RFR(XXS): 8007147: Trace event ExecuteVMOperation may get dangling pointer

David Holmes david.holmes at oracle.com
Tue Feb 19 18:38:29 PST 2013

On 20/02/2013 5:30 AM, Dean Long wrote:
> On 2/19/2013 11:00 AM, Staffan Larsen wrote:
>> On 19 feb 2013, at 19:56, Dean Long <dean.long at oracle.com
>> <mailto:dean.long at oracle.com>> wrote:
>>> When the VM_Operation is created, we could take a snapshot of the
>>> thread_id of the caller, then use that later.
>> One problem with that is if the thread_id gets reused for a new thread
>> quickly after the old thread terminates. This is perhps ulikely, but
>> could happen.
>>> Or we could block the creating thread from fully exiting until the VM
>>> op executes.
>> That would introduce a lot more synchronization and state to keep
>> track of.
> I think we could do it with a reference count on the thread, a wait in
> thread exit, and a notify in the VM thread.
> We have a similar dangling pointer problem with JVMTI (7154963), and a
> reference count should solve that problem as well.

I think that proposal needs a lot more investigation, certainly it is 
well out of scope for this bug. There are potential dangling thread 
pointers all over the JVM interfaces.


> dl
>> /Staffan

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