segfault in shutdown sequence

I'm getting a segfault at the end of (successful) script execution. Appears to be an issue in the shutdown sequence; I'm unsure how to report this bug, since providing duplicating code is not possible. The segfault is happening at the end of a Phing (http://phing.info) build process, which involves many (over a hundred, I'm sure) classes, uses reflection api heavily, XML (expat), etc. Here's a bugtrace from the core file. I don't know if this is any help at all. I was hoping to find some 'execute' lines so I could track down the issue in my code. This seems to be just part of the shutdown sequence, though. If anyone has some suggestions for things I could look for, please let me know. Thanks, Hans #0 0x0818e625 in zend_mm_remove_from_free_list (heap=0x81f7a80, mm_block=0xbed43144)

    at /home/work/php-5.0.0b4/Zend/zend_mm.c:163

#1 0x0818e158 in zend_mm_free (heap=0x81f7a80, p=0xbed434b0)

    at /home/work/php-5.0.0b4/Zend/zend_mm.c:356
#2  0x0816bf79 in _efree (ptr=0x3) at /home/work/php-5.0.0b4/Zend/zend_alloc.c:283

#3 0x0818bc50 in zend_objects_free_object_storage (object=0xbed44fec)

    at /home/work/php-5.0.0b4/Zend/zend_objects.c:78

#4 0x0818e94e in reflection_free_objects_storage (object=0xbed44fec)

    at /home/work/php-5.0.0b4/Zend/zend_reflection_api.c:191

#5 0x0818da3c in zend_objects_store_del_ref (zobject=0x3)

    at /home/work/php-5.0.0b4/Zend/zend_objects_API.c:140

#6 0x0817c1d1 in _zval_dtor (zvalue=0xbed443e4)

    at /home/work/php-5.0.0b4/Zend/zend_variables.c:61

#7 0x08174f79 in _zval_ptr_dtor (zval_ptr=0xbed48798)

    at /home/work/php-5.0.0b4/Zend/zend_execute_API.c:359

#8 0x08182da0 in zend_hash_destroy (ht=0xbedae214)

    at /home/work/php-5.0.0b4/Zend/zend_hash.c:513

#9 0x0817c1fd in _zval_dtor (zvalue=0xbedafc14)

    at /home/work/php-5.0.0b4/Zend/zend_variables.c:52

#10 0x08174f79 in _zval_ptr_dtor (zval_ptr=0xbed46430)

    at /home/work/php-5.0.0b4/Zend/zend_execute_API.c:359

#11 0x08182da0 in zend_hash_destroy (ht=0xbed44324)

    at /home/work/php-5.0.0b4/Zend/zend_hash.c:513

#12 0x0818bc47 in zend_objects_free_object_storage (object=0xbedac1cc)

    at /home/work/php-5.0.0b4/Zend/zend_objects.c:77

#13 0x0818d878 in zend_objects_store_free_object_storage (objects=0x81f7f70)

    at /home/work/php-5.0.0b4/Zend/zend_objects_API.c:71

#14 0x08174d90 in shutdown_executor ()

    at /home/work/php-5.0.0b4/Zend/zend_execute_API.c:273
#15 0x0817d4ec in zend_deactivate () at /home/work/php-5.0.0b4/Zend/zend.c:813

#16 0x0814cd9b in php_request_shutdown (dummy=0x0)

    at /home/work/php-5.0.0b4/main/main.c:1243

#17 0x081a13bf in main (argc=9, argv=0xbff651c4)

    at /home/work/php-5.0.0b4/sapi/cli/php_cli.c:1044