[PATCH v4 0/2] mm,hwpoison: fix sending SIGBUS for Action Required MCE

[Naoya Horiguchi <nao.horiguchi@gmail.com>]

Hi,

I updated the series based on Boris's review.  I folded 2/3 and 3/3
into one patch, updated description, added some refactored and rebased
onto v5.12.  There's no essential change in how the problem is solved.

v1: https://lore.kernel.org/linux-mm/20210412224320.1747638-1-nao.horiguchi@gmail.com/
v2 (only 3/3 is posted): https://lore.kernel.org/linux-mm/20210419023658.GA1962954@u2004/
v3: https://lore.kernel.org/linux-mm/20210421005728.1994268-1-nao.horiguchi@gmail.com/

Thanks,
Naoya Horiguchi

--- quote from cover letter of v1 ---

I wrote this patchset to materialize what I think is the current
allowable solution mentioned by the previous discussion [1].
I simply borrowed Tony's mutex patch and Aili's return code patch,
then I queued another one to find error virtual address in the best
effort manner.  I know that this is not a perfect solution, but
should work for some typical case.

[1]: https://lore.kernel.org/linux-mm/20210331192540.2141052f@alex-virtual-machine/
---
Summary:

Naoya Horiguchi (1):
      mm,hwpoison: send SIGBUS when the page has already been poisoned

Tony Luck (1):
      mm/memory-failure: Use a mutex to avoid memory_failure() races

 arch/x86/kernel/cpu/mce/core.c |  13 ++-
 include/linux/swapops.h        |   5 ++
 mm/memory-failure.c            | 180 +++++++++++++++++++++++++++++++++++++----
 3 files changed, 182 insertions(+), 16 deletions(-)