[PATCH 0/4] hwpoison fixes for v4.2

[Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>]

There are some long-standing issues on hwpoison, so this patchset mentions
them. I explain details about each bug in individual patches. In summary:

Patch 1: fix the wrong behavior in failing thp split

Patch 2: fix inconsistent refcounting problem on thp tail pages

Patch 3: fix isolation in soft offlining with keeping refcount

Patch 4: potential fix for me_huge_page()

The user visible effects of patch 1 to 3 are kernel panic with BUG_ON,
so I believe that this patchset helps hwpoison to be more reliable.

This series is based on v4.1-rc3 + Xie XiuQi's patch "memory-failure:
export page_type and action result".

Thanks,
Naoya Horiguchi
---
Tree: https://github.com/Naoya-Horiguchi/linux/tree/v4.1-rc3/hwpoison_for_v4.2
---
Summary:

Naoya Horiguchi (4):
      mm/memory-failure: split thp earlier in memory error handling
      mm/memory-failure: introduce get_hwpoison_page() for consistent refcount handling
      mm: soft-offline: don't free target page in successful page migration
      mm/memory-failure: me_huge_page() does nothing for thp

 include/linux/mm.h   |   1 +
 mm/hwpoison-inject.c |   4 +-
 mm/memory-failure.c  | 164 +++++++++++++++++++--------------------------------
 mm/migrate.c         |   9 ++-
 mm/swap.c            |   2 -
 5 files changed, 70 insertions(+), 110 deletions(-)