On Monday 29 December 2008 21:37:52 Avi Kivity wrote: > Sheng Yang wrote: > > The free assigned device in the destroy path of VM, so as free irq. And > > we got cancel_work_sync() in free irq which can sync with the execution > > of scheduled work. And now before cancel_work_sync(), we disable the > > interrupt so that no more schedule work happen again. So after > > cancel_work_sync(), everything(I think it's irq handler and schedule work > > here) asynchronously should quiet down. > > > > Or I miss something? > > Suppose the work_struct gets scheduled, but is delayed somewhere in the > scheduler. Some kill -9s the VM, and it starts getting destroyed. > cancel_work_sync() can no longer truly cancel the work, so it has to > schedule and wait for its completion. > > So now we have kvm_assigned_dev_interrupt_work_handler() running in a > partially destroyed VM. It may work or not, but it's a fragile > situation (changing the order of destruction of components will likely > break things) and it's easy to avoid by keeping the reference count > elevated.
OK, got it. Thanks for explaining! -- regards Yang, Sheng -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
