samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify

{
  "id": "fdd450294f36acfbc117dd875bcfcc663ffbcff492bda8913c9af847a571efd9",
  "url": "https://osv.dev/vulnerability/CVE-2026-90066",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify ftrace_direct_multi_init() assigns kthread_run()'s return value to simple_tsk without an IS_ERR() check. When kthread_run() fails it returns ERR_PTR(-ENOMEM), but init still returns 0, so the module loads with simple_tsk holding an error pointer. On unload, ftrace_direct_multi_exit() then passes that ERR_PTR to kthread_stop(), leading to a null-pointer-dereference. Check the return value of kthread_run() with IS_ERR(); on failure, unregister the ftrace direct call and propagate the error code.",
    "evidence": "osv:CVE-2026-90066",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.191",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.157",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.110",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.52",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-90066",
      "aliases": [
        "CVE-2026-90066"
      ],
      "affected": [
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              "type": "GIT",
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                  "fixed": "98b7b2a29ae87937aa02ab9391543ef8c602cd94"
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                {
                  "fixed": "626614df9080d7052fbe24dc90b5434717ab7a9f"
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                {
                  "fixed": "cf839636911d8313f3ecd098329fd0b96499e4cf"
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                  "fixed": "6727b7618f49401acf373fa3ec5712e2ec52e5cf"
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90066.json"
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                  "introduced": "6.19.0"
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                  "fixed": "7.2.6"
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90066.json"
          }
        }
      ],
      "modified": "2026-11-01T02:30:38.941675460Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/02866f063062dcc5686445c738be003de9787250",
        "https://git.kernel.org/stable/c/626614df9080d7052fbe24dc90b5434717ab7a9f",
        "https://git.kernel.org/stable/c/6727b7618f49401acf373fa3ec5712e2ec52e5cf",
        "https://git.kernel.org/stable/c/7a96b9f6d5ba23dbce66c8a4a242effd4c01a830",
        "https://git.kernel.org/stable/c/98b7b2a29ae87937aa02ab9391543ef8c602cd94",
        "https://git.kernel.org/stable/c/cf839636911d8313f3ecd098329fd0b96499e4cf",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90066.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-90066",
        "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-2026-90066.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-90066",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 488357,
  "published_at": "2026-09-17T16:05:48.921+00:00"
}