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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	hpa@zytor.com, eranian@google.com, linux-kernel@vger.kernel.org,
	fweisbec@gmail.com, akpm@linux-foundation.org,
	tglx@linutronix.de, linux-tip-commits@vger.kernel.org,
	Robert Richter <robert.richter@amd.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Jeremy Fitzhardinge <jeremy@goop.org>
Subject: Re: [tip:perf/core] perf/x86: Fix USER/KERNEL tagging of samples
Date: Tue, 10 Jul 2012 10:52:40 +0200
Message-ID: <1341910360.3462.99.camel@twins> (raw)
In-Reply-To: <20120710082104.GA11187@gmail.com>

On Tue, 2012-07-10 at 10:21 +0200, Ingo Molnar wrote:
> Another boundary condition would be when we intentionally 
> twiddle the GDT: such as during suspend or during BIOS upcalls. 
> Can we then get a PMU interrupt? If yes then this will probably 
> result in garbage:
> 
> > > > +             desc = __this_cpu_ptr(&gdt_page.gdt[0]);
> 
> it won't outright crash, we don't ever deallocate our GDT - but 
> it will return a garbage RIP.

Nothing we can do about that though..

> Then there's also all the Xen craziness with segments ...

I don't think Xen Dom0 has PMU access, that would be their Hyper-visor
thingy's job, no?

Anyway, that seems a problem for Jeremy and Konrad..

  reply index

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-06  6:20 tip-bot for Peter Zijlstra
2012-07-06 16:29 ` Linus Torvalds
2012-07-06 18:12   ` Peter Zijlstra
2012-07-06 18:16     ` Linus Torvalds
2012-07-06 18:34       ` Linus Torvalds
2012-07-06 20:48         ` Peter Zijlstra
2012-07-06 20:59           ` Linus Torvalds
2012-07-09 11:23         ` Peter Zijlstra
2012-07-09 17:55           ` Linus Torvalds
2012-07-10  9:02             ` Peter Zijlstra
2012-07-10  9:48               ` Ingo Molnar
2012-07-10  9:50               ` Peter Zijlstra
2012-07-10  9:52                 ` Peter Zijlstra
2012-07-10  9:55                 ` Ingo Molnar
2012-07-31 17:57               ` [tip:perf/urgent] perf/x86: Fix USER/ KERNEL tagging of samples properly tip-bot for Peter Zijlstra
2012-07-09 18:41           ` [tip:perf/core] perf/x86: Fix USER/KERNEL tagging of samples Ingo Molnar
2012-07-10  7:54             ` Peter Zijlstra
2012-07-10  8:02               ` Ingo Molnar
2012-07-10  8:21               ` Ingo Molnar
2012-07-10  8:52                 ` Peter Zijlstra [this message]
2012-07-10  9:48                   ` Ingo Molnar
2012-07-31 18:11                     ` H. Peter Anvin

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