From: Miaohe Lin linmiaohe@huawei.com

mainline inclusion from mainline-v5.13-rc1 commit 34f5e9b9d1990d286199084efa752530ee3d8297 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8HVSL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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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 Signed-off-by: Linus Torvalds torvalds@linux-foundation.org

conflict: mm/migrate.c

Signed-off-by: Tong Tiangen tongtiangen@huawei.com --- mm/migrate.c | 7 +++++++ 1 file changed, 7 insertions(+)

diff --git a/mm/migrate.c b/mm/migrate.c index dc6416ccef44..56a2033d443c 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2688,6 +2688,13 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate, if (vma->vm_flags & VM_WRITE) entry = pte_mkwrite(pte_mkdirty(entry)); entry = pte_mkdevmap(entry); + } else { + /* + * For now we not support migrating to MEMORY_DEVICE_FS_DAX + * and MEMORY_DEVICE_PCI_P2PDMA device memory. + */ + pr_warn_once("Unsupported ZONE_DEVICE page type.\n"); + goto abort; } } else { entry = mk_pte(page, vma->vm_page_prot);