Re: Linux 3.6-rc4

From: Dave Jones
Date: Fri Sep 28 2012 - 15:12:53 EST


On Fri, Sep 21, 2012 at 05:16:39PM -0400, Dave Jones wrote:
> 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.

and still in rc7.

Peter ?

Dave
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