# debugging PHP memory corruption

- Thread: https://externals.io/message/57253
- Original archive: https://news-web.php.net/php.internals/57253
- Started by Andrew Morum on 2012-01-06T15:36:28+00:00
- Messages: 2
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## #57253 — Andrew Morum — 2012-01-06T15:36:28+00:00

URL: https://externals.io/message/57253#57253

We've got a problem with PHP 5.3.8 and a third party (open source)
library (WSo2 SOAP).

 

At some point during the request to the PHP script, some structures seem
to be getting corrupted causing PHP to crash.

 

Depending on the code in the PHP script, it's either crashing during in
a print_r/var_export or crashing when the PHP shuts down (the exact
location of the crash moves around when we alter the code).

 

We can reprod this on Win32 and Linux now. But how can we go about
debugging where the corruption occurred? The address of the corrupted
data is not known until the segfault/access violation occurs so we can't
set a watch on it (as far as we can tell). 

 

Here's what we see in the debugger on Win32:

 

Unhandled exception at 0x1008eb45 (php5ts.dll) in php-cgi.exe:

Access violation reading location 0x4cac5400

 

php5ts.dll!_zval_ptr_dtor(_zval_struct * * zval_ptr=0x4cab5400)  + 0x5
bytes        

php5ts.dll!zend_hash_destroy(_hashtable * ht=0x034cc0f0)  + 0x27 bytes


php5ts.dll!zend_objects_free_object_storage(_zend_object *
object=0x03489fa0, void * * * tsrm_ls=0x003f42b0)  + 0x2b bytes    

php5ts.dll!zend_objects_store_free_object_storage(_zend_objects_store *
objects=0x003f685c, void * * * tsrm_ls=0x003f42b0)  + 0x9c bytes        

php5ts.dll!shutdown_executor(void * * * tsrm_ls=0x003f42b0)  + 0x2fe
bytes       

php5ts.dll!zend_deactivate(void * * * tsrm_ls=0x003f42b0)  + 0x91 bytes 

php5ts.dll!php_request_shutdown(void * dummy=0x00000000)  + 0x31f bytes


php-cgi.exe!main(int argc=1, char * * argv=0x003f31d0)  + 0xe89 bytes   

php-cgi.exe!__tmainCRTStartup()  + 0x10f bytes 

 

Any tips welcomed.

 

Andy.

 



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## #57254 — Ferenc Kovacs — 2012-01-06T15:41:54+00:00

URL: https://externals.io/message/57253#57254 · In reply to: #57253

> We've got a problem with PHP 5.3.8 and a third party (open source)
> library (WSo2 SOAP).
>
>
hi

Could you open a ticket on http://bugs.php.net and attach all the info that
you have about the problem.
If you could also attach a gdb backtrace following the steps on
https://bugs.php.net/bugs-generating-backtrace.php that would be really
useful.

Thanks for your report!

-- 
Ferenc Kovács
@Tyr43l - http://tyrael.hu