Codeigniter preg_replace（） - 编译失败：消息

Question

我发布了来自cleditor codeigniter ajax的5页docx数据。当数据传递给控制器​​时，它会发出警告信息：

A PHP Error was encountered

Severity: Warning

Message: preg_replace(): Compilation failed: regular expression is too large 
   at offset 65439

Filename: core/Security.php

Line Number: 641"

并且控制器端没有发布数据，如：

// displays nothing
echo $messageText=trim($this->input->post('composeMessage', TRUE));

我尝试在config.php中设置FALSE global_xss_filtering

$config['global_xss_filtering'] = FALSE;

但它不起作用。