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Date: Fri, 27 Mar 2009 10:28:43 -0400 (EDT)
From: Steven Rostedt <rostedt@goodmis.org>
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To: Frederic Weisbecker <fweisbec@gmail.com>
cc: Maneesh Soni <maneesh@in.ibm.com>, LKML <linux-kernel@vger.kernel.org>,
       Ingo Molnar <mingo@elte.hu>, Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH][GIT PULL] tracing/wakeup: move access to wakeup_cpu into
 spinlock
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On Fri, 27 Mar 2009, Frederic Weisbecker wrote:
> > 
> > Hmm, looking back at the call stack:
> > 
> > > >  [<ffffffff806f8264>] schedule+0xd99/0x10f9
> > > >  [<ffffffff806fb61b>] ? trace_hardirqs_on_thunk+0x3a/0x3c
> > > >  [<ffffffff8027d2cb>] ? delayed_work_timer_fn+0x0/0x38
> > > >  [<ffffffff8020d56d>] retint_careful+0x12/0x2e
> > 
> > I wonder if we do not set up a stack frame properly. retint_careful is 
> > called by assembly. I'll have a look at that
> 
> 
> Aah, indeed.
> May be should probe_kernel_address before saving
> the addresses.
> 

Looking at the retint_careful, I'm 90% sure that is the bug.

Unfortunately, the CALLER_ADDR2 is a built in gcc function.

Looks like only the wakeup latency tracer calls it, perhaps we should 
simply pass 0 instead?

-- Steve

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