gpio: aggregator: protect driver attr handlers against module unload

{
  "id": "be52829b1a79ea95b1eb8240e67c561d20b2020f3b3fbe7ad0c844185ab7c92e",
  "url": "https://osv.dev/vulnerability/CVE-2025-21943",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "gpio: aggregator: protect driver attr handlers against module unload",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: gpio: aggregator: protect driver attr handlers against module unload Both new_device_store and delete_device_store touch module global resources (e.g. gpio_aggregator_lock). To prevent race conditions with module unload, a reference needs to be held. Add try_module_get() in these handlers. For new_device_store, this eliminates what appears to be the most dangerous scenario: if an id is allocated from gpio_aggregator_idr but platform_device_register has not yet been called or completed, a concurrent module unload could fail to unregister/delete the device, leaving behind a dangling platform device/GPIO forwarder. This can result in various issues. The following simple reproducer demonstrates these problems: #!/bin/bash while :; do # note: whether 'gpiochip0 0' exists or not does not matter. echo 'gpiochip0 0' > /sys/bus/platform/drivers/gpio-aggregator/new_device done & while :; do modprobe gpio-aggregator modprobe -r gpio-aggregator done & wait Starting with the following warning, several kinds of warnings will appear and the system may become unstable: ------------[ cut here ]------------ list_del corruption, ffff888103e2e980->next is LIST_POISON1 (dead000000000100) WARNING: CPU: 1 PID: 1327 at lib/list_debug.c:56 __list_del_entry_valid_or_report+0xa3/0x120 [...] RIP: 0010:__list_del_entry_valid_or_report+0xa3/0x120 [...] Call Trace: ? __list_del_entry_valid_or_report+0xa3/0x120 ? __warn.cold+0x93/0xf2 ? __l",
    "evidence": "osv:CVE-2025-21943",
    "products": [
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    "severity": "medium",
    "structured": {
      "id": "CVE-2025-21943",
      "aliases": [
        "CVE-2025-21943"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
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      "modified": "2026-10-28T02:30:42.081159597Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/12f65d1203507f7db3ba59930fe29a3b8eee9945",
        "https://git.kernel.org/stable/c/56281a76b805b5ac61feb5d580139695a22f87f0",
        "https://git.kernel.org/stable/c/807789018186cf508ceb3a1f8f02935cd195717b",
        "https://git.kernel.org/stable/c/8fb07fb1bba91d45846ed8605c3097fe67a7d54c",
        "https://git.kernel.org/stable/c/9334c88fc2fbc6836b307d269fcc1744c69701c0",
        "https://git.kernel.org/stable/c/d99dc8f7ea01ee1b21306e0eda8eb18a4af80db6",
        "https://git.kernel.org/stable/c/fd6aa1f8cbe0979eb66ac32ebc231bf0b10a2117",
        "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html",
        "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21943.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-21943",
        "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/2025/21xxx/CVE-2025-21943.json"
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    "related_cves": [
      {
        "value": "CVE-2025-21943",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 509779,
  "published_at": "2025-04-01T15:41:07.463+00:00"
}