mm/damon/core: error damos_commit_quota_goal() for zero target_value
Affects Linux kernel DAMON when a DAMOS scheme uses a quota goal with a zero target_value, in kernels before 6.18.60, 7.2.14, and 7.3.1. Fixed in those releases.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 6.18.60, 7.2.14, 7.3.1
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. A DAMOS scheme has a quota goal with a zero target_value. Requires sysfs write permission and certain DAMON ABI usages. Requires a rare race timing.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 25/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Fix
- Fixed in 6.18.60, 7.2.14, 7.3.1
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
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.
What to do
Check whether your setup matches what the bug needs.
A DAMOS scheme has a quota goal with a zero target_value. Requires sysfs write permission and certain DAMON ABI usages. Requires a rare race timing.Upgrade to a fixed version: 6.18.60, 7.2.14, 7.3.1.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- Linux Linux
fixed in 6.18.60; fixed in 7.2.14; fixed in 7.3.1
- Linux Linux
Version range not reported
Evidence 3
- Link
- Link
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-99240
What does this mean?
A race condition in the DAMON memory-management code can cause a divide-by-zero error when a DAMOS scheme has a quota goal with a zero target_value.Source: git.kernel.org
Am I affected, and how do I check?
Linux kernel versions before 6.18.60, 7.2.14, and 7.3.1 are listed as affected. The bug needs a DAMOS scheme with a quota goal whose target_value is zero, plus sysfs write permission, certain DAMON ABI usage, and a rare race timing. Check your kernel version with uname -r and review DAMOS quota goal settings in the DAMON sysfs interface.Source: git.kernel.org
What should I do about it?
Upgrade to Linux 6.18.60, 7.2.14, 7.3.1, or a later release in the matching stable branch.Source: git.kernel.org
Is it being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data