After commit 58b6e5e8f1ad ("hugetlbfs: fix memory leak for resv_map"),
i_mapping->private_data will be NULL for mode that is not regular and link.
Then, it might cause NULL pointer derefernce in hugetlb_reserve_pages()
when do_mmap. We can avoid protential null pointer dereference by
judging whether it have been allocated.
Fixes: 58b6e5e8f1ad ("hugetlbfs: fix memory leak for resv_map")
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Yufen Yu <yuyufen@xxxxxxxxxx>
---
mm/hugetlb.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 97b1e0290c66..15e4baf2aa7d 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4465,6 +4465,8 @@ int hugetlb_reserve_pages(struct inode *inode,
*/
if (!vma || vma->vm_flags & VM_MAYSHARE) {
resv_map = inode_resv_map(inode);
+ if (!resv_map)
+ return -EOPNOTSUPP;
chg = region_chg(resv_map, from, to);
--
2.16.2.dirty
