s390/pai: Handle multiple PMU stop callback invocations

{
  "id": "9a392fcca8bcf0a44af46e05646d807f64ca0849d73bd16c19cd2423db15ec17",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-99125",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "s390/pai: Handle multiple PMU stop callback invocations",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: s390/pai: Handle multiple PMU stop callback invocations Handle the following scenario: The kernel protects itself against a very high sampling load and throttles the sampling using: perf_event_throttle() --> PMU->stop() Shortly later the scheduler may terminate the task and removes it from the CPU. It again calls PMU->stop() which results in two invocations of PMU->stop() called back to back. Protect against this and check the PERF_HES_STOPPED bit on function entry. If it is already set return. Clear bit PERF_HES_STOPPED in PMU->start(). Prohibit ioctl(fd, PERF_EVENT_IOC_PERIOD, ...) call for this event. It sets perf_event::event_limit to a positive value and causes perf_event_overflow() to invoke pai_stop() call back function when perf_event::event_limit hits zero. This is not supported because the sample events CRYPTO_ALL and NNPA_ALL are only taken at schedule out of a task. Use list_for_each_entry_safe() for safe iteration over syswide_list in pai_have_samples().",
    "evidence": "cve:CVE-2026-99125",
    "products": [
      {
        "name": {
          "value": "Linux",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      },
      {
        "name": {
          "value": "Linux",
          "evidence": "/containers/cna/affected/1/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-99125",
      "aliases": [
        "CVE-2026-99125"
      ],
      "metrics": [],
      "affected": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "9f66572f2889a5e72a9d7e17787e52f03b1f7bd8",
              "lessThan": "cf348ec613f75b9774291e47b804fd7010835a6c",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9f66572f2889a5e72a9d7e17787e52f03b1f7bd8",
              "lessThan": "f3110e969ad226ffbb2d9b4bf5387e68d0d9ef40",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "arch/s390/kernel/perf_pai.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.11",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "7.2.13",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "arch/s390/kernel/perf_pai.c"
          ],
          "defaultStatus": "affected"
        }
      ],
      "modified": "2026-10-28T10:34:40.025Z",
      "provider": "cve",
      "references": [
        "https://git.kernel.org/stable/c/cf348ec613f75b9774291e47b804fd7010835a6c",
        "https://git.kernel.org/stable/c/f3110e969ad226ffbb2d9b4bf5387e68d0d9ef40"
      ],
      "provider_metadata": {
        "cna": {
          "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
          "shortName": "Linux",
          "dateUpdated": "2026-10-28T10:34:40.025Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-99125",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-cve",
  "document_id": 425351,
  "published_at": "2026-10-28T10:34:40.025+00:00"
}