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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: benh@kernel.crashing.org, scottwood@freescale.com
Subject: Re: [PATCH] powerpc: Fix bad pmd error with book3E config
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Date: Tue, 18 Jun 2013 18:32:22 +0530
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"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> writes:

> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
>
> Book3E uses the hugepd at PMD level and don't encode pte directly
> at the pmd level. So it will find the lower bits of pmd set
> and the pmd_bad check throws error. Infact the current code
> will never take the free_hugepd_range call at all because it will
> clear the pmd if it find a hugepd pointer.
>
> Reported-by: Scott Wood <scottwood@freescale.com>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Ben,

This is regression introduced by
e2b3d202d1dba8f3546ed28224ce485bc50010be 
"powerpc: Switch 16GB and 16MB explicit hugepages to a different page table format"

and should go upstream in 3.10

$git describe  --contains e2b3d202d1dba8f3546ed28224ce485bc50010be
v3.10-rc1~121^2~15

Without this path, we leak hugepd with all subarchs using old huge page
directory format.

-aneesh