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mm/damon/lru_sort: avoid divide-by-zero in damon_lru_sort_apply_parameters() 

commit 711f19dfd7 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: 40e983cca9 ("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>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Quanmin Yan 2025-08-27 19:58:57 +08:00 committed by Greg Kroah-Hartman
parent 64dc351e58
commit 74e391f7da
1 changed files with 3 additions and 0 deletions
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3
mm/damon/lru_sort.c
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@ -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;