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Date: Fri, 8 Aug 2014 14:43:47 -0700
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Amit Shah <amit.shah@redhat.com>
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Subject: Re: [PATCH tip/core/rcu 1/2] rcu: Parallelize and economize NOCB
 kthread wakeups
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On Sat, Aug 09, 2014 at 12:04:24AM +0530, Amit Shah wrote:
> On (Fri) 08 Aug 2014 [11:18:35], Paul E. McKenney wrote:

[ . . . ]

> > Hmmm... What happens if you boot a7d7a143d0b4cb1914705884ca5c25e322dba693
> > with the kernel parameter "acpi=off"?
> 
> That doesn't change anything - still hangs.
> 
> I intend to look at this more on Monday, though - turning in for
> today.  In the meantime, if there's anything else you'd like me to
> try, please let me know.

OK, given that I still cannot reproduce it, I do need your help with
the diagnostics.  And so what sorts of diagnostics work for you in
the hung state?  Are you able to dump ftrace buffers?

If you are able to dump ftrace buffers, please enable rcu:rcu_nocb_wake
and send me the resulting trace.

							Thanx, Paul