This patch can avoid protential null pointer dereference for resv_map.
As Mike Kravetz say:
Even if we can not hit this condition today, I still believe it
would be a good idea to make this type of change. It would
prevent a possible NULL dereference in case the structure of code
changes in the future.
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Suggested-by: Mike Kravetz <mike.kravetz@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..fe74f94e5327 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 -EACCES;
chg = region_chg(resv_map, from, to);
--
2.16.2.dirty
