Re: [BUG] perf: bogus correlation of kernel symbols

From: Dave Jones
Date: Thu May 12 2011 - 14:38:11 EST


On Thu, May 12, 2011 at 02:06:30PM -0400, David Miller wrote:
> From: Stephane Eranian <eranian@xxxxxxxxxx>
> Date: Thu, 12 May 2011 16:48:46 +0200
>
> > I think there is a serious problem with kernel symbol correlation
> > with the latest perf in 2.6.39-rc7-tip.
>
> The behavior seems to be intentional, so that we don't expose internal
> kernel addresses to userspace.

Sounds like commit 9f36e2c448007b54851e7e4fa48da97d1477a175

> I hate this too, and I think it's absolutely rediculous.
>
> Also, like you, I lost an entire afternoon trying to figure out why
> this started happening.
>
> I wish we could revert this change.

At least it can be permanently disabled..

echo kernel.kptr_restrict = 0 >> /etc/sysctl.conf

Dave

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