On Tue, Aug 20, 2013 at 02:34:14PM +0200, Rafael J. Wysocki wrote: > On Tuesday, August 20, 2013 08:22:00 AM Tejun Heo wrote: > > On Tue, Aug 20, 2013 at 02:30:18PM +0200, Rafael J. Wysocki wrote: > > > > So, I don't think we can simply turn TASK_UNITERRUPTIBLE to > > > > TASK_KILLABLE at this point. We really need to strictly define where > > > > a task can freeze before being able to do anything like this. > > > > > > But we could do that for user space tasks I suppose? > > > > Even for userland tasks, we don't know where the task is stuck at. I > > think there are enough freeze points in the kernel which are in the > > middle of something which can be used by userland tasks excuting some > > syscall. We need to collect all those sites into well defined trap > > points before doing this. > > OK, thanks!
I scanned through try_to_freeze() users and it seems like we don't have that many which can be hit by userland tasks. I think it should be doable to audit all the users, remove the ones which can be invoked by userland and make try_to_freeze() whine loudly if it's running off a userland task except from well-defined spots. Anyways, we need to ensure that userland task doesn't get stuck deep in the kernel before allowing this. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
