On Sat, 13 Sep 2025 20:33:50 -0700 SeongJae Park sj@kernel.org wrote:
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
FYI, the commit was able to be cleanly cherry-picked, but seems it caused a build error, similar to that [1] for 6.1.y. This patch fixes the build error.
[1] https://lore.kernel.org/20250914033221.49447-1-sj@kernel.org
Thanks, SJ
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