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authorJianguo Wu <wujianguo@huawei.com>2013-12-18 17:08:59 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-01-08 09:42:12 -0800
commit2efb73fb4f0f5081ba6450e789b52f70247c80d9 (patch)
treee465ae3ab65422857f5bb82cd1076921f19c39df
parent1005954e40d50fbbbf48bd3c7fe4942f42f26f75 (diff)
downloadlinux-linaro-stable-2efb73fb4f0f5081ba6450e789b52f70247c80d9.tar.gz
mm/hugetlb: check for pte NULL pointer in __page_check_address()
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 <wujianguo@huawei.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Mel Gorman <mgorman@suse.de> Cc: qiuxishi <qiuxishi@huawei.com> Cc: Hanjun Guo <guohanjun@huawei.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--mm/rmap.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index bfca52c96999..f02c862fab69 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;
}