CVE-2026-64458
mm/damon/ops-common: handle extreme intervals in damon_hot_score()
In the Linux kernel, the following vulnerability has been resolved: mm/damon/ops-common: handle extreme intervals in damon_hot_score() Fix three issues in damon_hot_score() that comes from wrong handling of extreme (zero or too high) monitoring intervals user setup. When the user sets sampling interval zero, damon_max_nr_accesses(), which is called from damon_hot_score(), causes a divide-by-zero. Needless to say, it is a problem. When the user sets the aggregation interval zero, the function returns zero. It is wrong, since the real maximum nr_acceses in the setup should be one. Worse yet, it can cause another divide-by-zero from its caller, damon_hot_score(), since it uses damon_max_nr_accesses() return value as a denominator. When the user sets the aggregation interval very high, damon_hot_score() could return a value out of [0, DAMOS_MAX_SCORE] range. Since the return value is used as an index to the regions_score_histogram array, which is DAMOS_MAX_SCORE+1 size, it causes out of bounds array access. The issues can be relatively easily reproduced like below. The sysfs write permission is required, though. # ./damo start --damos_action lru_prio --damos_quota_space 100M \ --damos_quota_interval 1s # cd /sys/kernel/mm/damon/admin/kdamonds/0 # echo 0 > contexts/0/monitoring_attrs/intervals/sample_us # echo 0 > contexts/0/monitoring_attrs/intervals/aggr_us # echo commit > state # dmesg [...] [ 131.329762] Oops: divide error: 0000 [#1] SMP NOPTI [...] [ 131.336089] RIP: 0010:damon_hot_score+0x27/0xd0 [...] Fix the divide-by-zero intervals problems by explicitly handling the zero intervals in damon_max_nr_accesses(). Fix the out-of-bound array access by applying [0, DAMOS_MAX_SCORE] bounds before returning from damon_hot_score(). The issue was discovered [1] by Sashiko.
Fixes and workarounds
Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| Linux Linux |
≥ 198f0f4c58b9f481e4e51c8c70a6ab9852bbab7f; < 58321b4e6e4f0f412069ab27ccdd56292757343a (affected, git) ≥ 198f0f4c58b9f481e4e51c8c70a6ab9852bbab7f; < 74fef68d521150281e36cdaa20e9e1ee3e3aa146 (affected, git) ≥ 198f0f4c58b9f481e4e51c8c70a6ab9852bbab7f; < ef2ae10a4582bc92b7e944181bbd2f87f3d30f3a (affected, git) ≥ 198f0f4c58b9f481e4e51c8c70a6ab9852bbab7f; < 9c8f31eaae6140ecadec0c07320498a944556de2 (affected, git) ≥ 198f0f4c58b9f481e4e51c8c70a6ab9852bbab7f; < 76e415ea88d20f022ed5cfcf78c50e156a267e91 (affected, git) ≥ 198f0f4c58b9f481e4e51c8c70a6ab9852bbab7f; < 35d4a3cf70a855b50e53189ac2f8463e20a02046 (affected, git) Other versions: unaffected |
CNA: Linux |
| Linux Linux |
5.16 (affected) ≥ 0; < 5.16 (unaffected, semver) ≥ 6.1.178; ≤ 6.1.* (unaffected, semver) ≥ 6.6.145; ≤ 6.6.* (unaffected, semver) ≥ 6.12.96; ≤ 6.12.* (unaffected, semver) ≥ 6.18.39; ≤ 6.18.* (unaffected, semver) ≥ 7.1.4; ≤ 7.1.* (unaffected, semver) ≥ 7.2; ≤ * (unaffected, original_commit_for_fix) Other versions: affected |
CNA: Linux |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
NVD applicability configurations (1)
These expressions retain AND/OR operators, negation, and required environmental products. A listed product is not sufficient to establish exposure when additional conditions apply.
[
{
"negate": false,
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.178",
"versionStartIncluding": "5.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.145",
"versionStartIncluding": "6.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.96",
"versionStartIncluding": "6.7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.39",
"versionStartIncluding": "6.13",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.4",
"versionStartIncluding": "6.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.2:rc1:*:*:*:*:*:*",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:7.2:rc2:*:*:*:*:*:*",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
],
"operator": "OR"
}
]CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 5.5 medium |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H | NVD: [email protected] |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://git.kernel.org/stable/c/58321b4e6e4f0f412069ab27ccdd56292757343aCNA: Linux
- https://git.kernel.org/stable/c/74fef68d521150281e36cdaa20e9e1ee3e3aa146CNA: Linux
- https://git.kernel.org/stable/c/ef2ae10a4582bc92b7e944181bbd2f87f3d30f3aCNA: Linux
- https://git.kernel.org/stable/c/9c8f31eaae6140ecadec0c07320498a944556de2CNA: Linux
- https://git.kernel.org/stable/c/76e415ea88d20f022ed5cfcf78c50e156a267e91CNA: Linux
- https://git.kernel.org/stable/c/35d4a3cf70a855b50e53189ac2f8463e20a02046CNA: Linux
- https://git.kernel.org/stable/c/35d4a3cf70a855b50e53189ac2f8463e20a02046416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
- https://git.kernel.org/stable/c/58321b4e6e4f0f412069ab27ccdd56292757343a416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
- https://git.kernel.org/stable/c/74fef68d521150281e36cdaa20e9e1ee3e3aa146416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
- https://git.kernel.org/stable/c/76e415ea88d20f022ed5cfcf78c50e156a267e91416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
- https://git.kernel.org/stable/c/9c8f31eaae6140ecadec0c07320498a944556de2416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
- https://git.kernel.org/stable/c/ef2ae10a4582bc92b7e944181bbd2f87f3d30f3a416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
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