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Date: Tue, 31 Jul 2012 08:18:09 -0700
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>,
        Steven Rostedt <srostedt@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>,
        David Howells <dhowells@redhat.com>
Subject: Re: __update_max_tr: rcu_read_lock() used illegally while idle!
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On Tue, Jul 31, 2012 at 10:56:23AM -0400, Steven Rostedt wrote:
> On Tue, 2012-07-31 at 10:51 -0400, Steven Rostedt wrote:
> 
> > > OK, I will bite.  How about using something like RCU_NONIDLE(), either
> > > directly or open-coded, to make it a legal call site?
> > 
> > OK, then something like:
> > 
> > 	RCU_NONIDLE(max_data = task_uid(tsk));
> > 
> > would work when called normally or with idle?
> > 
> 
> The comment above RCU_NONIDLE() says:
> 
> 	This macro may be used from process-level code only.
> 
> Although I'm not sure what a 'level' is. Do you mean process-context? If
> so, then this will not work because it can be called from non process
> level code (return from interrupt), or any interrupt that enables
> interrupts.

Yep, process context.  It seems that I was naively expecting the
calls in interrupt context to be covered by rcu_irq_enter() and
rcu_irq_exit().  I take it that these calls are happening outside of
the rcu_irq_enter()-protected region?

							Thanx, Paul