GHSA-JPH2-QVW9-VVWQ
Vulnerability from github – Published: 2026-05-06 12:30 – Updated: 2026-05-13 21:31In 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 system when a PCIe endpoint's link drops.
Call Trace: qi_submit_sync qi_flush_dev_iotlb __context_flush_dev_iotlb.part.0 intel_context_flush_no_pasid device_pasid_table_teardown pci_pasid_table_teardown pci_for_each_dma_alias intel_pasid_teardown_sm_context intel_iommu_release_device 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
Sometimes the endpoint loses connection without a link-down event (e.g., due to a link fault); killing the process (virsh destroy) then hard-locks the host.
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_attach_device __iommu_device_set_domain __iommu_group_set_domain_internal iommu_detach_group vfio_iommu_type1_detach_group vfio_group_detach_container vfio_group_fops_release __fput
pci_dev_is_disconnected() only covers safe-removal paths; pci_device_is_present() tests accessibility by reading vendor/device IDs and internally calls pci_dev_is_disconnected(). On a ConnectX-5 (8 GT/s, x2) this costs ~70 µs.
Since __context_flush_dev_iotlb() is only called on {attach,release}_dev paths (not hot), add pci_device_is_present() there to skip inaccessible devices and avoid the hard-lock.
{
"affected": [],
"aliases": [
"CVE-2026-43161"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-05-06T12:16:34Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\niommu/vt-d: Skip dev-iotlb flush for inaccessible PCIe device without scalable mode\n\nPCIe endpoints with ATS enabled and passed through to userspace\n(e.g., QEMU, DPDK) can hard-lock the host when their link drops,\neither by surprise removal or by a link fault.\n\nCommit 4fc82cd907ac (\"iommu/vt-d: Don\u0027t issue ATS Invalidation\nrequest when device is disconnected\") adds pci_dev_is_disconnected()\nto devtlb_invalidation_with_pasid() so ATS invalidation is skipped\nonly when the device is being safely removed, but it applies only\nwhen Intel IOMMU scalable mode is enabled.\n\nWith scalable mode disabled or unsupported, a system hard-lock\noccurs when a PCIe endpoint\u0027s link drops because the Intel IOMMU\nwaits indefinitely for an ATS invalidation that cannot complete.\n\nCall Trace:\n qi_submit_sync\n qi_flush_dev_iotlb\n __context_flush_dev_iotlb.part.0\n domain_context_clear_one_cb\n pci_for_each_dma_alias\n device_block_translation\n blocking_domain_attach_dev\n iommu_deinit_device\n __iommu_group_remove_device\n iommu_release_device\n iommu_bus_notifier\n blocking_notifier_call_chain\n bus_notify\n device_del\n pci_remove_bus_device\n pci_stop_and_remove_bus_device\n pciehp_unconfigure_device\n pciehp_disable_slot\n pciehp_handle_presence_or_link_change\n pciehp_ist\n\nCommit 81e921fd3216 (\"iommu/vt-d: Fix NULL domain on device release\")\nadds intel_pasid_teardown_sm_context() to intel_iommu_release_device(),\nwhich calls qi_flush_dev_iotlb() and can also hard-lock the system\nwhen a PCIe endpoint\u0027s link drops.\n\nCall Trace:\n qi_submit_sync\n qi_flush_dev_iotlb\n __context_flush_dev_iotlb.part.0\n intel_context_flush_no_pasid\n device_pasid_table_teardown\n pci_pasid_table_teardown\n pci_for_each_dma_alias\n intel_pasid_teardown_sm_context\n intel_iommu_release_device\n iommu_deinit_device\n __iommu_group_remove_device\n iommu_release_device\n iommu_bus_notifier\n blocking_notifier_call_chain\n bus_notify\n device_del\n pci_remove_bus_device\n pci_stop_and_remove_bus_device\n pciehp_unconfigure_device\n pciehp_disable_slot\n pciehp_handle_presence_or_link_change\n pciehp_ist\n\nSometimes the endpoint loses connection without a link-down event\n(e.g., due to a link fault); killing the process (virsh destroy)\nthen hard-locks the host.\n\nCall Trace:\n qi_submit_sync\n qi_flush_dev_iotlb\n __context_flush_dev_iotlb.part.0\n domain_context_clear_one_cb\n pci_for_each_dma_alias\n device_block_translation\n blocking_domain_attach_dev\n __iommu_attach_device\n __iommu_device_set_domain\n __iommu_group_set_domain_internal\n iommu_detach_group\n vfio_iommu_type1_detach_group\n vfio_group_detach_container\n vfio_group_fops_release\n __fput\n\npci_dev_is_disconnected() only covers safe-removal paths;\npci_device_is_present() tests accessibility by reading\nvendor/device IDs and internally calls pci_dev_is_disconnected().\nOn a ConnectX-5 (8 GT/s, x2) this costs ~70 \u00b5s.\n\nSince __context_flush_dev_iotlb() is only called on\n{attach,release}_dev paths (not hot), add pci_device_is_present()\nthere to skip inaccessible devices and avoid the hard-lock.",
"id": "GHSA-jph2-qvw9-vvwq",
"modified": "2026-05-13T21:31:58Z",
"published": "2026-05-06T12:30:31Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43161"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/42662d19839f34735b718129ea200e3734b07e50"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/48b3f08e68b29a79527869cdde7298ca2a9b9646"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/bc0490ad9edf5c6f98e39fbbee2877b85261a5ae"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e70d5feb10c5ba2bbf7ca400b8f39a2f82d653e8"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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