mm/damon/reclaim: avoid divide-by-zero in damon_reclaim_apply_parameters()

When creating a new scheme of DAMON_RECLAIM, the calculation of
'min_age_region' uses 'aggr_interval' as the divisor, which may lead to
division-by-zero errors.  Fix it by directly returning -EINVAL when such a
case occurs.

Link: https://lkml.kernel.org/r/20250827115858.1186261-3-yanquanmin1@huawei.com
Fixes: f5a79d7c0c87 ("mm/damon: introduce struct damos_access_pattern")
Signed-off-by: Quanmin Yan <yanquanmin1@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: ze zuo <zuoze1@huawei.com>
Cc: <stable@vger.kernel.org>	[6.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/damon/reclaim.c b/mm/damon/reclaim.c
index 3c71b4596676753a35d322debddb154172377752..fb7c982a0018c2e5a2f8abcb4104e2119c4da440 100644 (file)
--- a/mm/damon/reclaim.c
+++ b/mm/damon/reclaim.c
@@ -194,6 +194,11 @@ static int damon_reclaim_apply_parameters(void)
        if (err)
                return err;
 
+       if (!damon_reclaim_mon_attrs.aggr_interval) {
+               err = -EINVAL;
+               goto out;
+       }
+
        err = damon_set_attrs(param_ctx, &damon_reclaim_mon_attrs);
        if (err)
                goto out;