On Wed, 6 Apr 2005, Rafael J. Wysocki wrote: > > What happens if a process owns a lock needed to suspend a device and it is > > waiting in TASK_UNINTERRUPTIBLE? > > Well, we're in trouble. :-) > > However, if any process that we have frozen owns such a lock, we're in trouble > too. Thus it won't help if we forcibly freeze the uninterruptible process. > Worse yet, there won't be any way to wake it up afterwards. OTOH, if we leave > it in TASK_UNINTERRUPTIBLE, it may (potentially) be woken up by an interrupt > handler (as you pointed out previously :-)) and release the lock. > > Frankly, I can't see any probable scenario leading to this kind of trouble. > Seemingly, it would require someone to take a lock and (knowingly) do > something that could end up in uninterruptible sleep, which IMHO is not > a good idea. It happens all the time in the USB core, when dealing with a newly-connected device. Alan Stern
