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opcache.consistency_checks > 0 causes segfaults in PHP >= 8.1.5 in fpm context #8065

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opcache.consistency_checks > 0 causes segfaults in PHP >= 8.1.5 in fpm context#8065
Assignees
iluuu1994
Labels
BugExtension: opcacheStatus: Verified

Description

@CyberLine
CyberLine
opened on Feb 9, 2022

Description

After upgrading some projects to PHP 8.1.0 and 8.1.2 we could see requests getting slower and slower over time. Restart of the correspondig fpm-pool fixed that for short. After digging in the problem we could isolate and reproduce it:

  • use a Debian 10 or 11 maschine and install php8.1-fpm and php8.1-opcache.
  • modify opcache.ini:
zend_extension=opcache.so

[opcache]
opcache.consistency_checks=1
  • require laminas: composer require laminas/laminas-servicemanager
  • create a test script (we use laminas-servicemanager here):
<?php

declare(strict_types=1);

chdir(dirname(__DIR__));
require 'vendor/autoload.php';

use Laminas\ServiceManager\ServiceManager;
$container = new ServiceManager();
  • call that script in a loop 1000 or more times while running htop in another terminal:
    for i in {1..10000}; do curl localhost/test.php; done;

You would see an increment usage of memory that will not getting freed after all. Set opcache.consistency_checks to 0 to check that it will not keep any used memory.

PHP Version

8.1.0

Operating System

Debian 10/11

Activity

  1. CyberLine
    added
    Bug
    Status: Needs Triage
    on Feb 9, 2022

  2. cmb69 commented on Feb 9, 2022

    @cmb69
    cmb69
    on Feb 9, 2022
    Member

    Do you get any "Checksum failed for" log entries, if you set opcache.error_log=… and opcache.log_verbosity_level=4?

  3. cmb69
    added
    Status: Needs Feedback
    and removed
    Status: Needs Triage
    on Feb 9, 2022

  4. CyberLine commented on Feb 9, 2022

    @CyberLine
    CyberLine
    on Feb 9, 2022
    Author
    Wed Feb  9 15:15:47 2022 (222625): Message Checksum failed for '/home/alexander/test/vendor/laminas/laminas-config-aggregator/src/PhpFileProvider.php':  expected=0x68e34d40, found=0x35584fc2
Wed Feb  9 15:15:47 2022 (222625): Message Cached script '/home/alexander/test/vendor/laminas/laminas-config-aggregator/src/PhpFileProvider.php'
Wed Feb  9 15:15:47 2022 (222625): Message Added key '/home/alexander/test/vendor/composer/../laminas/laminas-config-aggregator/src/PhpFileProvider.php'
Wed Feb  9 15:15:47 2022 (222625): Message Checksum failed for '/home/alexander/test/vendor/laminas/laminas-servicemanager/src/ServiceManager.php':  expected=0x76daed23, found=0x478bef0e
Wed Feb  9 15:15:47 2022 (222625): Message Cached script '/home/alexander/test/vendor/laminas/laminas-servicemanager/src/ServiceManager.php'
Wed Feb  9 15:15:47 2022 (222625): Message Added key '/home/alexander/test/vendor/composer/../laminas/laminas-servicemanager/src/ServiceManager.php'
Wed Feb  9 15:15:47 2022 (222625): Message Checksum failed for '/home/alexander/test/vendor/laminas/laminas-servicemanager/src/ServiceLocatorInterface.php':  expected=0xb598eac3, found=0x7ae8ecda
Wed Feb  9 15:15:47 2022 (222625): Message Cached script '/home/alexander/test/vendor/laminas/laminas-servicemanager/src/ServiceLocatorInterface.php'
Wed Feb  9 15:15:47 2022 (222625): Message Added key '/home/alexander/test/vendor/composer/../laminas/laminas-servicemanager/src/ServiceLocatorInterface.php'
Wed Feb  9 15:15:47 2022 (222625): Message Checksum failed for '/home/alexander/test/vendor/container-interop/container-interop/src/Interop/Container/ContainerInterface.php':  expected=0x20efdca4, found=0x5182df08
Wed Feb  9 15:15:47 2022 (222625): Message Cached script '/home/alexander/test/vendor/container-interop/container-interop/src/Interop/Container/ContainerInterface.php'
Wed Feb  9 15:15:47 2022 (222625): Message Added key '/home/alexander/test/vendor/composer/../container-interop/container-interop/src/Interop/Container/ContainerInterface.php'
  5. github-actions
    added
    Status: Needs Triage
    and removed
    Status: Needs Feedback
    on Feb 9, 2022

