Bug 2400613 (CVE-2025-39909) - CVE-2025-39909 kernel: mm/damon/lru_sort: avoid divide-by-zero in damon_lru_sort_apply_parameters()
Summary: CVE-2025-39909 kernel: mm/damon/lru_sort: avoid divide-by-zero in damon_lru_s...
Keywords:
Status: NEW
Alias: CVE-2025-39909
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
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Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-10-01 08:02 UTC by OSIDB Bzimport
Modified: 2025-11-26 11:27 UTC (History)
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Description OSIDB Bzimport 2025-10-01 08:02:35 UTC
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.


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