{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2025-37878",
  "modified": "2026-10-07T14:35:31Z",
  "upstream": [
    "CVE-2025-37878"
  ],
  "published": "2025-05-09T06:46:36Z",
  "summary": "perf/core: Fix WARN_ON(!ctx) in __free_event() for partial init",
  "details": "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->ctx assignment to\noccur immediately after the child event is allocated. Ensure that\nchild_event->ctx 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's 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->ctx 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->ctx was assigned, violating its\nprecondition. The solution is to assign child_event->ctx 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->ctx assignment\ndirectly after child_event->pmu_ctx is set but before checking if the\nparent event is orphaned. The cleanup routine depends on\nevent->pmu_ctx being non-NULL before it verifies event->ctx is\nnon-NULL. This also maintains the author's 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. ]",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.12.25-1+rpt1"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-2712",
            "binary_version": "1:6.12.25-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-v6",
            "binary_version": "1:6.12.25-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-v7",
            "binary_version": "1:6.12.25-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-v7l",
            "binary_version": "1:6.12.25-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-v8",
            "binary_version": "1:6.12.25-1+rpt1"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.12.25-1+rpt1": {
            "linux_commit": "3dd2c2c507c271d411fab2e82a2b3b7e0b6d3f16",
            "upstream_version": "6.12.25",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.12.26"
          }
        }
      }
    },
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:13",
        "name": "linux"
      },
      "versions": [
        "1:6.12.25-1+rpt1+trixie"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-2712",
            "binary_version": "1:6.12.25-1+rpt1+trixie"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-v6",
            "binary_version": "1:6.12.25-1+rpt1+trixie"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-v7",
            "binary_version": "1:6.12.25-1+rpt1+trixie"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-v8",
            "binary_version": "1:6.12.25-1+rpt1+trixie"
          },
          {
            "binary_name": "linux-image-6.12.25+rpt-rpi-v8-rt",
            "binary_version": "1:6.12.25-1+rpt1+trixie"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.12.25-1+rpt1+trixie": {
            "linux_commit": "3dd2c2c507c271d411fab2e82a2b3b7e0b6d3f16",
            "upstream_version": "6.12.25",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.12.26"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-37878"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/90dc6c1e3b200812da8d0aa030e1b7fda8226d0e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/cb56cd11feabf99e08bc18960700a53322ffcea7"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/0ba3a4ab76fd3367b9cb680cad70182c896c795c"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-05-24T06:48:58Z"
  }
}