mm/damon/core: avoid infinite kdamond_merge_regions() internal loop
In the Linux kernel, the following vulnerability has been resolved: mm/damon/core: avoid infinite kdamond_merge_regions() internal loop Patch series "mm/damon: unurgent fixes for infinite loop, NULL de-ref and races", v1.1. Sashiko found a few issues in DAMON that could cause infinite loop, NULL dereference and monitoring results degradation. The first two sounds scary but the infinite loop happens only under unreasonable user setup. The NULL dereference is only in a unit test. Monitoring results degradation is trivial since it is only best-effort, and those happens from only unlikely races. Still those are bugs that better to fix if possible. Fix those. This patch (of 6): Due to online parameter update like events, the number of DAMON regions could be higher than the user-set upper limit. kdamond_merge_regions() repeats merge regions until the number meets the limit, while doubling the merge threshold up to the theoretical maximum threshold. It is tried only up to the theoretical maximum threshold because even the aggressive merging can fail from reducing the number of regions under the user-defined upper limit. For example, there could be many user-defined non-contiguous regions that cannot be merged. The threshold based loop break condition is evaluated by comparing the threshold for the next merging try against the theoretical maximum threshold. If max_thres is larger than UINT_MAX / 2, doubling the threshold could make it overflow, and bypass the loop break condition. In
- Products
- Kernel
- Affected versions
- Not specified
- Fixed versions
- 5.15.222, 6.1.189, 6.12.111, 6.18.53, 6.6.158, 7.2.5
- CVEs
- CVE-2026-89796
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 15:07 UTC · Revision 1
Source evidence
mm/damon/core: avoid infinite kdamond_merge_regions() internal loop
core-osv · Original sourcePublished 16 Sept 2026, 10:30 UTC
In the Linux kernel, the following vulnerability has been resolved: mm/damon/core: avoid infinite kdamond_merge_regions() internal loop Patch series "mm/damon: unurgent fixes for infinite loop, NULL de-ref and races", v1.1. Sashiko found a few issues in DAMON that could cause infinite loop, NULL dereference and monitoring results degradation. The first two sounds scary but the infinite loop happens only under unreasonable user setup. The NULL dereference is only in a unit test. Monitoring results degradation is trivial since it is only best-effort, and those happens from only unlikely races. Still those are bugs that better to fix if possible. Fix those. This patch (of 6): Due to online parameter update like events, the number of DAMON regions could be higher than the user-set upper limit. kdamond_merge_regions() repeats merge regions until the number meets the limit, while doubling the merge threshold up to the theoretical maximum threshold. It is tried only up to the theoretical maximum threshold because even the aggressive merging can fail from reducing the number of regions under the user-defined upper limit. For example, there could be many user-defined non-contiguous regions that cannot be merged. The threshold based loop break condition is evaluated by comparing the threshold for the next merging try against the theoretical maximum threshold. If max_thres is larger than UINT_MAX / 2, doubling the threshold could make it overflow, and bypass the loop break condition. In
osv:CVE-2026-89796
Kernel
Fixed versions: 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2.5
Complete source record
{
"id": "86e080064263579cd20ff9b49fae1f74e01b37cbb52ab30f97e09fdef4d74f97",
"url": "https://osv.dev/vulnerability/CVE-2026-89796",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "mm/damon/core: avoid infinite kdamond_merge_regions() internal loop",
