CVE-2026-90155 (GCVE-0-2026-90155)
Vulnerability from cvelistv5
Published
2026-09-17 16:06
Modified
2026-10-30 12:34
Severity ?
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: d63528eb0d43c4796c42aad56889dec12cf4e122
Version: d63528eb0d43c4796c42aad56889dec12cf4e122
Version: d63528eb0d43c4796c42aad56889dec12cf4e122
Version: d63528eb0d43c4796c42aad56889dec12cf4e122
Version: d63528eb0d43c4796c42aad56889dec12cf4e122
Version: d63528eb0d43c4796c42aad56889dec12cf4e122
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{
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      "cpeApplicability": [
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: detach blocked lock requests before freeing\n\nA file_lock retained by ksmbd for byte-range lock bookkeeping can still\nbe part of the VFS blocked-request graph. In particular, the VFS can\nchain a new waiter below an already blocked request through\nflc_blocked_requests. The ksmbd_file reference count does not cover that\ngraph.\n\nBoth __ksmbd_close_fd() and the cross-request unlock path free these\nretained file_lock objects directly. If a dependent waiter is still\nattached, locks_release_private() hits\nBUG_ON(!list_empty(\u0026flc-\u003eflc_blocked_requests)). The same lifetime\nmismatch can leave a freed ksmbd_lock reachable through its request-local\nllist.\n\nDetach the file_lock from the blocked-request graph before freeing it in\nthe close, cross-request unlock, and rollback paths. locks_delete_block()\nalso wakes requests chained below the object. Remove llist when a\ncompleted lock is published so a globally visible ksmbd_lock no longer\npoints into the submitting worker\u0027s stack."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-30T12:34:28.100Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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      "references": [
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          "url": "https://git.kernel.org/stable/c/4e8b69c06bd6583ec11abef4fae50c2c8d5f3679"
        },
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          "url": "https://git.kernel.org/stable/c/d20d3f6ad8b0b6f4e1bb32cdf7eca251962e8f04"
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          "url": "https://git.kernel.org/stable/c/d31db79cfaa9fce6649772ad279779473ba8aef9"
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          "url": "https://git.kernel.org/stable/c/514a0b2bc949963497e66cacd433f65dc768a71d"
        },
        {
          "url": "https://git.kernel.org/stable/c/215e8816b1ac25176d911abb8704390413ccee4b"
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      ],
      "title": "ksmbd: detach blocked lock requests before freeing",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90155",
    "datePublished": "2026-09-17T16:06:47.716Z",
    "dateReserved": "2026-09-11T19:38:34.790Z",
    "dateUpdated": "2026-10-30T12:34:28.100Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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