devlink: rate: Unset parent pointer in devl_rate_nodes_destroy

{
  "id": "b7f72def44652a609eb50a75bba8888f2a4ffd6ace4dbaeae0cf27bc480468ea",
  "url": "https://osv.dev/vulnerability/CVE-2025-40251",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "devlink: rate: Unset parent pointer in devl_rate_nodes_destroy",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: devlink: rate: Unset parent pointer in devl_rate_nodes_destroy The function devl_rate_nodes_destroy is documented to \"Unset parent for all rate objects\". However, it was only calling the driver-specific `rate_leaf_parent_set` or `rate_node_parent_set` ops and decrementing the parent's refcount, without actually setting the `devlink_rate->parent` pointer to NULL. This leaves a dangling pointer in the `devlink_rate` struct, which cause refcount error in netdevsim[1] and mlx5[2]. In addition, this is inconsistent with the behavior of `devlink_nl_rate_parent_node_set`, where the parent pointer is correctly cleared. This patch fixes the issue by explicitly setting `devlink_rate->parent` to NULL after notifying the driver, thus fulfilling the function's documented behavior for all rate objects. [1] repro steps: echo 1 > /sys/bus/netdevsim/new_device devlink dev eswitch set netdevsim/netdevsim1 mode switchdev echo 1 > /sys/bus/netdevsim/devices/netdevsim1/sriov_numvfs devlink port function rate add netdevsim/netdevsim1/test_node devlink port function rate set netdevsim/netdevsim1/128 parent test_node echo 1 > /sys/bus/netdevsim/del_device dmesg: refcount_t: decrement hit 0; leaking memory. WARNING: CPU: 8 PID: 1530 at lib/refcount.c:31 refcount_warn_saturate+0x42/0xe0 CPU: 8 UID: 0 PID: 1530 Comm: bash Not tainted 6.18.0-rc4+ #1 NONE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552ce722",
    "evidence": "osv:CVE-2025-40251",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
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            "evidence": "/affected/1/ranges"
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            "value": "6.6.118",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.60",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.17.10",
            "evidence": "/affected/1/ranges"
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    "severity": "high",
    "structured": {
      "id": "CVE-2025-40251",
      "aliases": [
        "CVE-2025-40251"
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      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
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          "database_specific": {
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      ],
      "modified": "2026-10-28T02:30:34.460487013Z",
      "provider": "osv",
      "references": [
        "https://cert-portal.siemens.com/productcert/html/ssa-253495.html",
        "https://git.kernel.org/stable/c/542f45486f1ce2d2dde75bd85aca0389ef7046c3",
        "https://git.kernel.org/stable/c/715d9cda646a8a38ea8b2bb5afb679a7464055e2",
        "https://git.kernel.org/stable/c/90e51e20bcec9bff5b2421ce1bd95704764655f5",
        "https://git.kernel.org/stable/c/c70df6c17d389cc743f0eb30160e2d6bc6910db8",
        "https://git.kernel.org/stable/c/f94c1a114ac209977bdf5ca841b98424295ab1f0",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40251.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-40251",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40251.json"
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        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
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  "source_id": "core-osv",
  "document_id": 501988,
  "published_at": "2025-12-04T16:08:13.71+00:00"
}