3.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dexuan Cui <de...@microsoft.com>

commit d1cd1210834649ce1ca6bafe5ac25d2f40331343 upstream.

pte_pfn() returns a PFN of long (32 bits in 32-PAE), so "long <<
PAGE_SHIFT" will overflow for PFNs above 4GB.

Due to this issue, some Linux 32-PAE distros, running as guests on Hyper-V,
with 5GB memory assigned, can't load the netvsc driver successfully and
hence the synthetic network device can't work (we can use the kernel parameter
mem=3000M to work around the issue).

Cast pte_pfn() to phys_addr_t before shifting.

Fixes: "commit d76565344512: x86, mm: Create slow_virt_to_phys()"
Signed-off-by: Dexuan Cui <de...@microsoft.com>
Cc: K. Y. Srinivasan <k...@microsoft.com>
Cc: Haiyang Zhang <haiya...@microsoft.com>
Cc: gre...@linuxfoundation.org
Cc: linux...@kvack.org
Cc: o...@aepfle.de
Cc: a...@canonical.com
Cc: jasow...@redhat.com
Cc: dave.han...@intel.com
Cc: r...@redhat.com
Cc: sta...@vger.kernel.org
Link: 
http://lkml.kernel.org/r/1414580017-27444-1-git-send-email-de...@microsoft.com
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 arch/x86/mm/pageattr.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -405,7 +405,7 @@ phys_addr_t slow_virt_to_phys(void *__vi
        psize = page_level_size(level);
        pmask = page_level_mask(level);
        offset = virt_addr & ~pmask;
-       phys_addr = pte_pfn(*pte) << PAGE_SHIFT;
+       phys_addr = (phys_addr_t)pte_pfn(*pte) << PAGE_SHIFT;
        return (phys_addr | offset);
 }
 EXPORT_SYMBOL_GPL(slow_virt_to_phys);


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