CVE-2025-39909

In the Linux kernel, the following vulnerability has been resolved:

mm/damon/lrusort: avoid divide-by-zero in damonlrusortapply_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 'hotthres' and 'coldthres', either 'sampleinterval' or 'aggrinterval' 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 'aggrinterval' is already required to be set no smaller than 'sampleinterval' in damonsetattrs(), only the case where 'sample_interval' is zero needs to be checked.