serialize segfault

Hi all, I'm trying to track down a segfault to do with serializing an object. I can't reproduce it with a small script so I'm not sure where to go from here. Any suggestions, tips, helpful hints greatly appreciated. It's part of a largish CMS which uses lots of circular references so pasting an example isn't easy. Here's a backtrace: (gdb) bt #0 0x4023d67e in php_var_serialize_class_name (buf=0xbffddf20, struc=0x8bd961c)

    at /usr/src/php-4.3.2/ext/standard/var.c:416
#1  0x4023c899 in php_var_serialize_class (buf=0xbffddf20, struc=0x8bd961c, retval_ptr=0x8b43dec, var_hash=0xbffddf30)
    at /usr/src/php-4.3.2/ext/standard/var.c:430
#2  0x4023cdf5 in php_var_serialize_intern (buf=0xbffddf20, struc=0x8bd961c, var_hash=0xbffddf30)
    at /usr/src/php-4.3.2/ext/standard/var.c:549
#3  0x4023d05b in php_var_serialize (buf=0xbffddf20, struc=0x8bd961c, var_hash=0xbffddf30)
    at /usr/src/php-4.3.2/ext/standard/var.c:623
#4  0x4023d108 in zif_serialize (ht=1, return_value=0x88340d4, this_ptr=0x0, return_value_used=1)
    at /usr/src/php-4.3.2/ext/standard/var.c:646
#5  0x402c8947 in execute (op_array=0x8cb5da4) at /usr/src/php-4.3.2/Zend/zend_execute.c:1606

(gdb) frame 5 #5 0x402c8947 in execute (op_array=0x8cb5da4) at /usr/src/php-4.3.2/Zend/zend_execute.c:1606 1606 ((zend_internal_function *) EX(function_state).function)->handler(EX(opline)->extended_value, EX(Ts)[EX(opline)->result.u.var].var.ptr, EX(object).ptr, return_value_used TSRMLS_CC); (gdb) print (char *)(executor_globals.function_state_ptr->function)->common.function_name $1 = 0x4030831b "serialize" $ gcc -v Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/2.96/specs gcc version 2.96 20000731 (Red Hat Linux 7.3 2.96-113) Can anyone give me a hand with tracking down the problem? Thanks! Chris.