From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Mon, 11 May 2015 06:28:29 +0000 (+0530)
Subject: powerpc/mm: Return NULL for not present hugetlb page
X-Git-Tag: omap-for-v4.2/wakeirq-drivers-v2^2~2^2~82^2~2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7b868e81be38d5ad4f4aa4be819a5fa543cc5ee8;p=pandora-kernel.git

powerpc/mm: Return NULL for not present hugetlb page

We need to check whether pte is present in follow_huge_addr() and
properly return NULL if mapping is not present. Also use READ_ONCE
when dereferencing pte_t address.

Without this patch, we may wrongly return a zero pfn page in
follow_huge_addr().

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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