Memory manager fast_cache_list_entry corruption

Running PHP as a servlet under Tomcat on AIX and I am getting a consistent segfault on the third call to jver.php. I've debugged to the point of identifying a corrupted fast_cache_list_entry. Specifically, while iterating through the while loop in shutdown_memory_manager (see below), I hit a fast_cache_list_entry whose next pointer points back to itself. efree is called multiple times on the same address which eventually results in a seg fault. Hoping someone more familier with the code may have some insite on where I might look for the bug. Thanks, Bill From zend_alloc.c... ZEND_API void shutdown_memory_manager(int silent, int clean_cache) { <snip> for (fci=0; fci<MAX_FAST_CACHE_TYPES; fci++) { fast_cache_list_entry = AG(fast_cache_list_head)[fci]; while (fast_cache_list_entry) { next_fast_cache_list_entry = fast_cache_list_entry->next; efree(fast_cache_list_entry); fast_cache_list_entry = next_fast_cache_list_entry; } }