Break COW PTE before collecting the pages in COW-ed PTE.

Signed-off-by: Chih-En Lin <shiyn.lin@gmail.com>
---
 mm/migrate_device.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index 721b2365dbca..2930e591e8fc 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -106,6 +106,8 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 		}
 	}
 
+	if (break_cow_pte_range(vma, start, end))
+		return migrate_vma_collect_skip(start, end, walk);
 	if (unlikely(pmd_bad(*pmdp)))
 		return migrate_vma_collect_skip(start, end, walk);
 
-- 
2.34.1