Symptoms

The CPU utilization reaches 100% and the following errors can be found in host server log:

"Error","Unknown","8060","ProcessPacketError","SourceCode.Hosting.Server.Services.TCPClientSocket.ProcessMessage","8060 ProcessPacket Error, Object reference not set to an instance of an object.","system","162.101.176.127","WPVWA00A0271:D:Program Files (x86)K2 blackpearlHost ServerBin","121195950","755eb0b4a6c9461a9160bc0c14d2b80d",""
 

Diagnoses

The issue was caused by some process instances trying to execute AD Service 2 SmartObject wrapper executed with blank filter field assigned in the input property.

 

Resolution 

Identify and stop offending process instances and then use Data Injector tool to modify the process with the correct values for the SmartObject call when the instance is in error.

The K2 Data Injector allows you to update Process Datafield and Xml Datafields in a process instance. This tool can be downloaded from K2 Underground:

http://old.k2underground.com/groups/k2_data_injector/default.aspx