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From Daniel Lescohier <daniel.lescoh...@cbsi.com>
Subject thread-safety of time conversion caches in util_time.c and mod_log_config.c
Date Fri, 04 Jan 2013 21:40:44 GMT
I entered a bug on the thread-safety of the time conversion caches in
server/util_time.c and modules/loggers/mod_log_config.c.

In brief, they're not thread-safe because:

   1. The algorithm depends on total memory ordering, and both the volatile
   qualifier and memory barriers are not used.
   2. The algorithm is subject to the "ABA problem."

The details of the problem are here:

https://issues.apache.org/bugzilla/show_bug.cgi?id=54363

I included in the bug not-yet-tested patches with a different algorithm.

Do other people agree that the existing algorithm have the problems
explained in detail in the bug?

Thanks,

Daniel Lescohier

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