mx6: suspicious RCU usage

[paulmck@linux.vnet.ibm.com (Paul E. McKenney)]

On Tue, Jul 14, 2015 at 01:59:10PM -0300, Fabio Estevam wrote:
> On Tue, Jul 14, 2015 at 1:44 PM, Fabio Estevam <festevam@gmail.com> wrote:
> 
> > With your patch applied I am running several suspend/resume cycles and
> > I am seeing different problems now from time to time (like 1 out 10
> > times). The kernel dump does not look like the same every time, but
> > here is one example:
> 
> Here is another one I just got, and it seems to be more informative:
> 
> http://pastebin.com/T4YxuLCg

This might simply be a symptom of the earlier "Unable to handle
kernel paging request at virtual address 708ebbfa".  However, the
usual cause of the later "rcu_read_lock() used illegally while idle!"
is just that.  In this case, might the interrupt have occurred
without irq_enter() being invoked?

(But there are probably two interleaved stack traces, and I am not
certain that I am getting them untangled properly.)

							Thanx, Paul