Re: zend memory managment null pointer dereference

On 10/03/2011 11:42 PM, Chester, Alan wrote:

Hi, I have recently seen httpd core dump on my system. After looking into this issue it is the php module which is actually core dumping more specifically the zend memory management part of php. #0 0x0115d224 in zend_mm_remove_from_free_list (heap=0x99596e8,

     p=<value optimized out>)
     at /scratchpad/workdirs/ssilva/build/RPM/BUILD/php-5.2.17/Zend/zend_alloc.c:837

This is the worst kind of segfault since GDB backtrace doesn't carry any useful information in this case, it just tells us that the crash has happened at the request shutdown. But the real problem that caused the crash has occurred somewhere during the request and there's no way to know when & where basing on the backtrace only. I'd suggest to try reproducing this problem with Valgrind: https://bugs.php.net/bugs-getting-valgrind-log.php, this would give us a lot more info. -- Wbr, Antony Dovgal --- http://pinba.org - realtime profiling for PHP