From: Miaohe Lin <linmiaohe@xxxxxxxxxx> Subject: mm/migrate.c: fix potential indeterminate pte entry in migrate_vma_insert_page() 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 unexpected case and warn about it. Link: https://lkml.kernel.org/r/20210325131524.48181-4-linmiaohe@xxxxxxxxxx Fixes: df6ad69838fc ("mm/device-public-memory: device memory cache coherent with CPU") Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> Cc: Alistair Popple <apopple@xxxxxxxxxx> Cc: Jerome Glisse <jglisse@xxxxxxxxxx> Cc: Rafael Aquini <aquini@xxxxxxxxxx> Cc: Yang Shi <shy828301@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/migrate.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/mm/migrate.c~mm-migratec-fix-potential-indeterminate-pte-entry-in-migrate_vma_insert_page +++ a/mm/migrate.c @@ -2947,6 +2947,13 @@ static void migrate_vma_insert_page(stru 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. + */ + pr_warn_once("Unsupported ZONE_DEVICE page type.\n"); + goto abort; } } else { entry = mk_pte(page, vma->vm_page_prot); _