"summary": "In the Linux kernel, the following vulnerability has been resolved: mm/damon/core: avoid infinite kdamond_merge_regions() internal loop Patch series \"mm/damon: unurgent fixes for infinite loop, NULL de-ref and races\", v1.1. Sashiko found a few issues in DAMON that could cause infinite loop, NULL dereference and monitoring results degradation. The first two sounds scary but the infinite loop happens only under unreasonable user setup. The NULL dereference is only in a unit test. Monitoring results degradation is trivial since it is only best-effort, and those happens from only unlikely races. Still those are bugs that better to fix if possible. Fix those. This patch (of 6): Due to online parameter update like events, the number of DAMON regions could be higher than the user-set upper limit. kdamond_merge_regions() repeats merge regions until the number meets the limit, while doubling the merge threshold up to the theoretical maximum threshold. It is tried only up to the theoretical maximum threshold because even the aggressive merging can fail from reducing the number of regions under the user-defined upper limit. For example, there could be many user-defined non-contiguous regions that cannot be merged. The threshold based loop break condition is evaluated by comparing the threshold for the next merging try against the theoretical maximum threshold. If max_thres is larger than UINT_MAX / 2, doubling the threshold could make it overflow, and bypass the loop break condition. In",
"evidence": "osv:CVE-2026-89796",
"products": [
{
"name": {
"value": "Kernel",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "5.15.222",
"evidence": "/affected/1/ranges"
},
{
"value": "6.1.189",
"evidence": "/affected/1/ranges"
},
{
"value": "6.6.158",
"evidence": "/affected/1/ranges"
},
{
"value": "6.12.111",
"evidence": "/affected/1/ranges"
},
{
"value": "6.18.53",
"evidence": "/affected/1/ranges"
},
{
"value": "7.2.5",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
}
],
"severity": "unknown",
"structured": {
"id": "CVE-2026-89796",
"aliases": [
"CVE-2026-89796"
],
"affected": [
{
"ranges": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "1e865019cef354a5f0314491b4b4fc9f9a613642"
},
{
"fixed": "407da1dd7f48e5ba22ceb8834f6923390632d025"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "d7eda72e59bbf3ed592db7ff0fd8c246c73149a8"
},
{
"fixed": "65edd8b3a88278c9f8e5c7d8c15d4f296ce35078"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "11078e2d11465518a9e85096bd28f8cd5fa1ea41"
},
{
"fixed": "5b0953f86d65855dc901050f40bbe6da0475d198"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "310d6c15e9104c99d5d9d0ff8e5383a79da7d5e6"
},
{
"fixed": "769c16699c89811386eb003c8fd9dcb8d405b316"
},
{
"fixed": "50a7a5aec1aa43efc297fd4377c1cbdc7d15620d"
},
{
"fixed": "8a96a06e04d210845be5d9581c0e9e338947e8f8"
},
{
"fixed": "123e4619ab6c8ab1c4cb1d7a58311a2af13929cd"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "5.15.164"
},
{
"fixed": "5.15.222"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "6.1.101"
},
{
"fixed": "6.1.189"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "6.6.41"
},
{
"fixed": "6.6.158"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "6.9.10"
},
{
"fixed": "6.10"
}
]
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"type": "GIT",
"events": [
{
"introduced": "f2bd3184b6aeca6a497394b558337246e09fc02d"
}
]
}
],
"versions": [
"v5.15.221",
"v5.15.220",
"v5.15.219",
"v5.15.218",
"v5.15.217",
"v5.15.216",
"v5.15.215",
"v5.15.214",
"v5.15.213",
"v5.15.212",
"v5.15.211",
"v5.15.210",
"v5.15.209",
"v5.15.208",
"v5.15.207",
"v5.15.206",
"v5.15.205",
"v5.15.204",
"v5.15.203",
"v5.15.202",
"v5.15.201",
"v5.15.200",
"v5.15.199",
"v5.15.198",
"v5.15.197",
"v5.15.196",
"v5.15.195",
"v5.15.194",
"v5.15.193",
"v5.15.192",
"v5.15.191",
"v5.15.190",
"v5.15.189",
"v5.15.188",
"v5.15.187",
"v5.15.186",
"v5.15.185",
"v5.15.184",
"v5.15.183",
"v5.15.182",
"v5.15.181",
"v5.15.180",
"v5.15.179",
"v5.15.178",
"v5.15.177",
"v5.15.176",
"v5.15.175",
"v5.15.174",
"v5.15.173",
"v5.15.172",
"v5.15.171",
"v5.15.170",
"v5.15.169",
"v5.15.168",
"v5.15.167",
"v5.15.166",
"v5.15.165",
"v5.15.164",
"v6.1.188",
"v6.1.187",
"v6.1.186",
"v6.1.185",
"v6.1.184",
"v6.1.183",
"v6.1.182",
"v6.1.181",
"v6.1.180",
"v6.1.179",
"v6.1.178",
"v6.1.177",
"v6.1.176",
