PHP 8.5.5 for Windows (Non Thread Safe) consistently returns 500 Server Errors on IIS v10.

[amelsens]

Description

I use WordPress, and any website I visit gives me almost anytime Server Error 500.
php-cgi.exe crasht with 0xC0000005 in php8.dll
I don’t get that with PHP 8.5.4 or earlier versions for Windows.

PHP Version

PHP 8.5.5 Non Thread Safe (NTS) x64

Operating System

Windows 11 Pro & Windows Server 2022 with IIS v10 FastCGI

[shivammathur]

@amelsens
We have a known regression in 8.5.5 with JIT, if you have that enabled, it should be fixed by #21710

[amelsens]

PHP 8.5.5 crashes on Windows with IIS due to a bug in the JIT compiler
I discovered this whilst looking through all the information regarding the issues with PHP 8.5.5 on Windows.
Solution: set opcache.jit = disable and opcache.jit_buffer_size = 0 in the php.ini file, and comment out the other opcache.jit settings, of course.
PHP 8.5.5 no longer crashes on Windows for the time being. No more Server 500 Errors.

[shivammathur]

Closing as duplicate of #21368 (comment)

[amelsens]

In the meantime, I’ve discovered a much better option online. Especially if you’re using WordPress on a Windows OS with IIS as the web server.
Root cause: PHP JIT tracing builds a corrupted hot path through get_stylesheet() in wp-includes/theme.php over thousands of requests.
By excluding the "wp-includes/theme.php" file during the Opcache JIT compilation, you can prevent Opcache JIT from crashing.
This exclusion can be configured as follows in the php.ini file:
opcache.blacklist_filename= "C:\path\php-jit-blacklist.txt"
In this "php-jit-blacklist.txt" file, you can then specify the path where the "wp-includes/theme.php" files are located. For example: C:\path*\wp-includes\theme.php
I have tested this and it works. So Opcache JIT works again on Windows OS with IIS without crashing.
You can find more details on where I found this information at:
https://community.cyberpanel.net/t/verified-fix-php-8-5-x-jit-tracing-corruption-causing-4295229440-byte-allocation-wordpress/60651/1