CVE-2025-37878 (GCVE-0-2025-37878)

Vulnerability from cvelistv5 – Published: 2025-05-09 06:45 – Updated: 2026-01-02 15:29
VLAI?
Title
perf/core: Fix WARN_ON(!ctx) in __free_event() for partial init
Summary
In the Linux kernel, the following vulnerability has been resolved: perf/core: Fix WARN_ON(!ctx) in __free_event() for partial init Move the get_ctx(child_ctx) call and the child_event->ctx assignment to occur immediately after the child event is allocated. Ensure that child_event->ctx is non-NULL before any subsequent error path within inherit_event calls free_event(), satisfying the assumptions of the cleanup code. Details: There's no clear Fixes tag, because this bug is a side-effect of multiple interacting commits over time (up to 15 years old), not a single regression. The code initially incremented refcount then assigned context immediately after the child_event was created. Later, an early validity check for child_event was added before the refcount/assignment. Even later, a WARN_ON_ONCE() cleanup check was added, assuming event->ctx is valid if the pmu_ctx is valid. The problem is that the WARN_ON_ONCE() could trigger after the initial check passed but before child_event->ctx was assigned, violating its precondition. The solution is to assign child_event->ctx right after its initial validation. This ensures the context exists for any subsequent checks or cleanup routines, resolving the WARN_ON_ONCE(). To resolve it, defer the refcount update and child_event->ctx assignment directly after child_event->pmu_ctx is set but before checking if the parent event is orphaned. The cleanup routine depends on event->pmu_ctx being non-NULL before it verifies event->ctx is non-NULL. This also maintains the author's original intent of passing in child_ctx to find_get_pmu_context before its refcount/assignment. [ mingo: Expanded the changelog from another email by Gabriel Shahrouzi. ]
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 7ef5aa081f989ecfecc1df02068a80aebbd3ec31 , < 90dc6c1e3b200812da8d0aa030e1b7fda8226d0e (git)
Affected: 1209b0b29fd472e7dbd2b06544b019dd9f9b7e51 , < cb56cd11feabf99e08bc18960700a53322ffcea7 (git)
Affected: c70ca298036c58a88686ff388d3d367e9d21acf0 , < 0ba3a4ab76fd3367b9cb680cad70182c896c795c (git)
Affected: 315a50c6b1c6ce191f19f3372935d8e2ed9b53a6 (git)
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    Linux Linux Affected: 6.12.24 , < 6.12.26 (semver)
Affected: 6.14.3 , < 6.14.5 (semver)
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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": [
            {
              "lessThan": "90dc6c1e3b200812da8d0aa030e1b7fda8226d0e",
              "status": "affected",
              "version": "7ef5aa081f989ecfecc1df02068a80aebbd3ec31",
              "versionType": "git"
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6.12.26",
              "status": "affected",
              "version": "6.12.24",
              "versionType": "semver"
            },
            {
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              "status": "affected",
              "version": "6.14.3",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.26",
                  "versionStartIncluding": "6.12.24",
                  "vulnerable": true
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                {
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                  "versionStartIncluding": "6.14.3",
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                  "vulnerable": true
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf/core: Fix WARN_ON(!ctx) in __free_event() for partial init\n\nMove the get_ctx(child_ctx) call and the child_event-\u003ectx assignment to\noccur immediately after the child event is allocated. Ensure that\nchild_event-\u003ectx is non-NULL before any subsequent error path within\ninherit_event calls free_event(), satisfying the assumptions of the\ncleanup code.\n\nDetails:\n\nThere\u0027s no clear Fixes tag, because this bug is a side-effect of\nmultiple interacting commits over time (up to 15 years old), not\na single regression.\n\nThe code initially incremented refcount then assigned context\nimmediately after the child_event was created. Later, an early\nvalidity check for child_event was added before the\nrefcount/assignment. Even later, a WARN_ON_ONCE() cleanup check was\nadded, assuming event-\u003ectx is valid if the pmu_ctx is valid.\nThe problem is that the WARN_ON_ONCE() could trigger after the initial\ncheck passed but before child_event-\u003ectx was assigned, violating its\nprecondition. The solution is to assign child_event-\u003ectx right after\nits initial validation. This ensures the context exists for any\nsubsequent checks or cleanup routines, resolving the WARN_ON_ONCE().\n\nTo resolve it, defer the refcount update and child_event-\u003ectx assignment\ndirectly after child_event-\u003epmu_ctx is set but before checking if the\nparent event is orphaned. The cleanup routine depends on\nevent-\u003epmu_ctx being non-NULL before it verifies event-\u003ectx is\nnon-NULL. This also maintains the author\u0027s original intent of passing\nin child_ctx to find_get_pmu_context before its refcount/assignment.\n\n[ mingo: Expanded the changelog from another email by Gabriel Shahrouzi. ]"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-01-02T15:29:25.085Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/90dc6c1e3b200812da8d0aa030e1b7fda8226d0e"
        },
        {
          "url": "https://git.kernel.org/stable/c/cb56cd11feabf99e08bc18960700a53322ffcea7"
        },
        {
          "url": "https://git.kernel.org/stable/c/0ba3a4ab76fd3367b9cb680cad70182c896c795c"
        }
      ],
      "title": "perf/core: Fix WARN_ON(!ctx) in __free_event() for partial init",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-37878",
    "datePublished": "2025-05-09T06:45:42.459Z",
    "dateReserved": "2025-04-16T04:51:23.960Z",
    "dateUpdated": "2026-01-02T15:29:25.085Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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