CVE-2026-80719 (GCVE-0-2026-80719)

Vulnerability from cvelistv5 – Published: 2026-08-28 06:53 – Updated: 2026-08-28 06:53
VLAI
Title
mm: mglru: fix stale batch updates after memcg reparenting
Summary
In the Linux kernel, the following vulnerability has been resolved: mm: mglru: fix stale batch updates after memcg reparenting The mglru page table walker batches per-generation size deltas in walk->nr_pages while walking page tables without holding the lruvec lock. The reset_batch_size() later folds those deltas into walk->lruvec under the lruvec lock. The page table walker can run concurrently with the memcg reparenting path as follows: CPU0 CPU1 ==== ==== walk_mm --> walk_page_range --> update_batch_size --> walk->nr_pages += delta mem_cgroup_css_offline --> memcg_reparent_objcgs --> lock lruvec lru_gen_reparent_memcg --> reparent child folios to parent unlock lruvec lock lruvec reset_batch_size --> child lrugen->nr_pages += delta This will trigger the following warning in lru_gen_exit_memcg(): VM_WARN_ON_ONCE(memchr_inv(lruvec->lrugen.nr_pages, 0, sizeof(lruvec->lrugen.nr_pages))); And the user-visible impact of underestimated nr_pages in MGLRU was premature OOMs because MGLRU does not try to reclaim memory when nr_pages reaches zero, but there are still more pages. To fix it, make reset_batch_size() check CSS_DYING under RCU before flushing the pending batch. A non-dying memcg keeps the original lruvec stable against RCU-delayed offlining; a dying memcg redirects the deltas to the first non-dying ancestor.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: f304652609eae3814b0e9d11c75c0e0cb62da31f , < fceb6b7f3ddec6ea9fc11577f4cf1b2da73a3101 (git)
Affected: f304652609eae3814b0e9d11c75c0e0cb62da31f , < de4660898b7aa7e03d3b120a6bfa6b26211e4e77 (git)
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Linux Linux Affected: 7.1
Unaffected: 0 , < 7.1 (semver)
Unaffected: 7.1.8 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/linux/memcontrol.h",
            "mm/vmscan.c"
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                  "vulnerable": true
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: mglru: fix stale batch updates after memcg reparenting\n\nThe mglru page table walker batches per-generation size deltas in\nwalk-\u003enr_pages while walking page tables without holding the lruvec lock. \nThe reset_batch_size() later folds those deltas into walk-\u003elruvec under\nthe lruvec lock.\n\nThe page table walker can run concurrently with the memcg reparenting path\nas follows:\n\nCPU0                           CPU1\n====                           ====\n\nwalk_mm\n--\u003e walk_page_range\n    --\u003e update_batch_size\n        --\u003e walk-\u003enr_pages += delta\n\n                              mem_cgroup_css_offline\n                              --\u003e memcg_reparent_objcgs\n                                  --\u003e lock lruvec\n                                      lru_gen_reparent_memcg\n                                      --\u003e reparent child folios to parent\n                                      unlock lruvec\n\n    lock lruvec\n    reset_batch_size\n    --\u003e child lrugen-\u003enr_pages += delta\n\nThis will trigger the following warning in lru_gen_exit_memcg():\n\n\tVM_WARN_ON_ONCE(memchr_inv(lruvec-\u003elrugen.nr_pages, 0,\n\t\t\t\t   sizeof(lruvec-\u003elrugen.nr_pages)));\n\nAnd the user-visible impact of underestimated nr_pages in MGLRU was\npremature OOMs because MGLRU does not try to reclaim memory when nr_pages\nreaches zero, but there are still more pages.\n\nTo fix it, make reset_batch_size() check CSS_DYING under RCU before\nflushing the pending batch.  A non-dying memcg keeps the original lruvec\nstable against RCU-delayed offlining; a dying memcg redirects the deltas\nto the first non-dying ancestor."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-28T06:53:16.087Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/fceb6b7f3ddec6ea9fc11577f4cf1b2da73a3101"
        },
        {
          "url": "https://git.kernel.org/stable/c/de4660898b7aa7e03d3b120a6bfa6b26211e4e77"
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      ],
      "title": "mm: mglru: fix stale batch updates after memcg reparenting",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80719",
    "datePublished": "2026-08-28T06:53:16.087Z",
    "dateReserved": "2026-08-26T14:34:25.788Z",
    "dateUpdated": "2026-08-28T06:53:16.087Z",
    "state": "PUBLISHED"
  },
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      "date": "2026-09-21",
      "epss": "0.00145",
      "percentile": "0.04112"
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                "product": "Linux",
                "programFiles": [
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                  "mm/vmscan.c"
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                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
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        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: mglru: fix stale batch updates after memcg reparenting\n\nThe mglru page table walker batches per-generation size deltas in\nwalk-\u003enr_pages while walking page tables without holding the lruvec lock. \nThe reset_batch_size() later folds those deltas into walk-\u003elruvec under\nthe lruvec lock.\n\nThe page table walker can run concurrently with the memcg reparenting path\nas follows:\n\nCPU0                           CPU1\n====                           ====\n\nwalk_mm\n--\u003e walk_page_range\n    --\u003e update_batch_size\n        --\u003e walk-\u003enr_pages += delta\n\n                              mem_cgroup_css_offline\n                              --\u003e memcg_reparent_objcgs\n                                  --\u003e lock lruvec\n                                      lru_gen_reparent_memcg\n                                      --\u003e reparent child folios to parent\n                                      unlock lruvec\n\n    lock lruvec\n    reset_batch_size\n    --\u003e child lrugen-\u003enr_pages += delta\n\nThis will trigger the following warning in lru_gen_exit_memcg():\n\n\tVM_WARN_ON_ONCE(memchr_inv(lruvec-\u003elrugen.nr_pages, 0,\n\t\t\t\t   sizeof(lruvec-\u003elrugen.nr_pages)));\n\nAnd the user-visible impact of underestimated nr_pages in MGLRU was\npremature OOMs because MGLRU does not try to reclaim memory when nr_pages\nreaches zero, but there are still more pages.\n\nTo fix it, make reset_batch_size() check CSS_DYING under RCU before\nflushing the pending batch.  A non-dying memcg keeps the original lruvec\nstable against RCU-delayed offlining; a dying memcg redirects the deltas\nto the first non-dying ancestor."
          }
        ],
        "id": "CVE-2026-80719",
        "lastModified": "2026-08-28T08:16:57.720",
        "metrics": {},
        "published": "2026-08-28T08:16:57.720",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/de4660898b7aa7e03d3b120a6bfa6b26211e4e77"
          },
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/fceb6b7f3ddec6ea9fc11577f4cf1b2da73a3101"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-01T11:45:46+00:00",
      "cve": "CVE-2026-80719",
      "id": "CVE-2026-80719",
      "initial_release_date": "2026-08-28T00:00:00+00:00",
      "product_status:known_affected": "14",
      "product_status:known_not_affected": "260",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: mm: mglru: fix stale batch updates after memcg reparenting",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80719.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-01T17:12:32Z",
      "cve": "CVE-2026-80719",
      "id": "CVE-2026-80719",
      "initial_release_date": "2026-08-28T16:33:08Z",
      "product_status:known_not_affected": "353",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-80719",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-80719.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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