CVE-2025-39958
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-10-09

Last updated on: 2026-02-26

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: iommu/s390: Make attach succeed when the device was surprise removed When a PCI device is removed with surprise hotplug, there may still be attempts to attach the device to the default domain as part of tear down via (__iommu_release_dma_ownership()), or because the removal happens during probe (__iommu_probe_device()). In both cases zpci_register_ioat() fails with a cc value indicating that the device handle is invalid. This is because the device is no longer part of the instance as far as the hypervisor is concerned. Currently this leads to an error return and s390_iommu_attach_device() fails. This triggers the WARN_ON() in __iommu_group_set_domain_nofail() because attaching to the default domain must never fail. With the device fenced by the hypervisor no DMAs to or from memory are possible and the IOMMU translations have no effect. Proceed as if the registration was successful and let the hotplug event handling clean up the device. This is similar to how devices in the error state are handled since commit 59bbf596791b ("iommu/s390: Make attach succeed even if the device is in error state") except that for removal the domain will not be registered later. This approach was also previously discussed at the link. Handle both cases, error state and removal, in a helper which checks if the error needs to be propagated or ignored. Avoid magic number condition codes by using the pre-existing, but never used, defines for PCI load/store condition codes and rename them to reflect that they apply to all PCI instructions.
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Meta Information
Published
2025-10-09
Last Modified
2026-02-26
Generated
2026-05-06
AI Q&A
2025-10-09
EPSS Evaluated
2026-05-05
NVD
CVE-2025-39958
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
linux linux_kernel 6.17
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability occurs in the Linux kernel's s390 iommu subsystem when a PCI device is surprise removed (hotplugged out unexpectedly). Attempts to attach the removed device to the default domain fail because the device handle becomes invalid as the hypervisor no longer recognizes the device. This failure triggers warnings and errors in the kernel. The fix makes the attach operation succeed even if the device is removed or in an error state, allowing the system to handle the hotplug event cleanly without errors.


How can this vulnerability impact me? :

If unpatched, this vulnerability can cause errors and warnings in the kernel when a PCI device is surprise removed, potentially leading to instability or improper handling of device removal events. However, with the fix, the system proceeds as if the registration was successful, preventing such errors and ensuring proper cleanup. The impact is mainly on system stability and correct device hotplug handling on s390 platforms.


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