Description:

While testing ZBX-27227 noticed that Zabbix FE hangs up for some time after system.run item test. System.run command's output is 15-16Mb

Precondition:

Agentd in passive mode on Linux machine.

Allow system.run[*] in agent config file.

Steps:

1. Create host with item key: system.run[head -c 16777210 /dev/zero | tr '\0' 'A']
2. Go to Item. Click Test
3. Click "Get value and test" button

Result:

Last value is shown in Latest data (as expected)

Zabbix is frozen and does not react on mouse click

Unresponsive screen page appears.

Expected:

Zabbix should not be frozen.

NOTE: 

• Could reproduce only on master 
• This does not happen, when I press "Get value" button in Test form