(gdb) bt
#0  0x00000000006e8287 in zval_delref_p (pz=<optimized out>) at /build/php5-5.6.30+dfsg/Zend/zend.h:411
#1  i_zval_ptr_dtor (zval_ptr=0xc4058258) at /build/php5-5.6.30+dfsg/Zend/zend_execute.h:76
#2  _zval_ptr_dtor (zval_ptr=0x7f0358277888) at /build/php5-5.6.30+dfsg/Zend/zend_execute_API.c:424
#3  0x0000000000707ae8 in zend_hash_destroy (ht=0x7f035af416b0) at /build/php5-5.6.30+dfsg/Zend/zend_hash.c:548
#4  0x00000000006f80ab in _zval_dtor_func (zvalue=0x7f0358277888, zvalue@entry=0xbbd91a08) at /build/php5-5.6.30+dfsg/Zend/zend_variables.c:45
#5  0x00000000006e82d0 in _zval_dtor (zvalue=0xbbd91a08) at /build/php5-5.6.30+dfsg/Zend/zend_variables.h:35
#6  i_zval_ptr_dtor (zval_ptr=0xbbd91a08) at /build/php5-5.6.30+dfsg/Zend/zend_execute.h:79
#7  _zval_ptr_dtor (zval_ptr=zval_ptr@entry=0x7ffc4c55f698) at /build/php5-5.6.30+dfsg/Zend/zend_execute_API.c:424
#8  0x000000000060cdf6 in zif_array_reduce (ht=<optimized out>, return_value=<optimized out>, return_value_ptr=<optimized out>, this_ptr=<optimized out>, return_value_used=<optimized out>)
    at /build/php5-5.6.30+dfsg/ext/standard/array.c:4046
#9  0x00000000006e812a in dtrace_execute_internal (execute_data_ptr=<optimized out>, fci=<optimized out>, return_value_used=<optimized out>) at /build/php5-5.6.30+dfsg/Zend/zend_dtrace.c:97
#10 0x00000000007a8b10 in zend_do_fcall_common_helper_SPEC (execute_data=0x7f03a531e4e0) at /build/php5-5.6.30+dfsg/Zend/zend_vm_execute.h:560
#11 0x0000000000736e60 in execute_ex (execute_data=0x7f03a531e4e0) at /build/php5-5.6.30+dfsg/Zend/zend_vm_execute.h:363
#12 0x00000000006e7fc8 in dtrace_execute_ex (execute_data=0x7f03a531e4e0) at /build/php5-5.6.30+dfsg/Zend/zend_dtrace.c:73
#13 0x00000000007a9053 in zend_do_fcall_common_helper_SPEC (execute_data=0x7f03a531e338) at /build/php5-5.6.30+dfsg/Zend/zend_vm_execute.h:592
#14 0x0000000000736e60 in execute_ex (execute_data=0x7f03a531e338) at /build/php5-5.6.30+dfsg/Zend/zend_vm_execute.h:363
#15 0x00000000006e7fc8 in dtrace_execute_ex (execute_data=0x7f03a531e338) at /build/php5-5.6.30+dfsg/Zend/zend_dtrace.c:73
#16 0x00000000007a9053 in zend_do_fcall_common_helper_SPEC (execute_data=0x7f03a531db50) at /build/php5-5.6.30+dfsg/Zend/zend_vm_execute.h:592
#17 0x0000000000736e60 in execute_ex (execute_data=0x7f03a531db50) at /build/php5-5.6.30+dfsg/Zend/zend_vm_execute.h:363
#18 0x00000000006e7fc8 in dtrace_execute_ex (execute_data=0x7f03a531db50) at /build/php5-5.6.30+dfsg/Zend/zend_dtrace.c:73
#19 0x00000000007a9053 in zend_do_fcall_common_helper_SPEC (execute_data=0x7f03a531cc18) at /build/php5-5.6.30+dfsg/Zend/zend_vm_execute.h:592
#20 0x0000000000736e60 in execute_ex (execute_data=0x7f03a531cc18) at /build/php5-5.6.30+dfsg/Zend/zend_vm_execute.h:363
#21 0x00000000006e7fc8 in dtrace_execute_ex (execute_data=0x7f03a531cc18) at /build/php5-5.6.30+dfsg/Zend/zend_dtrace.c:73
#22 0x00000000007a7c8c in ZEND_INCLUDE_OR_EVAL_SPEC_TMP_HANDLER (execute_data=0x7f03a531c3c0) at /build/php5-5.6.30+dfsg/Zend/zend_vm_execute.h:8407
#23 0x0000000000736e60 in execute_ex (execute_data=0x7f03a531c3c0) at /build/php5-5.6.30+dfsg/Zend/zend_vm_execute.h:363
#24 0x00000000006e7fc8 in dtrace_execute_ex (execute_data=0x7f03a531c3c0) at /build/php5-5.6.30+dfsg/Zend/zend_dtrace.c:73
#25 0x00000000007a7658 in ZEND_INCLUDE_OR_EVAL_SPEC_VAR_HANDLER (execute_data=0x7f03a531c138) at /build/php5-5.6.30+dfsg/Zend/zend_vm_execute.h:13791
#26 0x0000000000736e60 in execute_ex (execute_data=0x7f03a531c138) at /build/php5-5.6.30+dfsg/Zend/zend_vm_execute.h:363
#27 0x00000000006e7fc8 in dtrace_execute_ex (execute_data=0x7f03a531c138) at /build/php5-5.6.30+dfsg/Zend/zend_dtrace.c:73
#28 0x00000000006fabb0 in zend_execute_scripts (type=1478981768, type@entry=8, retval=0x7f03582778b8, retval@entry=0x0, file_count=1501406296, file_count@entry=3)
    at /build/php5-5.6.30+dfsg/Zend/zend.c:1341
#29 0x0000000000695dd0 in php_execute_script (primary_file=0x7ffc4c5625b0) at /build/php5-5.6.30+dfsg/main/main.c:2613
#30 0x00000000007aaacb in do_cli (argc=1478981768, argv=0x7f03582778b8) at /build/php5-5.6.30+dfsg/sapi/cli/php_cli.c:998
#31 0x0000000000462c6d in main (argc=1478981768, argv=0x7f03582778b8) at /build/php5-5.6.30+dfsg/sapi/cli/php_cli.c:1382