On Mon, Sep 10, 2012 at 04:36:20PM +0200, Peter Zijlstra wrote:
> On Fri, 2012-09-07 at 11:39 -0700, Linus Torvalds wrote:
> > Al? Please look into this. I'm not entirely sure what's going on, but
> > lockdep complains about this:
> >
> > Possible interrupt unsafe locking scenario:
> >
> > CPU0 CPU1
> > ---- ----
> > lock(&(&p->alloc_lock)->rlock);
> > local_irq_disable();
> > lock(&(&new_timer->it_lock)->rlock);
> > lock(tasklist_lock);
> > <Interrupt>
> > lock(&(&new_timer->it_lock)->rlock);
> >
> > *** DEADLOCK ***
> >
> > and it looks real. IOW, if I read that right, we have the task_lock ->
> > it_lock dependency through exit_itimers(), and then we have the
> > tasklist_lock -> task_lock dependency everywhere else. So now it_lock
> > -> tasklist_lock becomes a deadlock.
>
> Agreed, I've got the following series from Oleg queued to solve this:
>
> http://marc.info/?l=linux-kernel&m=134600821828491&w=2
What's happening with this series ? I'm still seeing these traces in rc6.
Dave
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