Note I am not going to advocate for try ... catch .. finally, because I think that language mechanism is abused out the wazoo for handling all kinds of things,

Note I am not going to advocate for try ... catch .. finally, because I think that language mechanism is abused out the wazoo for handling all kinds of things, like IO errors, but this is exactly what try ... finally would be for. Regardless, I think just killing the task instantly, even with partial updates to memory, would be totally fine. It'd be cheap, as automatically undoing the updates (effectively a transaction rollback) is still too expensive. Software transactional memory just comes with too much overhead. I vote "kill and unwind" and then dealing with partial updates has to be left to a higher level.