Occasionally I see problems caused by Apache modules using per-process pools on a request processing thread. Aside from the thread-safety issues, they had no business doing that anyway.
It would be cool for the MPM to be able to lock the pool once it is ready to start serving requests so that if any errant module tries to use pconf, pchild, etc. it will crash immediately instead of introducing memory corruption under load. (Even if the module author is "clever" and uses a mutex around the pool use, that assumes she is the only person in the world to have that idea.) Some other multi-threaded APR apps probably have the same concern, especially if they allow plug-ins from third parties to be loaded. apr_pool_lock() - cause abort() on subsequent allocation request apr_pool_unlock() - allow it to be used again
