GHSA-5XPP-W3QP-6W34

Vulnerability from github – Published: 2026-09-25 12:31 – Updated: 2026-09-25 12:31
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

perf/x86/intel: Prevent drain_pebs() reentry

The PEBS buffer is shared by all events on a CPU, so drain_pebs() must not be reentered. If so, one instance may observe stale buffer state and potentially access out-of-bound memory.

Most invocations happen in NMI context, which naturally prevents reentry. However, drain_pebs() is also reachable from process context via intel_pmu_drain_pebs_buffer().

In those paths, the PMU is often already disabled, but not guaranteed. For example, __intel_pmu_pebs_disable() only disables the target counter, so other active counters can still raise a PMI and interrupt an in-flight drain_pebs(). Here is an example,

__perf_addr_filters_adjust() perf_event_stop() __perf_event_stop() x86_pmu_stop() (event->pmu->stop) intel_pmu_disable_event() intel_pmu_pebs_disable() __intel_pmu_pebs_disable() intel_pmu_drain_large_pebs() intel_pmu_drain_pebs_buffer()

Introduce __intel_pmu_quiesce() and __intel_pmu_resume() helpers and use them in intel_pmu_drain_large_pebs() to disable the full PMU around the intel_pmu_drain_pebs_buffer() call, preventing reentry.

Also add a warning in intel_pmu_drain_pebs_buffer() when the full PMU is not disabled.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-97960"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-25T11:17:23Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf/x86/intel: Prevent drain_pebs() reentry\n\nThe PEBS buffer is shared by all events on a CPU, so drain_pebs() must\nnot be reentered. If so, one instance may observe stale buffer state and\npotentially access out-of-bound memory.\n\nMost invocations happen in NMI context, which naturally prevents reentry.\nHowever, drain_pebs() is also reachable from process context via\nintel_pmu_drain_pebs_buffer().\n\nIn those paths, the PMU is often already disabled, but not guaranteed.\nFor example, __intel_pmu_pebs_disable() only disables the target counter,\nso other active counters can still raise a PMI and interrupt an in-flight\ndrain_pebs(). Here is an example,\n\n__perf_addr_filters_adjust()\n  perf_event_stop()\n    __perf_event_stop()\n      x86_pmu_stop() (event-\u003epmu-\u003estop)\n        intel_pmu_disable_event()\n          intel_pmu_pebs_disable()\n            __intel_pmu_pebs_disable()\n              intel_pmu_drain_large_pebs()\n                intel_pmu_drain_pebs_buffer()\n\nIntroduce __intel_pmu_quiesce() and __intel_pmu_resume() helpers and\nuse them in intel_pmu_drain_large_pebs() to disable the full PMU\naround the intel_pmu_drain_pebs_buffer() call, preventing reentry.\n\nAlso add a warning in intel_pmu_drain_pebs_buffer() when the full PMU is\nnot disabled.",
  "id": "GHSA-5xpp-w3qp-6w34",
  "modified": "2026-09-25T12:31:30Z",
  "published": "2026-09-25T12:31:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-97960"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a56c03a397e2cd0c4cf8da96dcd6214f7d0e7d8c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a5fe19dd8b3ed5fad6e5e0f0c58c7245043ee4af"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c55599c0ec2aa020e41a0599c3044c56d8a2e7d9"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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