Php 7.0.19 call to undefined function exception despite defined

[kalyanceg]

Hi
This issue happens at apache2.4 running Debian 9.0 php7.0.19-1 is added as modphp. The issue appears only when Apache runs for a week or more. Things are fine usually less than a week. Call to undefined function exceptions start appearing for variable percentage of requests and the exception can be reproduced for those requests till Apache is restarted or opcache is reset. Once Apache is restarted or opcache is reset things work fine. Interned string buffer is observed to be full during the issue. As per documentation even if the interned buffer is full workers should use their own memory and degradation in performance might be possible. It looks an issue in interned string buffer as defined function names are missed.