Commit d8f867fa0825 ("mm/damon: add damon_ctx->min_sz_region") introduced a bug that allows unaligned DAMON region address ranges. Commit c80f46ac228b ("mm/damon/core: disallow non-power of two min_region_sz") fixed it, but only for damon_commit_ctx() use case. Still, DAMON sysfs interface can emit non-power of two min_region_sz via damon_start(). Fix the path by adding the is_power_of_2() check on damon_start(). The issue was discovered by sashiko [1]. [1] https://lore.kernel.org/20260403155530.64647-1-sj@kernel.org Fixes: d8f867fa0825 ("mm/damon: add damon_ctx->min_sz_region") Cc: # 6.18.x Signed-off-by: SeongJae Park --- mm/damon/core.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/mm/damon/core.c b/mm/damon/core.c index 3703f62a876b3..c107d74c77e74 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -1368,6 +1368,11 @@ int damon_start(struct damon_ctx **ctxs, int nr_ctxs, bool exclusive) int i; int err = 0; + for (i = 0; i < nr_ctxs; i++) { + if (!is_power_of_2(ctxs[i]->min_region_sz)) + return -EINVAL; + } + mutex_lock(&damon_lock); if ((exclusive && nr_running_ctxs) || (!exclusive && running_exclusive_ctxs)) { base-commit: 872b6168e577ea326324255fa8b6716a89124680 -- 2.47.3