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blk-cgroup: fix race between policy activation and blkg destruction

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: fix race between policy activation and blkg destruction When switching an IO scheduler on a block device, blkcg_activate_policy() allocates blkg_policy_data (pd) for all blkgs attached to the queue. However, blkcg_activate_policy() may race with concurrent blkcg deletion, leading to use-after-free and memory leak issues. The use-after-free occurs in the following race: T1 (blkcg_activate_policy): - Successfully allocates pd for blkg1 (loop0->queue, blkcgA) - Fails to allocate pd for blkg2 (loop0->queue, blkcgB) - Enters the enomem rollback path to release blkg1 resources T2 (blkcg deletion): - blkcgA is deleted concurrently - blkg1 is freed via blkg_free_workfn() - blkg1->pd is freed T1 (continued): - Rollback path accesses blkg1->pd->online after pd is freed - Triggers use-after-free In addition, blkg_free_workfn() frees pd before removing the blkg from q->blkg_list. This allows blkcg_activate_policy() to allocate a new pd for a blkg that is being destroyed, leaving the newly allocated pd unreachable when the blkg is finally freed. Fix these races by extending blkcg_mutex coverage to serialize blkcg_activate_policy() rollback and blkg destruction, ensuring pd lifecycle is synchronized with blkg list visibility.

Announced Source revision 1
Original source ↗

CVE-2026-90326

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-90326

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
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        "status": "affected",
        "version": "81c1188905f88b77743d1fdeeedfc8cb7b67787d",
        "lessThan": "b5dae1cd0d8368b4338430ff93403df67f0b8bcc",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "bfe46d2efe46c5c952f982e2ca94fe2ec5e58e2a",
        "lessThan": "083b58373463a6e5ee60ecb135269348f68ad7df",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f1c006f1c6850c14040f8337753a63119bba39b9",
        "lessThan": "17c18a0df70c2b89ff7fcd74622f1540e98d00fd",
        "versionType": "git"
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        "versionType": "git"
      },
      {
        "status": "affected",
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        "lessThan": "2cf9f50a38c1839e549a08e22aa35e8d69e2c8fd",
        "versionType": "git"
      },
      {
        "status": "affected",
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        "lessThan": "5313d4d41739b0cb63000747c97bb1217ac45f3e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "6.1.16",
        "lessThan": "6.1.17",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.2.3",
        "lessThan": "6.2.4",
        "versionType": "semver"
      }
    ],
    "programFiles": [
      "block/blk-cgroup.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.3"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.3",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.1.17",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.2.4",
        "versionType": "semver",
        "lessThanOrEqual": "6.2.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.160",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.114",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.52",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.6",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "block/blk-cgroup.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-90326

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#48662 · Revision 1
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