Description:
------------
PHP crashes randomly during running WordPress crontask:

reason:         lsphp-7.1 killed by SIGSEGV
cmdline:        lsphp5: ..skipped.. ./wp-cron.php

PHP 7.1.18 (cli) (built: May 31 2018 17:47:26) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.1.0, Copyright (c) 1998-2018 Zend Technologies
    with the ionCube PHP Loader (enabled) + Intrusion Protection from ioncube24.com (unconfigured) v10.2.1, Copyright (c) 2002-2018, by ionCube Ltd.
    with Zend OPcache v7.1.18, Copyright (c) 1999-2018, by Zend Technologies


Test script:
---------------
It's a regular WordPress wp-cron.php file.


Expected result:
----------------
Crontask complete without crash.

Actual result:
--------------
Program terminated with signal 11, Segmentation fault.
#0  0x00007fa300df3c60 in ?? ()
(gdb) bt
#0  0x00007fa300df3c60 in ?? ()
#1  0x00007ffd9c11a310 in ?? ()
#2  0x000000000076ce58 in process_nested_data (rval=<optimized out>, objprops=0, elements=140727221855168, ht=0x7ffd9c11a420, var_hash=0x7fa2d61fffff,
    max=0x7fa300e1d000 "", p=0x7fa2d6dc85a6) at /usr/local/directadmin/custombuild/php-7.1.18/ext/standard/var_unserializer.c:376
#3  php_var_unserialize_internal (rval=<optimized out>, p=0x7fa2d6dc85a6, max=0x7fa300e1d000 "", var_hash=0x7fa2d61fffff)
    at /usr/local/directadmin/custombuild/php-7.1.18/ext/standard/var_unserializer.c:1330
#4  0x00002000f7a755ac in ?? ()
#5  0x0000010e00000022 in ?? ()
#6  0x00007fa2d6dc8498 in ?? ()
#7  0x0000000003437300 in ?? ()
#8  0x00000000032064d0 in ?? ()
#9  0x0000000003091520 in ?? ()
#10 0x00007fa2d6dc84ba in ?? ()
#11 0x00007fa2d6dc8498 in ?? ()
#12 0x00007fa2d6dc85a6 in ?? ()
#13 0x00007ffd9c11a6c0 in ?? ()
#14 0x00000000008acd8f in zend_verify_arg_type (cache_slot=<optimized out>, default_value=0x0, arg=<optimized out>, arg_num=16, zf=0x7fa200000000)
    at /usr/local/directadmin/custombuild/php-7.1.18/Zend/zend_execute.c:958
#15 ZEND_RECV_SPEC_HANDLER () at /usr/local/directadmin/custombuild/php-7.1.18/Zend/zend_vm_execute.h:1470
#16 0x00007ffd9c11a6c0 in ?? ()
#17 0x0000000000000004 in ?? ()
#18 0x00002000f7a1a350 in ?? ()
#19 0x0000010e00000022 in ?? ()
#20 0x00007fa2d6dc8498 in ?? ()
#21 0x000000000323d7c0 in ?? ()
#22 0x00000000032064d0 in ?? ()
#23 0x00007fa2f7a1a190 in ?? ()
#24 0x000000000074bee8 in php_strspn (s1=0x7ffd9c11a3c0 " \025\t\003", s2=0x7fa300e15008 "\034Q\247\367\242\177", s1_end=0x10 <Address 0x10 out of bounds>,
    s2_end=0xffffffffff46fbf7 <Address 0xffffffffff46fbf7 out of bounds>) at /usr/local/directadmin/custombuild/php-7.1.18/ext/standard/string.c:1757
#25 0x00007fa2f7a1a190 in ?? ()
#26 0x00007fa2d7f5dd20 in ?? ()
#27 0x00007ffd9c11a660 in ?? ()
#28 0x000000000085af5b in ZEND_ADD_ARRAY_ELEMENT_SPEC_TMP_CONST_HANDLER () at /usr/local/directadmin/custombuild/php-7.1.18/Zend/zend_vm_execute.h:13752
#29 0x00007fa2d6d9bbc0 in ?? ()
