[PATCH v3 0/2] mm/damon: validate min_region_size to be power of 2

[Liew Rui Yan <aethernet65535@gmail.com>]

Problem
=======
When a user provides an invalid min_region_sz (not a power-of-2) via the
DAMON sysfs interface, damon_commit_ctx() fails the validation, which
causes the kdamond to terminate unexpectedly.

Reproduction steps:
1. Enable DAMON_LRU_SORT or DAMON_RECLAIM.
2. Set an invalid 'min_region_sz' by setting 'addr_unit' such that
   'DAMON_MIN_REGION_SZ / addr_unit' is not a power-of-2 (e.g.,
   addr_unit=3).
3. Commit the parameters via 'commit_inputs'.
4. kdamond terminates due to the validation failure.

Solution
========
Add power-of-2 validation in damon_lru_sort_apply_parameters() and
damon_reclaim_apply_parameters(), return -EINVAL immediately.

Patch 1 fixes the issue for DAMON_LRU_SORT.
Patch 2 fixes the issue for DAMON_RECLAIM.

Changes from v2
(https://lore.kernel.org/20260402053756.26606-1-aethernet65535@gmail.com)
- Split the patch into two per-module patches.
- Add Fixes: and Cc: stable tags.
- Elaborate user impact and reproduction steps.
Changes from v1
(https://lore.kernel.org/20260331073231.30060-1-aethernet65535@gmail.com)
- Fix memory leak issue.
Changes from first attempt
(https://lore.kernel.org/20260327062627.66426-1-aethernet65535@gmail.com)
- Renamed the subject.
- Validate min_region_sz rather than addr_unit.

Liew Rui Yan (2):
  mm/damon/lru_sort: validate min_region_size to be power of 2
  mm/damon/reclaim: validate min_region_size to be power of 2

 mm/damon/lru_sort.c | 5 +++++
 mm/damon/reclaim.c  | 5 +++++
 2 files changed, 10 insertions(+)

-- 
2.53.0