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Date: Fri, 3 May 2013 07:34:11 -0700
From: Andi Kleen <ak@linux.intel.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: mingo@kernel.org, linux-kernel@vger.kernel.org, eranian@google.com
Subject: Re: [PATCH 2/3] perf, x86, lbr: Fix LBR filter
Message-ID: <20130503143411.GO19487@tassilo.jf.intel.com>
References: <20130503121122.931661809@chello.nl>
 <20130503121256.158211806@chello.nl>
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> +	} else {
> +		/*
> +		 * The LBR logs any address in the IP, even if the IP just
> +		 * faulted. This means userspace can control the from address.
> +		 * Ensure we don't blindy read any address by validating it is
> +		 * a known text address.
> +		 */
> +		if (kernel_text_address(from))

Sorry doing it this way is just incredible expensive and dumb.

After all the tool is called "perf" and not "non perf"

-Andi