Upgrading from Fedora 35 to Fedora 38 made the following changes: 
   Apache 2.4.54 -> Apache 2.4.57
   mod_perl 2.0.12 -> mod_perl 2.0.12 (no change)
   Perl 5.34.1 -> Perl 5.36.1

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I downgraded back to Apache 2.4.54 and mod_perl was still hanging when multiple mod_perl requests for the same cgi-script came in. mod_perl worked fine when a single cgi-script request came in by itself.

I attempted to roll back to Perl 5.34.1 and the dnf package manager wanted to roll back a huge number of rpms, so I looked for another solution. Perl 5.38.0 was released on July 3, 2023 and there is a Fedora 39 rpm available for that, so I upgraded to Perl 5.38.0 rpms on my test box and now mod_perl is working fine again with the existing codebase.

My guess is there was a defect in the THX_name_key() or THX_ck_rv2xv() routines in my environment that caused an infinite loop when simultaneous mod_perl requests hit the web server. A single mod_perl request worked fine. I have no way to confirm this definitively, it's just my humble opinion. I was unable to identify anything in the release notes for 5.38.0 that might have been the root cause. Maybe a deeper inspection into the source code might reveal the answer, however I am not really qualified to do that.

Thanks to the folks that took the time to respond to my post.

In reply to Re: mod_perl: Where can I find THX_name_key()? by seann
in thread mod_perl: Where can I find THX_name_key()? by seann

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