From: David Miller <davem@davemloft.net>
Date: Wed, 2 Oct 2013 18:25:09 +0000 (-0400)
Subject: mm: Fix generic hugetlb pte check return type.
X-Git-Tag: v3.12-rc4~26^2~2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=26794942461f438a6bc725ec7294b08a6bd782c4;p=pandora-kernel.git

mm: Fix generic hugetlb pte check return type.

The include/asm-generic/hugetlb.h stubs that just vector huge_pte_*()
calls to the pte_*() implementations won't work in certain situations.

x86 and sparc, for example, return "unsigned long" from the bit
checks, and just go "return pte_val(pte) & PTE_BIT_FOO;"

But since huge_pte_*() returns 'int', if any high bits on 64-bit are
relevant, they get chopped off.

The net effect is that we can loop forever trying to COW a huge page,
because the huge_pte_write() check signals false all the time.

Reported-by: Gurudas Pai <gurudas.pai@oracle.com>
Tested-by: Gurudas Pai <gurudas.pai@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: David Rientjes <rientjes@google.com>
---

Reading git-diff-tree failed