Re: [PHP4BETA] stack overflow in long running script. found the problem!

AI_COUNT is probably the flakiest part of Zend (it'll be fine once it's 100% stable, but we're only at around 99% stability right now). Calling any AI_COUNT macros is probably wrong, unless you really really know what you're doing. I'll need access to your machine in order to try and figure out what's wrong... About your piece of code, this piece of code may be problematic for Zend to handle, and may confuse the garbage collector into a situation where it would not free any hashes/objects until the method call ends. We decided that was an acceptable limitation, since you would rarely have a case that both 'stalls' the garbage collector, and also generates a considerable amount of garbage. Still, if that does happen, Zend's memory consumption will rise significantly. It should still not cause stability problems, unless you run out of memory. Zeev At 16:28 05/07/99 , Thies C. Arntzen wrote:

whua.... did some digging: zend_variables.c:85 pushes thingies on the "garbage" stack, which overflows! zend_execute does not call DEC_AI_COUNT() "often" enough! i helped myself by calling sometimg like "DEC_AI_COUNT" in zval_dtor - and it helped! which is what we call a "pfusch" in germany (hack would be a too positive word for this;-) so, please check if you forgot to call DEC_AI_COUNT somewhere BTW: the script in question does something like: $dok = new Dossier; while ($db->getrow()) { $dok->loadFromDB($db->getid()); // loadFromDB is ~300 lines of code!

        $dok->save();           // ~500 lines of code

} so maybe you forget to call your garbage-collector while just beeing in a loop? regards, tc On Mon, 5 Jul 1999, Thies C. Arntzen wrote: hi, this could be a tough one: a script that runs thru thousands of records (using classses etc) crashes after some time saying: FATAL: erealloc(): Unable to allocate -131072 bytes FATAL: erealloc(): Unable to allocate 0 bytes i traced it down to zend_ptr_stack_push and added a debug line like this:

    if (stack->top > 1000)
        fprintf(stderr, "> 0x%08x %d opcode %d on opline %d of %s() at %s:%d\n",
                stack,
                stack->top - 1,
                active_opline->opcode,
                active_opline-EG(active_op_array)->opcodes,
                get_active_function_name(),
                zend_get_executed_filename(ELS_C),
                zend_get_executed_lineno(ELS_C));

(dunno if the debug-output shows the correct script-line, but...) what i get is: .....

0x000e010c 8219 opcode 57 on opline 6 of _gettabletype() at

../../php/package/phpbasic/phpsite/functions/dossier.fnc:2368

0x000e010c 8220 opcode 57 on opline 6 of _gettabletype() at

../../php/package/phpbasic/phpsite/functions/dossier.fnc:2368

0x000e010c 8221 opcode 57 on opline 2078 of filtabexists() at

../../php/package/phpbasic/phpsite/functions/dossier.fnc:1220

0x000e010c 8222 opcode 58 on opline 12 of modify() at

../../php/package/phpbasic/phpsite/functions/dossier.fnc:556

0x000e010c 8223 opcode 58 on opline 12 of modify() at

../../php/package/phpbasic/phpsite/functions/dossier.fnc:556

0x000e010c 8224 opcode 58 on opline 12 of modify() at

../../php/package/phpbasic/phpsite/functions/dossier.fnc:556

0x000e010c 8225 opcode 58 on opline 12 of modify() at

../../php/package/phpbasic/phpsite/functions/dossier.fnc:556 .....

0x000e010c 16399 opcode 57 on opline 48 of _parse() at

../../php/package/phpbasic/phpsite/functions/dossier.fnc:1982

0x000e010c 16400 opcode 57 on opline 48 of _parse() at

../../php/package/phpbasic/phpsite/functions/dossier.fnc:1982

0x000e010c 16401 opcode 1515870810 on opline -60479576Segmentation

fault (core dumped) and so on - this stack is never ever popped, which causes the overflow & the crash. there's a lot of php code running - if you want i can get you access to one of my boxes! regards, tc

Thies C. Arntzen                 "One Big-Mac, Small Fries and a Coke!"
Digital Collections             Phone +49 40 235350 Fax +49 40 23535180
Hammerbrookstr. 93                              20097 Hamburg / Germany

-- PHP 4 Beta

Thies C. Arntzen                 "One Big-Mac, Small Fries and a Coke!"
Digital Collections             Phone +49 40 235350 Fax +49 40 23535180
Hammerbrookstr. 93                              20097 Hamburg / Germany

-- PHP 4 Beta

-- Zeev Suraski <zeev@zend.com> http://www.zend.com/ For a PGP public key, finger bourbon@netvision.net.il