From: Quanmin Yan yanquanmin1@huawei.com
Patch series "mm/damon: avoid divide-by-zero in DAMON module's parameters application".
DAMON's RECLAIM and LRU_SORT modules perform no validation on user-configured parameters during application, which may lead to division-by-zero errors.
Avoid the divide-by-zero by adding validation checks when DAMON modules attempt to apply the parameters.
This patch (of 2):
During the calculation of 'hot_thres' and 'cold_thres', either 'sample_interval' or 'aggr_interval' is used as the divisor, which may lead to division-by-zero errors. Fix it by directly returning -EINVAL when such a case occurs. Additionally, since 'aggr_interval' is already required to be set no smaller than 'sample_interval' in damon_set_attrs(), only the case where 'sample_interval' is zero needs to be checked.
Link: https://lkml.kernel.org/r/20250827115858.1186261-2-yanquanmin1@huawei.com Fixes: 40e983cca927 ("mm/damon: introduce DAMON-based LRU-lists Sorting") 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 [6.0+] Signed-off-by: Andrew Morton akpm@linux-foundation.org (cherry picked from commit 711f19dfd783ffb37ca4324388b9c4cb87e71363) Signed-off-by: SeongJae Park sj@kernel.org --- mm/damon/lru_sort.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/mm/damon/lru_sort.c b/mm/damon/lru_sort.c index 3de2916a65c3..b4032538b22c 100644 --- a/mm/damon/lru_sort.c +++ b/mm/damon/lru_sort.c @@ -203,6 +203,9 @@ static int damon_lru_sort_apply_parameters(void) unsigned int hot_thres, cold_thres; int err = 0;
+ if (!damon_lru_sort_mon_attrs.sample_interval) + return -EINVAL; + err = damon_set_attrs(ctx, &damon_lru_sort_mon_attrs); if (err) return err;