BlockedIndefinitelyOnMVar exception

[Neil Mitchell]

Hi,

I have a very big and highly threaded program that generates a
BlockedIndefinitelyOnMVar exception when run. I have spent a
reasonable amount of time pouring over the source code, as has Max
Bolingbroke. Neither of us have the slightest idea why it raises the
exception.

Some questions:

* Does anyone know the exact sequence of actions that causes this
exception to be thrown? I couldn't find it written down.
* How confident are people that this exception does really mean that
it is in a blocked state? Is there any chance the error could be
raised incorrectly?
* Any debugging tips for this problem?

Thanks, Neil