1 files changed, 10 insertions, 0 deletions
diff --git a/mm/gup.c b/mm/gup.c
index 7e7f0054d628..4ae1a9b6a968 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1065,6 +1065,16 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
 				i = follow_hugetlb_page(mm, vma, pages, vmas,
 						&start, &nr_pages, i,
 						gup_flags, locked);
+				if (locked && *locked == 0) {
+					/*
+					 * We've got a VM_FAULT_RETRY
+					 * and we've lost mmap_sem.
+					 * We must stop here.
+					 */
+					BUG_ON(gup_flags & FOLL_NOWAIT);
+					BUG_ON(ret != 0);
+					goto out;
+				}
 				continue;
 			}
 		}