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Subject: Re: Minor PKRU bug?
To: Andy Lutomirski <luto@amacapital.net>, X86 ML <x86@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
References: <CALCETrVUZAo2=ZK8EZxjHDGiUj=XU_d-=L9SSDYU+F75CZiLsA@mail.gmail.com>
From: Dave Hansen <dave.hansen@linux.intel.com>
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Date: Tue, 12 Jul 2016 08:32:26 -0700
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On 07/09/2016 02:27 PM, Andy Lutomirski wrote:
> is_prefetch in arch/x86/mm/fault.c can be called on a user address
> that's not readable due to PKRU.  This could break it.  You might need
> to add a get_user_exec or similar.

Thanks for the heads-up.  I think I'll just need a version that does
something along the lines of stac/clac, but with PKRU.

I think I can do it with an "_exec" variant of probe_kernel_address(),
but it's a bit messy.