[snmp] Westhawk SNMP Stack version 5.1 stuck thread issue

[Birgit Arkesteijn]

Hi Alex,

The fix you mentioned was added to avoid a NullPointer exception. I do 
not think this change will solve your problem(s) of hanging threads.

See the discussion at 
http://snmp.westhawk.co.uk/pipermail/snmp/2007-January/000458.html
continued with
http://snmp.westhawk.co.uk/pipermail/snmp/2007-February/000460.html

Is there anything else in the StackTrace that suggests why notifyAll() 
in/on Transmitter.stand(Transmitter.java:144) is blocked or what it's 
waiting for?

Cheers, Birgit


On 23/07/08 12:25, Alex Ioannou wrote:
> Hi there
> 
> I'm experiencing some problems when running SNMP requests using the
> Westhawk SNMP stack, version 5.1.
> Threads on the application server are becoming stuck when attempting
> to clean up the SNMP context after
> sending an SNMP request to a device.
> 
> We are running our application on BEA Weblogic 10 application server.
>  We have an enterprise java bean
> that manages our SNMP requests to the westhawk API.   The application
> will send several SNMP requests
> simultaneously to different devices so several SNMP context objects
> will reside in memory and our application
> will have the possibility of invoking the destroy method simultaneously.
> 
> I looked through the source code for version 6 and found that a fix
> was made in Transmitter.java where
> one thread set the "me" variable to null in destroy() but a second
> would be about to call me.interrupt() in
> interruptMe(), resulting in a null pointer.
> 
> Will this fix help with my stuck thread issue or is there still a
> problem in the code?
> 
> 
> 	[deadlocked thread] ExecuteThread: '21' for queue: 'act-execute-queue':
> 	----------------------------------------------------------------------
> 	Thread 'ExecuteThread: '21' for queue: 'act-execute-queue'' is
> waiting to acquir
> 	e lock 'uk.co.westhawk.snmp.stack.Transmitter at 984dea' that is held by
> thread '73
> 	.106.72.80_161_null_v1_Trans0'
> 
> 	Stack trace:
> 	------------
> 		uk.co.westhawk.snmp.stack.Transmitter.stand(Transmitter.java:144)
> 		uk.co.westhawk.snmp.stack.Transmitter.destroy(Transmitter.java:161)
> 		uk.co.westhawk.snmp.stack.AbstractSnmpContext.freeTransmitters(AbstractS
> 	nmpContext.java:934)
> 		uk.co.westhawk.snmp.stack.AbstractSnmpContext.destroy(AbstractSnmpContex
> 	t.java:470)
> 	
> Thanks
> Alex
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-- 
-- Birgit Arkesteijn, birgit at westhawk.co.uk,
-- Westhawk Ltd, Albion Wharf, 19 Albion Street, Manchester M1 5LN, UK
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