dm cache: fix null-deref with concurrent writes in passthrough mode

{
  "id": "1f2e1877da438c355faaa4fba955aa60468c4827c54cb7110550654dbaf71e86",
  "url": "https://osv.dev/vulnerability/CVE-2026-53064",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "dm cache: fix null-deref with concurrent writes in passthrough mode",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: dm cache: fix null-deref with concurrent writes in passthrough mode In passthrough mode, when dm-cache starts to invalidate a cache entry and bio prison cell lock fails due to concurrent write to the same cached block, mg->cell remains NULL. The error path in invalidate_complete() attempts to unlock and free the cell unconditionally, causing a NULL pointer dereference: KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 UID: 0 PID: 134 Comm: fio Not tainted 6.19.0-rc7 #3 PREEMPT RIP: 0010:dm_cell_unlock_v2+0x3f/0x210 Call Trace: invalidate_complete+0xef/0x430 map_bio+0x130f/0x1a10 cache_map+0x320/0x6b0 __map_bio+0x458/0x510 dm_submit_bio+0x40e/0x16d0 __submit_bio+0x419/0x870 Reproduce steps: 1. Create a cache device dmsetup create cmeta --table \"0 8192 linear /dev/sdc 0\" dmsetup create cdata --table \"0 131072 linear /dev/sdc 8192\" dmsetup create corig --table \"0 262144 linear /dev/sdc 262144\" dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct dmsetup create cache --table \"0 262144 cache /dev/mapper/cmeta \\ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0\" 2. Promote the first data block into cache fio --filename=/dev/mapper/cache --name=populate --rw=write --bs=4k \\ --direct=1 --size=64k 3. Reload the cache into passthrough mode dmsetup suspend cache dmsetup reload cache --table \"0 262144 cache /dev/mapper/cmeta \\ /dev/mapper/cdata /dev/mapper/corig",
    "evidence": "osv:CVE-2026-53064",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.258",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.209",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.175",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.141",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.91",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.33",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.0.10",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-53064",
      "aliases": [
        "CVE-2026-53064"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                {
                  "fixed": "ee38fb00e1a80f46a4990e38f25ecb04ae7b7417"
                },
                {
                  "fixed": "c7fb6bc864c4910b344dafa36dd5028e9b980768"
                },
                {
                  "fixed": "0aa745fea1f8dc81bcdd0a45e215b6706727b482"
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53064.json"
          }
        },
        {
          "ranges": [
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              "type": "ECOSYSTEM",
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                  "introduced": "4.12.0"
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                {
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53064.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:28.062788671Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/01264a6a3a3ad7ac1d73443299cd5a9568002454",
        "https://git.kernel.org/stable/c/0aa745fea1f8dc81bcdd0a45e215b6706727b482",
        "https://git.kernel.org/stable/c/25dcc1989c194ba2b5fb6d03cbb9b83814ac0d15",
        "https://git.kernel.org/stable/c/7d1f98d668ee34c1d15bdc0420fdd062f24a27c0",
        "https://git.kernel.org/stable/c/a2635d541a93fd111e743cf14b6275dc81be2abc",
        "https://git.kernel.org/stable/c/c7fb6bc864c4910b344dafa36dd5028e9b980768",
        "https://git.kernel.org/stable/c/df3b8ef06cc62de4fca5d2108e285085b3cffd44",
        "https://git.kernel.org/stable/c/ee38fb00e1a80f46a4990e38f25ecb04ae7b7417",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53064.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-53064",
        "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/2026/53xxx/CVE-2026-53064.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-53064",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 494565,
  "published_at": "2026-06-24T16:30:07.536+00:00"
}