httpd: segmentation fault (GDB)

During one of my php programming, I encountered a httpd segmentation fault. The error was shown in error_log.

[root@fc21 ~]# tail -f /var/log/httpd/error_log

[Fri Jan 09 08:31:50.859976 2015] [core:notice] [pid 6757] AH00052: child pid 6775 exit signal Segmentation fault (11)

I decided to use GDB to see where the segmentation fault occur.

[root@fc21 ~]# systemctl stop httpd
[root@fc21 ~]# systemctl status httpd

To start GDB.

[root@fc21 ~]# gdb httpd
(gdb) r -DONE_PROCESS
Program received signal SIGSEGV, Segmentation fault.
0x00007fffe7f431e8 in _zend_mm_free_int () from /etc/httpd/modules/libphp5.so

And it displayed the fault occured in zend_mm_free_int. Proceed with a "where".

(gdb) where
#0  0x00007fffe7f431e8 in _zend_mm_free_int ()
   from /etc/httpd/modules/libphp5.so
#1  0x00007fffe7f629ce in convert_to_double ()
   from /etc/httpd/modules/libphp5.so
#2  0x00007fffe0d20ea1 in zif_trader_stoch (ht=,
    return_value=0x7ffff7f257f8, return_value_ptr=,
    this_ptr=, return_value_used=)
    at /root/trader-0.3.0/functions/trader_stoch.c:67
#3  0x00007fffe7f5bf2a in dtrace_execute_internal ()
   from /etc/httpd/modules/libphp5.so
#4  0x00007fffe8019800 in zend_do_fcall_common_helper_SPEC ()
   from /etc/httpd/modules/libphp5.so
#5  0x00007fffe7fa9dd0 in execute_ex () from /etc/httpd/modules/libphp5.so
#6  0x00007fffe7f5bdc8 in dtrace_execute_ex ()
   from /etc/httpd/modules/libphp5.so
#7  0x00007fffe7f6e7c0 in zend_execute_scripts ()
   from /etc/httpd/modules/libphp5.so
#8  0x00007fffe7f0a6cb in php_execute_script ()
   from /etc/httpd/modules/libphp5.so
#9  0x00007fffe801b3c2 in php_handler () from /etc/httpd/modules/libphp5.so
#10 0x00005555555942f0 in ap_run_handler ()
#11 0x0000555555594839 in ap_invoke_handler ()
#12 0x00005555555a966a in ap_process_async_request ()

To continue, enter "cont".

(gdb) cont
Continuing.

Program terminated with signal SIGSEGV, Segmentation fault.

GDB is a useful tool to identify where fault lies. Maybe you could be one to raise a bug in php/httpd/linux with this. And for this problem, I actually found out that I need to cast a decimal in a php variable.

array_push($high,number_format($obj["high"],2,'.',''));