ksmbd: detach blocked lock requests before freeing

{
  "id": "ed38a7e6c212d2ff0b6fadb02367552095a517fd2ce81e32d6b6f41341ca31ee",
  "url": "https://osv.dev/vulnerability/CVE-2026-90155",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ksmbd: detach blocked lock requests before freeing",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ksmbd: detach blocked lock requests before freeing A file_lock retained by ksmbd for byte-range lock bookkeeping can still be part of the VFS blocked-request graph. In particular, the VFS can chain a new waiter below an already blocked request through flc_blocked_requests. The ksmbd_file reference count does not cover that graph. Both __ksmbd_close_fd() and the cross-request unlock path free these retained file_lock objects directly. If a dependent waiter is still attached, locks_release_private() hits BUG_ON(!list_empty(&flc->flc_blocked_requests)). The same lifetime mismatch can leave a freed ksmbd_lock reachable through its request-local llist. Detach the file_lock from the blocked-request graph before freeing it in the close, cross-request unlock, and rollback paths. locks_delete_block() also wakes requests chained below the object. Remove llist when a completed lock is published so a globally visible ksmbd_lock no longer points into the submitting worker's stack.",
    "evidence": "osv:CVE-2026-90155",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.191",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.160",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.114",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.57",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-90155",
      "aliases": [
        "CVE-2026-90155"
      ],
      "affected": [
        {
          "ranges": [
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              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                {
                  "fixed": "4e8b69c06bd6583ec11abef4fae50c2c8d5f3679"
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                {
                  "fixed": "d20d3f6ad8b0b6f4e1bb32cdf7eca251962e8f04"
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                {
                  "fixed": "d31db79cfaa9fce6649772ad279779473ba8aef9"
                },
                {
                  "fixed": "f77d2accafca529e0ea3f979eb6e6cf1dac05c90"
                },
                {
                  "fixed": "514a0b2bc949963497e66cacd433f65dc768a71d"
                },
                {
                  "fixed": "215e8816b1ac25176d911abb8704390413ccee4b"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90155.json"
          }
        },
        {
          "ranges": [
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              "type": "ECOSYSTEM",
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                  "introduced": "5.15.0"
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                  "fixed": "6.1.191"
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              "events": [
                {
                  "introduced": "6.2.0"
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                {
                  "fixed": "6.6.160"
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            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
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                {
                  "fixed": "6.12.114"
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            {
              "type": "ECOSYSTEM",
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                  "introduced": "6.13.0"
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              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
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                {
                  "fixed": "7.2.6"
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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-2026-90155.json"
          }
        }
      ],
      "modified": "2026-11-01T02:30:40.406349996Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/215e8816b1ac25176d911abb8704390413ccee4b",
        "https://git.kernel.org/stable/c/4e8b69c06bd6583ec11abef4fae50c2c8d5f3679",
        "https://git.kernel.org/stable/c/514a0b2bc949963497e66cacd433f65dc768a71d",
        "https://git.kernel.org/stable/c/d20d3f6ad8b0b6f4e1bb32cdf7eca251962e8f04",
        "https://git.kernel.org/stable/c/d31db79cfaa9fce6649772ad279779473ba8aef9",
        "https://git.kernel.org/stable/c/f77d2accafca529e0ea3f979eb6e6cf1dac05c90",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90155.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-90155",
        "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/2026/90xxx/CVE-2026-90155.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-90155",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 516750,
  "published_at": "2026-09-17T16:06:47.716+00:00"
}