Bug #77751 [NEW]: Writing to SplFileObject in ob_start gives segfault

From: michael dot mauch at gmx dot de Operating system: Ubuntu 16.04 PHP version: 7.3.3 Package: Output Control Bug Type: Bug Bug description:Writing to SplFileObject in ob_start gives segfault Description: ------------ I'm using a function like below to redirect all output to a log file in PHP CLI scripts. It works until PHP 7.1, but crashes with SIGSEGV in 7.2 and 7.3. If I use old fopen() instead of SplFileObject, it also works with 7.2 and 7.3. Oracle Linux 7.x at work, Ubuntu 16.04 at home, or even in docker with the official images. Test script: --------------- <?php $logfilename = "/tmp/crash.log"; $logfile = new SplFileObject($logfilename, "w"); ob_start(function ($buffer) use ($logfile) { $logfile->fwrite($buffer); $logfile->fflush(); return ""; }); echo "hmm\n"; Expected result: ---------------- # Like with PHP 7.1: % docker run -it --rm -v "$PWD":/tmp -w /tmp php:7.1-cli /bin/bash -c 'ulimit -c unlimited; php -v; php ./crash.php && echo ok' PHP 7.1.27 (cli) (built: Mar 9 2019 02:51:22) ( NTS ) Copyright (c) 1997-2018 The PHP Group Zend Engine v3.1.0, Copyright (c) 1998-2018 Zend Technologies ok Actual result: -------------- # But with PHP 7.3: % docker run -it --rm -v "$PWD":/tmp -w /tmp php:cli /bin/bash -c 'ulimit -c unlimited; php -v; php ./crash.php && echo ok' PHP 7.3.3 (cli) (built: Mar 9 2019 00:27:53) ( NTS ) Copyright (c) 1997-2018 The PHP Group Zend Engine v3.3.3, Copyright (c) 1998-2018 Zend Technologies /bin/bash: line 1: 7 Segmentation fault (core dumped) php ./crash.php -- Edit bug report at https://bugs.php.net/bug.php?id=77751&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=77751&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=77751&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=77751&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=77751&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=77751&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=77751&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=77751&r=needscript Try newer version: https://bugs.php.net/fix.php?id=77751&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=77751&r=support Expected behavior: https://bugs.php.net/fix.php?id=77751&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=77751&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=77751&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=77751&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=77751&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=77751&r=dst IIS Stability: https://bugs.php.net/fix.php?id=77751&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=77751&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=77751&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=77751&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=77751&r=mysqlcfg