mm/hugetlb: check for pte NULL pointer in __page_check_address()

commit 98398c3 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 <[email protected]> Cc: Naoya Horiguchi <[email protected]> Cc: Mel Gorman <[email protected]> Cc: qiuxishi <[email protected]> Cc: Hanjun Guo <[email protected]> Acked-by: Kirill A. Shutemov <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
ruppi · Jan 9, 2014 · 398bbc5 · 398bbc5
1 parent 31eb5f2
commit 398bbc5
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/mm/rmap.c b/mm/rmap.c
@@ -600,7 +600,11 @@ 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;
 	}