"v6.1.175",
"v6.1.174",
"v6.1.173",
"v6.1.172",
"v6.1.171",
"v6.1.170",
"v6.1.169",
"v6.1.168",
"v6.1.167",
"v6.1.166",
"v6.1.165",
"v6.1.164",
"v6.1.163",
"v6.1.162",
"v6.1.161",
"v6.1.160",
"v6.1.159",
"v6.1.158",
"v6.1.157",
"v6.1.156",
"v6.1.155",
"v6.1.154",
"v6.1.153",
"v6.1.152",
"v6.1.151",
"v6.1.150",
"v6.1.149",
"v6.1.148",
"v6.1.147",
"v6.1.146",
"v6.1.145",
"v6.1.144",
"v6.1.143",
"v6.1.142",
"v6.1.141",
"v6.1.140",
"v6.1.139",
"v6.1.138",
"v6.1.137",
"v6.1.136",
"v6.1.135",
"v6.1.134",
"v6.1.133",
"v6.1.132",
"v6.1.131",
"v6.1.130",
"v6.1.129",
"v6.1.128",
"v6.1.127",
"v6.1.126",
"v6.1.125",
"v6.1.124",
"v6.1.123",
"v6.1.122",
"v6.1.121",
"v6.1.120",
"v6.1.119",
"v6.1.118",
"v6.1.117",
"v6.1.116",
"v6.1.115",
"v6.1.114",
"v6.1.113",
"v6.1.112",
"v6.1.111",
"v6.1.110",
"v6.1.109",
"v6.1.108",
"v6.1.107",
"v6.1.106",
"v6.1.105",
"v6.1.104",
"v6.1.103",
"v6.1.102",
"v6.1.101",
"v6.6.157",
"v6.6.156",
"v6.6.155",
"v6.6.154",
"v6.6.153",
"v6.6.152",
"v6.6.151",
"v6.6.150",
"v6.6.149",
"v6.6.148",
"v6.6.147",
"v6.6.146",
"v6.6.145",
"v6.6.144",
"v6.6.143",
"v6.6.142",
"v6.6.141",
"v6.6.140",
"v6.6.139",
"v6.6.138",
"v6.6.137",
"v6.6.136",
"v6.6.135",
"v6.6.134",
"v6.6.133",
"v6.6.132",
"v6.6.131",
"v6.6.130",
"v6.6.129",
"v6.6.128",
"v6.6.127",
"v6.6.126",
"v6.6.125",
"v6.6.124",
"v6.6.123",
"v6.6.122",
"v6.6.121",
"v6.6.120",
"v6.6.119",
"v6.6.118",
"v6.6.117",
"v6.6.116",
"v6.6.115",
"v6.6.114",
"v6.6.113",
"v6.6.112",
"v6.6.111",
"v6.6.110",
"v6.6.109",
"v6.6.108",
"v6.6.107",
"v6.6.106",
"v6.6.105",
"v6.6.104",
"v6.6.103",
"v6.6.102",
"v6.6.101",
"v6.6.100",
"v6.6.99",
"v6.6.98",
"v6.6.97",
"v6.6.96",
"v6.6.95",
"v6.6.94",
"v6.6.93",
"v6.6.92",
"v6.6.91",
"v6.6.90",
"v6.6.89",
"v6.6.88",
"v6.6.87",
"v6.6.86",
"v6.6.85",
"v6.6.84",
"v6.6.83",
"v6.6.82",
"v6.6.81",
"v6.6.80",
"v6.6.79",
"v6.6.78",
"v6.6.77",
"v6.6.76",
"v6.6.75",
"v6.6.74",
"v6.6.73",
"v6.6.72",
"v6.6.71",
"v6.6.70",
"v6.6.69",
"v6.6.68",
"v6.6.67",
"v6.6.66",
"v6.6.65",
"v6.6.64",
"v6.6.63",
"v6.6.62",
"v6.6.61",
"v6.6.60",
"v6.6.59",
"v6.6.58",
"v6.6.57",
"v6.6.56",
"v6.6.55",
"v6.6.54",
"v6.6.53",
"v6.6.52",
"v6.6.51",
"v6.6.50",
"v6.6.49",
"v6.6.48",
"v6.6.47",
"v6.6.46",
"v6.6.45",
"v6.6.44",
"v6.6.43",
"v6.6.42",
"v6.6.41",
"v6.9.12",
"v6.9.11",
"v6.9.10"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89796.json"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "5.15.222"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "5.16.0"
},
{
"fixed": "6.1.189"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.2.0"
},
{
"fixed": "6.6.158"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.7.0"
},
{
"fixed": "6.12.111"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.10.0"
},
{
"fixed": "6.18.53"
}
]
},
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "6.13.0"
},
{
"fixed": "7.2.5"
}
]
}
],
"package": {
"name": "Kernel",
"ecosystem": "Linux"
},
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89796.json"
}
}
],
"modified": "2026-10-28T02:30:36.748193068Z",
"provider": "osv",
"references": [
"https://git.kernel.org/stable/c/123e4619ab6c8ab1c4cb1d7a58311a2af13929cd",
"https://git.kernel.org/stable/c/407da1dd7f48e5ba22ceb8834f6923390632d025",
"https://git.kernel.org/stable/c/50a7a5aec1aa43efc297fd4377c1cbdc7d15620d",
"https://git.kernel.org/stable/c/5b0953f86d65855dc901050f40bbe6da0475d198",
"https://git.kernel.org/stable/c/65edd8b3a88278c9f8e5c7d8c15d4f296ce35078",
"https://git.kernel.org/stable/c/769c16699c89811386eb003c8fd9dcb8d405b316",
"https://git.kernel.org/stable/c/8a96a06e04d210845be5d9581c0e9e338947e8f8",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89796.json",
"https://nvd.nist.gov/vuln/detail/CVE-2026-89796",
"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
],
"provider_metadata": {
"cna_assigner": "Linux",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89796.json"
}
},
"related_cves": [
{
"value": "CVE-2026-89796",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": null
},
"source_id": "core-osv",
"document_id": 504012,
"published_at": "2026-09-16T10:30:27.478+00:00"
}