Increase the PCRE JIT stack size #2910
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Related issues: https://bugs.php.net/bug.php?id=70110 https://bugs.exim.org/show_bug.cgi?id=1663 From the PCRE docs: **A maximum stack size of 512K to 1M should be more than enough for any pattern. ** https://www.pcre.org/original/doc/html/pcre_jit_stack_alloc.html This also affects applications all over the web that fail by the strange behaviour that `preg_` calls return errors for valid expressions. Some highlights: https://www.drupal.org/node/2792877
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See also a related discussion which happened on internals quite a while ago. |
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@cmb69 Thanks for the background. That discussion seems to have "died out" after one test regexp passed when increasing the stack limit to 64K, but this is far below the recommended maximum of 512K-1M. Coming from a developer standpoint, it's very scary to not be able to trust the result of |
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To me the worst part of the preg_ situation is they fail without warning or exception - you have to actually check That's… horrid. |
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The pattern @khromov regarding the Drupal issue you've linked, were it possible you to post some short reproduce code as it doesn't seem clear from the ticket and that patch isn't merged in Drupal. Thanks. |
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This issue seems to persist when running WordPress 5.0 and PHP 5.3.0. Are there are solutions besides disabling PCRE JIT via php.ini ? |
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@ettoredn You can't disable PCRE JIT in PHP 5.3.0, since it is only available as of PHP 7.0.0. |
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@ettoredn Yes, using something less ancient - PHP 7.3 currently has stack size limit of 192 MiB. |
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Sorry, that was a silly typo. I am experiencing the issue in PHP 7.3.0!
macOS 10.13.6, PHP 7.3.0, XDebug 2.7.0beta1 |
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@ettoredn That error does not look stack size related, it's an OOM during pattern compilation, not execution. Is it possible to reproduce this with an isolated code sample? |
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@ettoredn Also, please report this issue on bugs.php.net as well, I think this might be some PCRE2 related regression. |
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Thanks. I reported the issue https://bugs.php.net/bug.php?id=77260 |
Added 2 variables below which can be set in persistent config file. When enabled PHP_PCREJIT_STACKSIZE_ADJUST='y' and PHP_PCREJIT_STACKSIZE='512' are set in persistent config file /etc/centminmod/custom_config.inc prior to centmin.sh menu option 5 recompiles/updates, allows you to raise PHP's default PCRE JIT stack size php/php-src#2910 from current defaults which for PHP 7.2 is 64 x 1024 max and PHP 7.3 is 192 x 1024 max and PHP 7.4 is 256 x 1024 max. PHP_PCREJIT_STACKSIZE defines the value to raise to i.e. 512 x 1024 for PCRE_JIT_STACK_MAX_SIZE which is hard coded and set by PHP. Disabled by default PHP_PCREJIT_STACKSIZE_ADJUST='n'. PHP_PCREJIT_STACKSIZE_ADJUST='y' PHP_PCREJIT_STACKSIZE='512'
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I belive it can be closed, the stack size limit is now 192KB Line 59 in 3e01f5a |
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Right, I haven't heard about any stack size issues recently anymore, so I think the current 192KB size is sufficient. Let's reconsider if there are actual issues. |
Related issues:
https://bugs.php.net/bug.php?id=70110
https://bugs.exim.org/show_bug.cgi?id=1663
From the PCRE docs:
A maximum stack size of 512K to 1M should be more than enough for any pattern.
https://www.pcre.org/original/doc/html/pcre_jit_stack_alloc.html
This also affects applications all over the web that fail by the strange behaviour that
preg_calls return errors for valid expressions. Some highlights:https://www.drupal.org/node/2792877
Heroku have defaulted
pcre.jit = 0, presumably due to this issue.https://devcenter.heroku.com/changelog-items/853