From 74e391f7da7d9d5235a3cca88ee9fc18f720c75b Mon Sep 17 00:00:00 2001 From: Quanmin Yan Date: Wed, 27 Aug 2025 19:58:57 +0800 Subject: [PATCH] mm/damon/lru_sort: avoid divide-by-zero in damon_lru_sort_apply_parameters() commit 711f19dfd783ffb37ca4324388b9c4cb87e71363 upstream. 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 Reviewed-by: SeongJae Park Cc: Kefeng Wang Cc: ze zuo Cc: [6.0+] Signed-off-by: Andrew Morton Signed-off-by: SeongJae Park Signed-off-by: Greg Kroah-Hartman --- 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 98a678129b06..61311800abc9 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;