ring-buffer: Fix crash passing ERR_PTR to kthread_stop()

{
  "id": "01652ef56d3fea0764781436430dee178498ecb18271afc23a51a7e8b8aeb68c",
  "url": "https://osv.dev/vulnerability/CVE-2026-80730",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ring-buffer: Fix crash passing ERR_PTR to kthread_stop()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Fix crash passing ERR_PTR to kthread_stop() In test_ringbuffer()'s out_free cleanup loop, the check `!rb_threads[cpu]` only catches NULL entries and misses entries that hold an ERR_PTR. rb_threads[] is static, so unassigned slots are NULL. But when kthread_run_on_cpu() fails for a cpu, it stores ERR_PTR(-ENOMEM) (or -EINTR) in rb_threads[cpu] before the creation loop jumps to out_free. That entry is non-NULL, so the old `!ptr` check does not break, and the cleanup proceeds to call kthread_stop() on the ERR_PTR. kthread_stop() then dereferences the bogus pointer, crashing the kernel during the late_initcall self-test. crash logs: BUG: kernel NULL pointer dereference, address: 000000000000001c Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 1 Comm: swapper/0 Not tainted 7.2.0-rc6-dirty #7 PREEMPT(lazy) RIP: 0010:kthread_stop+0x2e/0x220 RBX: fffffffffffffff4 CR2: 000000000000001c Call Trace: test_ringbuffer+0x1ec/0x650 do_one_initcall+0x6c/0x2c0 kernel_init_freeable+0x21d/0x420 kernel_init+0x15/0x1c0 ret_from_fork+0x21b/0x320 Kernel panic - not syncing: Fatal exception",
    "evidence": "osv:CVE-2026-80730",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.183",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.152",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.104",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.45",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.9",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-80730",
      "aliases": [
        "CVE-2026-80730"
      ],
      "affected": [
        {
          "ranges": [
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              "type": "GIT",
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                  "fixed": "51d78fad30dd9ae45721224103662bdbcf210096"
                },
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                  "fixed": "93e7044b548a72022208595d2c1b188bb225ce83"
                },
                {
                  "fixed": "8532983c312e8b875d7c9e440f8ee4674ea4b711"
                },
                {
                  "fixed": "6dd7a06894d6d3dc84319bd0b7d1a7c27df9d902"
                },
                {
                  "fixed": "3ea2fd344d93e3cf9503739b09fd702c0d8f8f0b"
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                {
                  "fixed": "91542863abade2fd4f2b361991f5386ad9d19c8c"
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          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80730.json"
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        {
          "ranges": [
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              "type": "ECOSYSTEM",
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                {
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            {
              "type": "ECOSYSTEM",
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            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "6.19.0"
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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-2026-80730.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:52.648359444Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/3ea2fd344d93e3cf9503739b09fd702c0d8f8f0b",
        "https://git.kernel.org/stable/c/51d78fad30dd9ae45721224103662bdbcf210096",
        "https://git.kernel.org/stable/c/6dd7a06894d6d3dc84319bd0b7d1a7c27df9d902",
        "https://git.kernel.org/stable/c/8532983c312e8b875d7c9e440f8ee4674ea4b711",
        "https://git.kernel.org/stable/c/91542863abade2fd4f2b361991f5386ad9d19c8c",
        "https://git.kernel.org/stable/c/93e7044b548a72022208595d2c1b188bb225ce83",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80730.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-80730",
        "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/2026/80xxx/CVE-2026-80730.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-80730",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 521470,
  "published_at": "2026-09-03T08:21:48.325+00:00"
}