github - ghsa-px83-f67g-j9g9

GHSA-PX83-F67G-J9G9

Vulnerability from github – Published: 2025-12-09 18:30 – Updated: 2025-12-09 18:30

Details

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

perf/core: Fix system hang caused by cpu-clock usage

cpu-clock usage by the async-profiler tool can trigger a system hang, which got bisected back to the following commit by Octavia Togami:

18dbcbfabfff ("perf: Fix the POLL_HUP delivery breakage") causes this issue

The root cause of the hang is that cpu-clock is a special type of SW event which relies on hrtimers. The __perf_event_overflow() callback is invoked from the hrtimer handler for cpu-clock events, and __perf_event_overflow() tries to call cpu_clock_event_stop() to stop the event, which calls htimer_cancel() to cancel the hrtimer.

But that's a recursion into the hrtimer code from a hrtimer handler, which (unsurprisingly) deadlocks.

To fix this bug, use hrtimer_try_to_cancel() instead, and set the PERF_HES_STOPPED flag, which causes perf_swevent_hrtimer() to stop the event once it sees the PERF_HES_STOPPED flag.

[ mingo: Fixed the comments and improved the changelog. ]

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{
  "affected": [],
  "aliases": [
    "CVE-2025-40327"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-09T16:17:42Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf/core: Fix system hang caused by cpu-clock usage\n\ncpu-clock usage by the async-profiler tool can trigger a system hang,\nwhich got bisected back to the following commit by Octavia Togami:\n\n  18dbcbfabfff (\"perf: Fix the POLL_HUP delivery breakage\") causes this issue\n\nThe root cause of the hang is that cpu-clock is a special type of SW\nevent which relies on hrtimers. The __perf_event_overflow() callback\nis invoked from the hrtimer handler for cpu-clock events, and\n__perf_event_overflow() tries to call cpu_clock_event_stop()\nto stop the event, which calls htimer_cancel() to cancel the hrtimer.\n\nBut that\u0027s a recursion into the hrtimer code from a hrtimer handler,\nwhich (unsurprisingly) deadlocks.\n\nTo fix this bug, use hrtimer_try_to_cancel() instead, and set\nthe PERF_HES_STOPPED flag, which causes perf_swevent_hrtimer()\nto stop the event once it sees the PERF_HES_STOPPED flag.\n\n[ mingo: Fixed the comments and improved the changelog. ]",
  "id": "GHSA-px83-f67g-j9g9",
  "modified": "2025-12-09T18:30:35Z",
  "published": "2025-12-09T18:30:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-40327"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6b8c512811644cf2f5eaf6f44e928683c54127f0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eb3182ef0405ff2f6668fd3e5ff9883f60ce8801"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2025-40327 (GCVE-0-2025-40327)

Vulnerability from cvelistv5 – Published: 2025-12-09 04:09 – Updated: 2025-12-09 04:09

Summary

In the Linux kernel, the following vulnerability has been resolved: perf/core: Fix system hang caused by cpu-clock usage cpu-clock usage by the async-profiler tool can trigger a system hang, which got bisected back to the following commit by Octavia Togami: 18dbcbfabfff ("perf: Fix the POLL_HUP delivery breakage") causes this issue The root cause of the hang is that cpu-clock is a special type of SW event which relies on hrtimers. The __perf_event_overflow() callback is invoked from the hrtimer handler for cpu-clock events, and __perf_event_overflow() tries to call cpu_clock_event_stop() to stop the event, which calls htimer_cancel() to cancel the hrtimer. But that's a recursion into the hrtimer code from a hrtimer handler, which (unsurprisingly) deadlocks. To fix this bug, use hrtimer_try_to_cancel() instead, and set the PERF_HES_STOPPED flag, which causes perf_swevent_hrtimer() to stop the event once it sees the PERF_HES_STOPPED flag. [ mingo: Fixed the comments and improved the changelog. ]

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/6b8c512811644cf2f…
	https://git.kernel.org/stable/c/eb3182ef0405ff2f6…

Impacted products

Vendor

Product

Version

Linux

Affected: 18dbcbfabfffc4a5d3ea10290c5ad27f22b0d240 , < 6b8c512811644cf2f5eaf6f44e928683c54127f0 (git)
Affected: 18dbcbfabfffc4a5d3ea10290c5ad27f22b0d240 , < eb3182ef0405ff2f6668fd3e5ff9883f60ce8801 (git)
Affected: b2de0c9ce8e542b5cb4cd3944620d9dd1ea1f0ac (git)

Linux

Affected: 6.17
Unaffected: 0 , < 6.17 (semver)
Unaffected: 6.17.8 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/events/core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "18dbcbfabfffc4a5d3ea10290c5ad27f22b0d240",
              "versionType": "git"
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              "lessThan": "eb3182ef0405ff2f6668fd3e5ff9883f60ce8801",
              "status": "affected",
              "version": "18dbcbfabfffc4a5d3ea10290c5ad27f22b0d240",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b2de0c9ce8e542b5cb4cd3944620d9dd1ea1f0ac",
              "versionType": "git"
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          ]
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          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/events/core.c"
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          "versions": [
            {
              "status": "affected",
              "version": "6.17"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "version": "6.17.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.17.8",
                  "versionStartIncluding": "6.17",
                  "vulnerable": true
                },
                {
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                  "vulnerable": true
                },
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
                }
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              "negate": false,
              "operator": "OR"
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          ]
        }
      ],
      "descriptions": [
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf/core: Fix system hang caused by cpu-clock usage\n\ncpu-clock usage by the async-profiler tool can trigger a system hang,\nwhich got bisected back to the following commit by Octavia Togami:\n\n  18dbcbfabfff (\"perf: Fix the POLL_HUP delivery breakage\") causes this issue\n\nThe root cause of the hang is that cpu-clock is a special type of SW\nevent which relies on hrtimers. The __perf_event_overflow() callback\nis invoked from the hrtimer handler for cpu-clock events, and\n__perf_event_overflow() tries to call cpu_clock_event_stop()\nto stop the event, which calls htimer_cancel() to cancel the hrtimer.\n\nBut that\u0027s a recursion into the hrtimer code from a hrtimer handler,\nwhich (unsurprisingly) deadlocks.\n\nTo fix this bug, use hrtimer_try_to_cancel() instead, and set\nthe PERF_HES_STOPPED flag, which causes perf_swevent_hrtimer()\nto stop the event once it sees the PERF_HES_STOPPED flag.\n\n[ mingo: Fixed the comments and improved the changelog. ]"
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      "providerMetadata": {
        "dateUpdated": "2025-12-09T04:09:43.522Z",
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        "shortName": "Linux"
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      "title": "perf/core: Fix system hang caused by cpu-clock usage",
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    "datePublished": "2025-12-09T04:09:43.522Z",
    "dateReserved": "2025-04-16T07:20:57.186Z",
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}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-PX83-F67G-J9G9

CVE-2025-40327 (GCVE-0-2025-40327)

Tags

Sightings

Nomenclature