create_old2new_and_copy_of function tries to allocate +100GB in RAM and finally crashes. Code does not change on 4.2.1.

We have 3 servers and only 1 have this problem (the most critical of course else there is no fun !)

Biggest log file is 2.2GB long other logs are mere few kB.

Steps to reproduce:

1. Start the agent with log collection turned on
2. Wait 20 minutes

Result:

A child process crash, the main process exits with code 0

Log:

   886:20190523:162821.565 Starting Zabbix Agent [XXXXX]. Zabbix 4.0.7 (revision 92831).
   886:20190523:162821.570 **** Enabled features ****
   886:20190523:162821.570 IPv6 support:          YES
   886:20190523:162821.570 TLS support:           YES
   886:20190523:162821.570 **************************
   886:20190523:162821.570 using configuration file: /etc/zabbix/zabbix_agentd.conf
   886:20190523:162821.573 agent #0 started [main process]
   890:20190523:162821.575 agent #1 started [collector]
   891:20190523:162821.577 agent #2 started listener #1
   893:20190523:162821.582 agent #4 started listener #3
   894:20190523:162821.583 agent #5 started active checks #1
   892:20190523:162821.589 agent #3 started listener #2
   894:20190523:165017.515 file:logfiles.c,line:1163 zbx_malloc: out of memory. Requested 102359681469 bytes.
   886:20190523:165017.544 One child process died (PID:894,exitcode/signal:1). Exiting ...
zabbix_agentd [886]: Error waiting for process with PID 894: [10] No child processes
   886:20190523:165017.562 Zabbix Agent stopped. Zabbix 4.0.7 (revision 92831).

Expected:
No crash or at least service restarted