_cli.c:997) ==5806== by 0xA81FA0: main (php_cli.c:1390) This is likely a bug in literal compaction. It probably combines two integer literals, one with Z_EXTRA=0 and one with unspecified Z_EXTRA. The unspecified Z_EXTRA is then used in FETCH_DIM_R_INDEX. ------------------------------------------------------------------------ [2018-09-20 06:47:25] nicolas dot grekas+php at gmail dot com This issue still exists in 7.3.0RC1, see failures at https://travis-ci.org/nicolas-grekas/symfony/builds/430883587 ------------------------------------------------------------------------ [2018-08-07 07:28:57] laruence@php.net I can not reproduce this, what I got is: $ /home/huixinchen/local/php73/bin/php -d opcache.enable_cli=1 -d error_reporting=-1 -d display_errors=1 ./phpunit src/Symfony/Component/BrowserKit #!/usr/bin/env php PHPUnit 6.5.10 by Sebastian Bergmann and contributors. Testing src/Symfony/Component/BrowserKit .............................................F................. 63 / 136 ( 46%) ............................................................... 126 / 136 ( 92%) .......... 136 / 136 (100%) Time: 691 ms, Memory: 4.00MB There was 1 failure: 1) Symfony\Component\BrowserKit\Tests\ClientTest::testFollowMetaRefresh with data set #7 ('<html><head><noscript><meta h.../html>', 'http://www.example.com/redirected') Failed asserting that two strings are equal. --- Expected +++ Actual @@ @@ -'http://www.example.com/redirected' +'http://www.example.com/foo/foobar' /home/huixinchen/opensource/github/symfony/src/Symfony/Component/BrowserKit/Tests/ClientTest.php:669 /home/huixinchen/opensource/github/symfony/.phpunit/phpunit-6.5/phpunit:5 FAILURES! Tests: 136, Assertions: 312, Failures: 1. ------------------------------------------------------------------------ [2018-08-06 14:08:38] nicolas dot grekas+php at gmail dot com Description: ------------ when running the Symfony test suite on PHP 7.3 with opcache.enable_cli=1, some tests fail with "Illegal string offset '...'" errors, which make no sense: Example build is: https://travis-ci.org/nicolas-grekas/symfony/builds/411802579#L2508 The reported line reads as such: > if (!$uri || '#' == $uri[0] || '?' == $uri[0]) { See https://github.com/symfony/symfony/blob/master/src/Symfony/Component/BrowserKit/Client.php#L668 It looks like there is a leak from L649 to L668: https://github.com/symfony/symfony/blob/master/src/Symfony/Component/BrowserKit/Client.php#L649 Test script: --------------- No better reproducer sorry: git clone https://github.com/symfony/symfony cd symfony composer install ./phpunit install php -dopcache.enable_cli=1 ./phpunit src/Symfony/Component/BrowserKit ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=76711&edit=1