Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit a9af0c5d authored by Naoya Horiguchi's avatar Naoya Horiguchi Committed by Linus Torvalds
Browse files

mm/hugetlb.c: add NULL check of return value of huge_pte_offset 



huge_pte_offset() could return NULL, so we need NULL check to avoid
potential NULL pointer dereferences.

Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 87c1b497

mm/hugetlb.c

+3 −2
Original line number Diff line number Diff line
@@ -2690,7 +2690,8 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, 
				BUG_ON(huge_pte_none(pte));

				spin_lock(ptl);

				ptep = huge_pte_offset(mm, address & huge_page_mask(h));

				if (likely(pte_same(huge_ptep_get(ptep), pte)))

				if (likely(ptep &&

					   pte_same(huge_ptep_get(ptep), pte)))

					goto retry_avoidcopy;

				/*

				 * race occurs while re-acquiring page table
@@ -2734,7 +2735,7 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, 
	 */

	spin_lock(ptl);

	ptep = huge_pte_offset(mm, address & huge_page_mask(h));

	if (likely(pte_same(huge_ptep_get(ptep), pte))) {

	if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {

		ClearPagePrivate(new_page);



		/* Break COW */