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

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

From: Jianguo Wu <redacted>

commit 98398c32f6687ee1e1f3ae084effb4b75adb0747 upstream.

In __page_check_address(), if address's pud is not present,
huge_pte_offset() will return NULL, we should check the return value.

Signed-off-by: Jianguo Wu <redacted>
Cc: Naoya Horiguchi <redacted>
Cc: Mel Gorman <mgorman@suse.de>
Cc: qiuxishi <redacted>
Cc: Hanjun Guo <guohanjun@huawei.com>
Acked-by: Kirill A. Shutemov <redacted>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ luis: backported to 3.5: adjusted context ]
Signed-off-by: Luis Henriques <redacted>
---
 mm/rmap.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/rmap.c b/mm/rmap.c
index aa95e59..2b03b31 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c

@@ -623,7 +623,11 @@ pte_t *__page_check_address(struct page *page, struct mm_struct *mm,
 	spinlock_t *ptl;
 
 	if (unlikely(PageHuge(page))) {
+		/* when pud is not present, pte will be NULL */
 		pte = huge_pte_offset(mm, address);
+		if (!pte)
+			return NULL;
+
 		ptl = &mm->page_table_lock;
 		goto check;
 	}

-- 
1.8.3.2