  6. cmb69 commented on Feb 9, 2022

    @cmb69
    cmb69
    on Feb 9, 2022
    Member

    Thanks!

    If the checksum comparison fails, the file is compiled again, and the old oparray is not freed – that is by design, to avoid copying shared memory. As such, this doesn't look like a bug, but I wonder why the checksum comparison fails in the first place. Are these files modified during script execution?

  7. cmb69
    added
    Status: Needs Feedback
    and removed
    Status: Needs Triage
    on Feb 9, 2022

  8. CyberLine commented on Feb 9, 2022

    @CyberLine
    CyberLine
    on Feb 9, 2022
    Author

    Are these files modified during script execution?

    No, they aren't. You can run the same code on PHP 7.4 or 8.0 without "Checksum failed" error 🤷

    Same output with php7.4 or 8.0:

    Wed Feb  9 15:32:07 2022 (222628): Message Cached script '/home/alexander/test/vendor/laminas/laminas-servicemanager/src/ServiceManager.php'
Wed Feb  9 15:32:07 2022 (222628): Message Added key '/home/alexander/workspace/test/vendor/composer/../laminas/laminas-servicemanager/src/ServiceManager.php'
Wed Feb  9 15:32:07 2022 (222628): Message Cached script '/home/alexander/test/vendor/laminas/laminas-servicemanager/src/ServiceLocatorInterface.php'
Wed Feb  9 15:32:07 2022 (222628): Message Added key '/home/alexander/test/vendor/composer/../laminas/laminas-servicemanager/src/ServiceLocatorInterface.php'
Wed Feb  9 15:32:07 2022 (222628): Message Cached script '/home/alexander/test/vendor/psr/container/src/ContainerInterface.php'
Wed Feb  9 15:32:07 2022 (222628): Message Added key '/home/alexander/test/vendor/composer/../psr/container/src/ContainerInterface.php'
Wed Feb  9 15:32:07 2022 (222628): Message Cached script '/home/alexander/test/vendor/container-interop/container-interop/src/Interop/Container/ContainerInterface.php'
Wed Feb  9 15:32:07 2022 (222628): Message Added key '/home/alexander/test/vendor/composer/../container-interop/container-interop/src/Interop/Container/ContainerInterface.php'
  9. github-actions
    added
    Status: Needs Triage
    and removed
    Status: Needs Feedback
    on Feb 9, 2022
  10. cmb69
    removed
    Status: Needs Triage
    on Feb 9, 2022

  11. 34 remaining items

  12. ndossche
    added 3 commits that reference this issue on Mar 1, 2023

    Fix phpGH-8065: opcache.consistency_checks > 0 causes segfaults in PH…

    91e64af

    Disable opcache.consistency_checks

    9314ef8
  13. ndossche
    closed this as completedin 85df512on Mar 7, 2023
  14. ndossche
    added 2 commits that reference this issue on Mar 7, 2023

    Merge branch 'PHP-8.1' into PHP-8.2

    7682868

    Merge branch 'PHP-8.2'

    b39ff33
  15. ranvis
    added a commit that references this issue on Feb 3, 2024

    Fix phpGH-8065: opcache.consistency_checks > 0 causes segfaults in PH…

    85df512
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