[PATCH 3/5] mm/migrate.c: fix potential indeterminate pte entry in migrate_vma_insert_page()

Miaohe Lin
2021-03-20T09:38:04Z

If the zone device page does not belong to un-addressable device memory,
the variable entry will be uninitialized and lead to indeterminate pte
entry ultimately. Fix this unexpectant case and warn about it.

Fixes: df6ad69838fc ("mm/device-public-memory: device memory cache coherent with CPU")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
mm/migrate.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/mm/migrate.c b/mm/migrate.c
index 20a3bf75270a..271081b014cb 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2972,6 +2972,13 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,

swp_entry = make_device_private_entry(page, vma->vm_flags & VM_WRITE);
entry = swp_entry_to_pte(swp_entry);
+ } else {
+ /*
+ * For now we only support migrating to un-addressable
+ * device memory.
+ */
+ WARN_ON(1);
+ goto abort;
}
} else {
entry = mk_pte(page, vma->vm_page_prot);
--
2.19.1