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

mm/damon/core: error damos_commit_quota_goal() for zero target_value

Patch series "mm/damon: move zero damos quota target_value handling to the
core layer".

Having zero DAMOS quota target value can cause division by zero. DAMON
API callers are checking the target value parameters to avoid that. It is
easy to make mistakes in some of the multiple API callers. Move that to
the core layer.

Patch 1 adds the corner case handling into the core layer DAMON parameters
validation logic. Patches 2 and 3 remove no more needed DAMON API callers
side handling of the corner case in DAMON_LRU_SORT and DMON_SAMPLIE_MTIER,
respectively.


This patch (of 3):

If a DAMOS scheme has a damos_quota_goal of zero target_value,
damos_quota_goal() could trigger division-by-zero error. Hence each DAMON
API callers should do the zero target_value validation. It is easy to
make mistakes. Actually such bugs in DAMON_LRU_SORT and
DAMON_SAMPLE_MTIER were found and fixed [1].

It is better to handle the corner case only once in the core layer,
instead of multiple places in all DAMON API callers. One straightforward
option is using an alternative denominator for the corner case in the
damos_quota_goal(). However, the zero target_value is meaningless. In
this case, the quota goal is always evaluated as achieved or
over-achieved. The quota will only keep being reduced.

Simply avoid using zero target_value by adding a check in the core layer
DAMOS quota goal parameters validation/commit path,
damos_commit_quota_goal(). Update it to return an error in the case.
Also update its caller to propagate the error.
Published: 2026-11-02
Score: n/a
EPSS: n/a
KEV: No
Impact: Division by Zero in Kernel
Action: Immediate Patch
AI Analysis

Impact

This vulnerability arises in the Linux kernel's DAMON subsystem when a zero target_value is supplied to damos_commit_quota_goal(), causing a division-by-zero error. The core logic fails to validate this corner case, leading to an undefined operation that can crash the kernel or render the system unstable. If an attacker has the ability to invoke DAMON APIs, they could trigger a kernel OOPS or a denial‑of‑service by supplying a zero target value. The weakness is a typical divide‑by‑zero error that can be exploited if the affected interface is reachable from untrusted contexts.

Affected Systems

The flaw affects all Linux kernel builds that include the DAMON feature, specifically those using the mm/damon implementation. The issue was addressed by patching the core layer and removing the defensive checks from individual API callers. Users operating recent kernels incorporating the mm/damon patch series have the fix; older kernels lacking this change remain susceptible.

Risk and Exploitability

No CVSS score or EPSS value is published for this CVE, and it is not listed in the CISA KEV catalog. However, the flaw can be triggered by any user with access to DAMON API calls, potentially leading to a kernel crash. The lack of external proof of exploitation suggests current risk may be moderate, but the absence of mitigations on many distributions means a vulnerable system could be compromised if an attacker can reach the API. Upgrading to a kernel that includes the patch is the recommended path to eliminate the risk.

Generated by OpenCVE AI on November 2, 2026 at 17:51 UTC.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Update the Linux kernel to a release that contains the DAMON parameter validation patch series
  • If custom kernel builds are used, rebuild DAMON with the updated core layer that checks target_value for zero
  • Ensure that all applications configuring DAMON quotas specify non‑zero target_value to avoid encountering the divisor issue

Generated by OpenCVE AI on November 2, 2026 at 17:51 UTC.

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History

Mon, 02 Nov 2026 19:15:00 +0000

Type Values Removed Values Added
First Time appeared Linux linux
Vendors & Products Linux linux

Mon, 02 Nov 2026 18:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-369

Mon, 02 Nov 2026 16:15:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: mm/damon/core: error damos_commit_quota_goal() for zero target_value Patch series "mm/damon: move zero damos quota target_value handling to the core layer". Having zero DAMOS quota target value can cause division by zero. DAMON API callers are checking the target value parameters to avoid that. It is easy to make mistakes in some of the multiple API callers. Move that to the core layer. Patch 1 adds the corner case handling into the core layer DAMON parameters validation logic. Patches 2 and 3 remove no more needed DAMON API callers side handling of the corner case in DAMON_LRU_SORT and DMON_SAMPLIE_MTIER, respectively. This patch (of 3): If a DAMOS scheme has a damos_quota_goal of zero target_value, damos_quota_goal() could trigger division-by-zero error. Hence each DAMON API callers should do the zero target_value validation. It is easy to make mistakes. Actually such bugs in DAMON_LRU_SORT and DAMON_SAMPLE_MTIER were found and fixed [1]. It is better to handle the corner case only once in the core layer, instead of multiple places in all DAMON API callers. One straightforward option is using an alternative denominator for the corner case in the damos_quota_goal(). However, the zero target_value is meaningless. In this case, the quota goal is always evaluated as achieved or over-achieved. The quota will only keep being reduced. Simply avoid using zero target_value by adding a check in the core layer DAMOS quota goal parameters validation/commit path, damos_commit_quota_goal(). Update it to return an error in the case. Also update its caller to propagate the error.
Title mm/damon/core: error damos_commit_quota_goal() for zero target_value
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-11-02T16:06:43.703Z

Reserved: 2026-09-25T10:25:14.403Z

Link: CVE-2026-99240

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-11-02T16:17:49.773

Modified: 2026-11-02T16:17:49.773

Link: CVE-2026-99240

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-11-02T19:00:06Z

Weaknesses