CVE-2025-39909: mm/damon/lru_sort: avoid divide-by-zero in damon_lru_sort_apply_parameters()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-10-01 · updated 2026-10-19
Weakness: CWE-369

Description

In the Linux kernel, the following vulnerability has been resolved: mm/damon/lru_sort: avoid divide-by-zero in damon_lru_sort_apply_parameters() 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.

Affected products

Debian Linux: 11.0
Linux kernel: from 6.0 before 6.1.153; from 6.2 before 6.6.107; from 6.7 before 6.12.48; from 6.13 before 6.16.8; 6.17-rc1, 6.17-rc2, 6.17-rc3, 6.17-rc4, 6.17-rc5 — fixed in 6.1.153, 6.12.48, 6.16.8, 6.6.107

How to fix

Upgrade to a fixed version: Linux kernel 6.1.153, 6.12.48, 6.16.8, 6.6.107. Check the vendor advisory for mitigations.

References

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