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[082/143] mm/migrate.c: fix potential indeterminate pte entry in migrate_vma_insert_page()

Message ID 20210505013710.tBHbfbSFt%akpm@linux-foundation.org (mailing list archive)
State New
Headers show
Series [001/143] mm: introduce and use mapping_empty() | expand

Commit Message

Andrew Morton May 5, 2021, 1:37 a.m. UTC
From: Miaohe Lin <linmiaohe@huawei.com>
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@huawei.com
Fixes: df6ad69838fc ("mm/device-public-memory: device memory cache coherent with CPU")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/migrate.c |    7 +++++++
 1 file changed, 7 insertions(+)
diff mbox series

Patch

--- 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);