#30 0x00007fa2d6d9bba0 in ?? ()
#31 0x000000000082630e in _zend_hash_del_el_ex (prev=0x2000, p=0x1377, idx=14766088, ht=0x7ffd9c11a400)
    at /usr/local/directadmin/custombuild/php-7.1.18/Zend/zend_hash.c:969
#32 zend_hash_str_del_ind (ht=0x7ffd9c11a400, str=0x7fa2000f4240 <Address 0x7fa2000f4240 out of bounds>, len=140338040721974)
    at /usr/local/directadmin/custombuild/php-7.1.18/Zend/zend_hash.c:1144
#33 0x00007fa2f783edf3 in ?? ()
#34 0x000000019c11a870 in ?? ()
#35 0x0000000000000000 in ?? ()
(gdb)
(gdb)
(gdb) frame 2
#2  0x000000000076ce58 in process_nested_data (rval=<optimized out>, objprops=0, elements=140727221855168, ht=0x7ffd9c11a420, var_hash=0x7fa2d61fffff,
    max=0x7fa300e1d000 "", p=0x7fa2d6dc85a6) at /usr/local/directadmin/custombuild/php-7.1.18/ext/standard/var_unserializer.c:376
376             while (elements-- > 0) {
(gdb)
(gdb) frame 3
#3  php_var_unserialize_internal (rval=<optimized out>, p=0x7fa2d6dc85a6, max=0x7fa300e1d000 "", var_hash=0x7fa2d61fffff)
    at /usr/local/directadmin/custombuild/php-7.1.18/ext/standard/var_unserializer.c:1330
1330            if (!process_nested_data(UNSERIALIZE_PASSTHRU, Z_ARRVAL_P(rval), elements, 0)) {
(gdb)
(gdb) frame 14
#14 0x00000000008acd8f in zend_verify_arg_type (cache_slot=<optimized out>, default_value=0x0, arg=<optimized out>, arg_num=16, zf=0x7fa200000000)
    at /usr/local/directadmin/custombuild/php-7.1.18/Zend/zend_execute.c:958
958             if (UNEXPECTED(!zend_check_type(zf, cur_arg_info, arg, &ce, cache_slot, default_value, 0))) {
(gdb)
(gdb) frame 24
#24 0x000000000074bee8 in php_strspn (s1=0x7ffd9c11a3c0 " \025\t\003", s2=0x7fa300e15008 "\034Q\247\367\242\177", s1_end=0x10 <Address 0x10 out of bounds>,
    s2_end=0xffffffffff46fbf7 <Address 0xffffffffff46fbf7 out of bounds>) at /usr/local/directadmin/custombuild/php-7.1.18/ext/standard/string.c:1757
1757            for (spanp = s2; p != s1_end && spanp != s2_end;) {
(gdb) frame 28
#28 0x000000000085af5b in ZEND_ADD_ARRAY_ELEMENT_SPEC_TMP_CONST_HANDLER () at /usr/local/directadmin/custombuild/php-7.1.18/Zend/zend_vm_execute.h:13752
13752                   } else if (Z_TYPE_P(offset) == IS_TRUE) {
(gdb)
(gdb) frame 30
#30 0x00007fa2d6d9bba0 in ?? ()
(gdb)
(gdb) frame 31
#31 0x000000000082630e in _zend_hash_del_el_ex (prev=0x2000, p=0x1377, idx=14766088, ht=0x7ffd9c11a400)
    at /usr/local/directadmin/custombuild/php-7.1.18/Zend/zend_hash.c:969
969                     } while (ht->nNumUsed > 0 && (UNEXPECTED(Z_TYPE(ht->arData[ht->nNumUsed-1].val) == IS_UNDEF)));
(gdb)
(gdb) frame 32
#32 zend_hash_str_del_ind (ht=0x7ffd9c11a400, str=0x7fa2000f4240 <Address 0x7fa2000f4240 out of bounds>, len=140338040721974)
    at /usr/local/directadmin/custombuild/php-7.1.18/Zend/zend_hash.c:1144
1144                                    _zend_hash_del_el_ex(ht, idx, p, prev);
(gdb) q