[PATCH v5 0/5] mm: Fix MF_DELAYED handling on memory failure

[Lisa Wang <wyihan@google.com>]

Here's a fifth revision to fix MF_DELAYED handling on memory failure.

This patch series addresses an issue in the memory failure handling path
where MF_DELAYED is incorrectly treated as an error. This issue was
discovered while testing memory failure handling for guest_memfd.

The proposed solution involves -
1. Clarifying the definition of MF_DELAYED to mean that memory failure
   handling is only partially completed, and that the metadata for the
   memory that failed (as in struct page/folio) is still referenced.
2. Updating shmem’s handling to align with the clarified definition.
3. Updating how the result of .error_remove_folio() is interpreted.

Changes from v4:
+ Add "fallthrough;" in the memory-failure test, as suggested by David
+ Add Fixes tags in the commit message, as suggested by Miaohe
+ Rebase to the branch "mm-stable"
+ Split the KVM selftests to the future series

Thanks for review from Ackerley, Andrew, David and Miaohe!

+ RFC v4: https://lore.kernel.org/all/20260602-memory-failure-mf-delayed-fix-v4-0-a5bc7db5a9b2@google.com/

Signed-off-by: Lisa Wang <wyihan@google.com>
---
Lisa Wang (5):
      mm: memory_failure: Clarify the MF_DELAYED definition
      mm: memory_failure: Allow truncate_error_folio to return MF_DELAYED
      mm: shmem: Update shmem handler to the MF_DELAYED definition
      mm: memory_failure: Generalize extra_pins handling to all MF_DELAYED cases
      mm: selftests: Add shmem into memory failure test

 mm/memory-failure.c                         |  29 ++++---
 mm/shmem.c                                  |   2 +-
 tools/testing/selftests/mm/memory-failure.c | 118 +++++++++++++++++++++++++++-
 3 files changed, 130 insertions(+), 19 deletions(-)
---
base-commit: 08745c62350126bc31b09548137be87e2866f628
change-id: 20260527-memory-failure-mf-delayed-fix-7d5a8f4a8a8b

Best regards,
-- 
Lisa Wang <wyihan@google.com>