tracing: Undo the registration when enabling the histogram trigger fails

{
  "id": "83ca0011cf1b2f9792d15b4357b9521282f71a335b531ff5147b5329af65faf5",
  "url": "https://osv.dev/vulnerability/CVE-2026-97918",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "tracing: Undo the registration when enabling the histogram trigger fails",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: tracing: Undo the registration when enabling the histogram trigger fails Commit 6f86bdeab633 (\"tracing: Fix bad hist from corrupting named_triggers list\") described how a trigger that is registered but not on file->triggers ends up freed while still on the global named_triggers list, and moved the registration down so that hist_trigger_enable() follows it immediately. One path still gets there. hist_trigger_enable() adds the trigger and takes it straight back out when the event cannot be enabled: list_add_tail_rcu(&data->list, &file->triggers); update_cond_flag(file); if (trace_event_trigger_enable_disable(file, 1) < 0) { list_del_rcu(&data->list); update_cond_flag(file); ret--; } so the list walk in hist_unregister_trigger() matches nothing, test stays NULL, and the ->free() that would call del_named_trigger() is skipped. out_unreg falls through to out_free, which frees the trigger anyway: BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0 Read of size 8 at addr ffff8880091d3160 by task init/1 find_named_trigger+0xac/0xc0 hist_register_trigger+0xc1/0xa00 event_hist_trigger_parse+0x3146/0x6af0 event_trigger_write+0xce/0x160 Freed by task 69: kfree+0x154/0x420 trigger_kthread_fn+0xfd/0x160 Leave the trigger where hist_unregister_trigger() can find it and let that undo the registration, which is the only code that knows all of what cmd_ops->init() took: the named list entry, the hist_pad reference,",
    "evidence": "osv:CVE-2026-97918",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.6.160",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.112",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.53",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.7",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-97918",
      "aliases": [
        "CVE-2026-97918"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "067fe038e70f6e64960d26a79c4df5f1413d0f13"
                },
                {
                  "fixed": "880712b6f48103ba3a04b154ff076d45fe86dcec"
                },
                {
                  "fixed": "c7ee2d5733574d4694f7c0035e4381f54c1fca27"
                },
                {
                  "fixed": "51b07104d563d4be2be34158d3b9d922ca417642"
                },
                {
                  "fixed": "bfa6bc11aef93a3d9db0ac9564b734849a9d959b"
                },
                {
                  "fixed": "92383cef66791a0c63a2f27755cadbdb2fbf270b"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97918.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.17.0"
                },
                {
                  "fixed": "6.6.160"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
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                {
                  "fixed": "6.12.112"
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              ]
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            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.53"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.7"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97918.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:23.351062433Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/51b07104d563d4be2be34158d3b9d922ca417642",
        "https://git.kernel.org/stable/c/880712b6f48103ba3a04b154ff076d45fe86dcec",
        "https://git.kernel.org/stable/c/92383cef66791a0c63a2f27755cadbdb2fbf270b",
        "https://git.kernel.org/stable/c/bfa6bc11aef93a3d9db0ac9564b734849a9d959b",
        "https://git.kernel.org/stable/c/c7ee2d5733574d4694f7c0035e4381f54c1fca27",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97918.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-97918",
        "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/2026/97xxx/CVE-2026-97918.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-97918",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 489776,
  "published_at": "2026-09-25T10:22:39.162+00:00"
}