This series aim at the following enhancement -
- Let one hwpoison injector, that is, madvise(MADV_HWPOISON) to behave
more like as if a real UE occurred. Because the other two injectors
such as hwpoison-inject and the 'einj' on x86 can't, and it seems to
me we need a better simulation to real UE scenario.
- For years, if the kernel is unable to unmap a hwpoisoned page, it send
a SIGKILL instead of SIGBUS to prevent user process from potentially
accessing the page again. But in doing so, the user process also lose
important information: vaddr, for recovery. Fortunately, the kernel
already has code to kill process re-accessing a hwpoisoned page, so
remove the '!unmap_success' check.
- Right now, if a thp page under GUP longterm pin is hwpoisoned, and
kernel cannot split the thp page, memory-failure simply ignores
the UE and returns. That's not ideal, it could deliver a SIGBUS with
useful information for userspace recovery.
Changes in v2:
- rebased to mm-stable as of 5/8/2024
- added RB by Oscar Salvador
- comments from Oscar on patch 1-of-3: clarify changelog
- comments from Miahe Lin on patch 3-of-3: remove unnecessary user page
checking and remove incorrect put_page() in kill_procs_now().
Invoke kill_procs_now() regardless MF_ACTIN_REQUIRED is set or not,
moved hwpoison_filter() higher up.
- added two patches 3-of-5 and 4-of-5
Jane Chu (5):
mm/memory-failure: try to send SIGBUS even if unmap failed
mm/madvise: Add MF_ACTION_REQUIRED to madvise(MADV_HWPOISON)
mm/memory-failure: improve memory failure action_result messages
mm/memory-failure: move hwpoison_filter() higher up
mm/memory-failure: send SIGBUS in the event of thp split fail
include/linux/mm.h | 2 +
include/ras/ras_event.h | 2 +
mm/madvise.c | 2 +-
mm/memory-failure.c | 89 +++++++++++++++++++++++++++--------------
4 files changed, 65 insertions(+), 30 deletions(-)
--
2.39.3
