firmware: arm_scmi: Drop handle on protocol bind failures

{
  "id": "57930c6aa6d79387dbcb1a88a02ac40b66776ea33f6b98b7c35d704457d8f9fb",
  "url": "https://osv.dev/vulnerability/CVE-2026-93084",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "firmware: arm_scmi: Drop handle on protocol bind failures",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: firmware: arm_scmi: Drop handle on protocol bind failures The SCMI bus notifier acquires an SCMI handle when the driver core emits BUS_NOTIFY_BIND_DRIVER, before invoking the protocol driver probe callback. The protocol probe path only checks whether sdev->handle is set. If device_link_add() fails after the handle has been acquired, the protocol device can still bind with a valid handle but without the dependency link to the SCMI parent. A concurrent parent unbind can then miss the child and tear down the SCMI instance while the child still holds a handle into it. If the protocol driver probe later fails, for example with -EPROBE_DEFER, the driver core emits BUS_NOTIFY_DRIVER_NOT_BOUND rather than BUS_NOTIFY_UNBOUND_DRIVER. The SCMI notifier only released the handle on BUS_NOTIFY_UNBOUND_DRIVER, so each failed protocol-device bind leaked the SCMI instance users refcount and left sdev->handle set after the failed probe. Make the link helper report failure and drop the acquired handle if the link cannot be created. Also handle BUS_NOTIFY_DRIVER_NOT_BOUND in the same cleanup path used for unbind so failed probes balance the earlier BUS_NOTIFY_BIND_DRIVER acquisition.",
    "evidence": "osv:CVE-2026-93084",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
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            "value": "6.6.157",
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            "evidence": "/affected/1/ranges"
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          {
            "value": "7.2.6",
            "evidence": "/affected/1/ranges"
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    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-93084",
      "aliases": [
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      ],
      "modified": "2026-11-01T02:30:48.770117062Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/0f860db24ee95e5da4866303a35e55098b9641b3",
        "https://git.kernel.org/stable/c/77d2985d1e80e67f32026fc03e975c4c83cc543d",
        "https://git.kernel.org/stable/c/a54dc23e8bd2246c28eafffa60b4634f0d1a11cc",
        "https://git.kernel.org/stable/c/b5377e690cd4fe87ee52fcf067c9929414ea8f4e",
        "https://git.kernel.org/stable/c/df273eced7cec550465fd1bb82a5d2c3c7d3c437",
        "https://git.kernel.org/stable/c/e3a5c30d233ca5d3e799a80da806554c703bda13",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93084.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-93084",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
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        "cna_assigner": "Linux",
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    "security_relevant": true,
    "severity_evidence": null
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  "source_id": "core-osv",
  "document_id": 518575,
  "published_at": "2026-09-17T16:11:03.659+00:00"
}