The patch titled Subject: mm/damon/lru_sort: avoid divide-by-zero in damon_lru_sort_apply_parameters() has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-damon-lru_sort-avoid-divide-by-zero-in-damon_lru_sort_apply_parameters.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Quanmin Yan yanquanmin1@huawei.com Subject: mm/damon/lru_sort: avoid divide-by-zero in damon_lru_sort_apply_parameters() Date: Wed, 27 Aug 2025 19:58:57 +0800

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 ---

mm/damon/lru_sort.c | 5 +++++ 1 file changed, 5 insertions(+)

--- a/mm/damon/lru_sort.c~mm-damon-lru_sort-avoid-divide-by-zero-in-damon_lru_sort_apply_parameters +++ a/mm/damon/lru_sort.c @@ -198,6 +198,11 @@ static int damon_lru_sort_apply_paramete if (err) return err;

+ if (!damon_lru_sort_mon_attrs.sample_interval) { + err = -EINVAL; + goto out; + } + err = damon_set_attrs(ctx, &damon_lru_sort_mon_attrs); if (err) goto out; _

Patches currently in -mm which might be from yanquanmin1@huawei.com are

mm-damon-core-prevent-unnecessary-overflow-in-damos_set_effective_quota.patch mm-damon-lru_sort-avoid-divide-by-zero-in-damon_lru_sort_apply_parameters.patch mm-damon-reclaim-avoid-divide-by-zero-in-damon_reclaim_apply_parameters.patch