Date: Wed, 23 Sep 2009 09:32:53 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Peter Zijlstra <peterz@infradead.org>,
       Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
       Chris Malley <mail@chrismalley.co.uk>, linux-kernel@vger.kernel.org,
       Steven Rostedt <rostedt@goodmis.org>
Subject: Re: perf sched record hangs machine
Message-ID: <20090923073253.GA18022@elte.hu>
References: <7863dc4c0909221409v7893bfd3o4b590d5951a233ba@mail.gmail.com> <20090922212453.GB6062@nowhere> <1253686585.7695.84.camel@twins>
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* Peter Zijlstra <peterz@infradead.org> wrote:

>         .size   default_send_IPI_self, .-default_send_IPI_self
> 
> Which seems to suggest that cmove is in __prepare_ICR, but I'm not 
> sure how that can cause a page-fault, as that function is rather 
> pointer-less.
> 
> Did it maybe delay evaluating apic->dest_logical that late, it appear 
> to be the first usage of that argument?
> 
> Ingo, any ideas?

Yeah, the problem is:

[    0.042445] Local APIC not detected. Using dummy APIC emulation.

we shouldnt be trying to program the lapic in that case - all ops should 
be a NOP, including send-ipi-self. Cyrill?

	Ingo
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