On Wed, Jun 15, 2016 at 12:30:07PM -0400, Steven Rostedt wrote:
> > +++ b/kernel/locking/rtmutex.c
> > @@ -488,7 +488,7 @@ static int rt_mutex_adjust_prio_chain(st
> > * enabled we continue, but stop the requeueing in the chain
> > * walk.
> > */
> > - if (waiter->prio == task->prio) {
> > + if (waiter->prio == task->prio && !dl_task(task)) {
>
> Isn't task the owner of the lock?
No, task is blocked on something.
> What happens if the waiter is a
> deadline task?
So the test here is a shortcut to terminate the Pi chain adjust, it says
that if the waiter and task have the same priority, we're done. Further
adjustments will not make a difference.
The problem is that for deadline tasks, prio is a useless number, so
even if they match (all deadline tasks have prio -1) they might still
not actually match.
After the last patch I suppose we could do something like:
waiter->prio == task->prio && waiter->deadline == task->dl.deadline
In any case, any condition that compares just two 'prio' values is per
definition broken if DL tasks are involved.
