[PATCH v1.1 0/6] mm/damon: unurgent fixes for infinite loop, NULL de-ref and races

[SJ Park]

Sashiko found a few issues in DAMON that could cause infinite loop, NULL
dereference and monitoring results degradation.  The first two sounds
scary but the infinite loop happens only under unreasonable user setup.
The NULL dereference is only in a unit test.  Monitoring results
degradation is trivial since it is only best-effort, and those happens
from only unlikely races.  Still those are bugs that better to fix if
possible. Fix those.

Changes from v1
- v1: https://lore.kernel.org/20260714135236.92699-1-sj@xxxxxxxxxx
- Add addr_unit race fix.
- Add Fixes: tags to the race fixes.
- Wordsmith subjects.
Changes from RFC v1.2
- RFC v1.2: https://lore.kernel.org/20260713135838.32730-1-sj@xxxxxxxxxx
- Drop RFC tag.
- Rebase to latest mm-new.
Changes from RFC v1.1
- RFC v1.1: https://lore.kernel.org/20260712170328.91144-1-sj@xxxxxxxxxx
- Remove same_target param from __damon_va_check_access().
Changes from RFC
- RFC: https://lore.kernel.org/20260711180409.82093-1-sj@xxxxxxxxxx
- Rebase to mm-new.

SJ Park (6):
  mm/damon/core: avoid infinite kdamond_merge_regions() internal loop
  mm/damon/tests/core-kunit: catch test failure in
    test_merge_regions_of()
  mm/damon/vaddr: drop last same folio access check optimization
  mm/damon/paddr: drop last same folio access check reuse optimization
  mm/damon/sysfs: read addr_unit only once in damon_sysfs_apply_inputs()
  mm/damon/sysfs: read ops_id only once in damon_sysfs_apply_inputs()

 mm/damon/core.c             | 13 +++++++++----
 mm/damon/paddr.c            | 20 ++++----------------
 mm/damon/sysfs.c            | 10 ++++++----
 mm/damon/tests/core-kunit.h |  3 +++
 mm/damon/vaddr.c            | 33 ++++++---------------------------
 5 files changed, 28 insertions(+), 51 deletions(-)


base-commit: 52d335d2c1de60b6184b9de5ecec634892a3e136
-- 
2.47.3