iommu/vt-d: Skip dev-iotlb flush for inaccessible PCIe device without scalable mode

{
  "id": "10db0871c781582d6dc1a8da25ed604ba0e4ff35bacaca46c25cc8ae103005a9",
  "url": "https://osv.dev/vulnerability/CVE-2026-43161",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "iommu/vt-d: Skip dev-iotlb flush for inaccessible PCIe device without scalable mode",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: iommu/vt-d: Skip dev-iotlb flush for inaccessible PCIe device without scalable mode PCIe endpoints with ATS enabled and passed through to userspace (e.g., QEMU, DPDK) can hard-lock the host when their link drops, either by surprise removal or by a link fault. Commit 4fc82cd907ac (\"iommu/vt-d: Don't issue ATS Invalidation request when device is disconnected\") adds pci_dev_is_disconnected() to devtlb_invalidation_with_pasid() so ATS invalidation is skipped only when the device is being safely removed, but it applies only when Intel IOMMU scalable mode is enabled. With scalable mode disabled or unsupported, a system hard-lock occurs when a PCIe endpoint's link drops because the Intel IOMMU waits indefinitely for an ATS invalidation that cannot complete. Call Trace: qi_submit_sync qi_flush_dev_iotlb __context_flush_dev_iotlb.part.0 domain_context_clear_one_cb pci_for_each_dma_alias device_block_translation blocking_domain_attach_dev iommu_deinit_device __iommu_group_remove_device iommu_release_device iommu_bus_notifier blocking_notifier_call_chain bus_notify device_del pci_remove_bus_device pci_stop_and_remove_bus_device pciehp_unconfigure_device pciehp_disable_slot pciehp_handle_presence_or_link_change pciehp_ist Commit 81e921fd3216 (\"iommu/vt-d: Fix NULL domain on device release\") adds intel_pasid_teardown_sm_context() to intel_iommu_release_device(), which calls qi_flush_dev_iotlb() and can also hard-lock the ",
    "evidence": "osv:CVE-2026-43161",
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        "name": {
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        "prerequisites": [],
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    "severity": "unknown",
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      "modified": "2026-10-28T02:30:23.750793807Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/42662d19839f34735b718129ea200e3734b07e50",
        "https://git.kernel.org/stable/c/48b3f08e68b29a79527869cdde7298ca2a9b9646",
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        "https://git.kernel.org/stable/c/e70d5feb10c5ba2bbf7ca400b8f39a2f82d653e8",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43161.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-43161",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
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        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": null
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  "source_id": "core-osv",
  "document_id": 489873,
  "published_at": "2026-05-06T11:27:39.881+00:00"
}