[AGENT++] Core dump related to rows being removed from agentX tables?

[john.edmonds at bt.com]

Hi,
 
I have a setup that works most of the time, but occasionally core dumps (under linux on PPC).  I suspect that it is somehow related to removing rows from tables (or multiple rows), when I don't remove table rows I never seem to get core dumps.  I am running an AgentX++ sub agent with Net-SNMP 5.4.1 master agent.
 
agent++ v3.5.27.b
agentX++ v1.4.15
snmp++ v3.2.21.a
 
This a stack backtrace I got from one core dump, the crash occurs at #0, List.h line 1154. Looks like a "get_next"...
 
#7 thread_starter () at threads.cpp:486
#6 Agentpp::TaskManager::run () at threads.cpp:742
#5 Agentpp::MibTask::run () at threads.cpp:920
#4 Agentpp::SubAgentXMib::do_process_request () at agentx_subagent.cpp:926
#3 Agentpp::Mib::process_request () at mib.cpp:3297
#2 Agentpp::SubAgentXMib::find_next () at agentx_subagent.cpp:1072
#1 Agentpp::MibTable::find_succ () at mib.cpp:1753
#0 Agentpp::MibTable::find_next () at List.h:1154
 
I have a MIB Browser that is constantly refreshing the display of the Tables.  Could there be a missing mutex somewhere between table row updates and browser SNMP gets perhaps?  Or confusion between a get on one table and row removal on another?
 
Any suggestions as to what might be happening or what I could do to patch code to stop core dumps?  Add some bounds checking?
 
Best regards,
John Edmonds (BT)