---
id: CVE-2026-89795
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  PCI: Allow per function PCI slots to fix slot reset on s390

  On s390 systems, which use a machine level hypervisor, PCI devices are
  always accessed through a form of PC…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  PCI: Allow per function PCI slots to fix slot reset on s390

  On s390 systems, which use a machine level hypervisor, PCI devices are
  always accessed through a form of PC…
severity: high
cvss: 8.4
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 44510d6fa0c00aa90b80075caa6b313b25927475 <
    2050d900f9adbd6d6f38d30e182bcd9ad3108467
  - >-
    Linux >= 44510d6fa0c00aa90b80075caa6b313b25927475 <
    ecdcceed4d377b02d4ea036b65f83f962c38ede7
  - >-
    Linux >= 44510d6fa0c00aa90b80075caa6b313b25927475 <
    dcc5bec09e23bbc4f9de055a11fce9937244f2c8
  - Linux 5.8
published: '2026-09-16'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T15:18:09.640'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89795'
references:
  - url: 'https://git.kernel.org/stable/c/2050d900f9adbd6d6f38d30e182bcd9ad3108467'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/dcc5bec09e23bbc4f9de055a11fce9937244f2c8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ecdcceed4d377b02d4ea036b65f83f962c38ede7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-16T10:53:54.011Z'
epss: 0.00158
epssPercentile: 0.05329
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

PCI: Allow per function PCI slots to fix slot reset on s390

On s390 systems, which use a machine level hypervisor, PCI devices are
always accessed through a form of PCI pass-through which fundamentally
operates on a per PCI function granularity. This is also reflected in the
s390 PCI hotplug driver which creates hotplug slots for individual PCI
functions. Its reset_slot() function, which is a wrapper for
zpci_hot_reset_device(), thus also resets individual functions.

Currently, the pci_create_slot() assigns the same pci_slot object to
multifunction devices. This approach worked fine on s390 systems that only
exposed virtual functions as individual PCI domains to the operating
system.  Since commit 44510d6fa0c0 ("s390/pci: Handling multifunctions")
s390 supports exposing the topology of multifunction PCI devices by
grouping them in a shared PCI domain. This creates a problem when resetting
a function through the hotplug driver's slot_reset() interface.

When attempting to reset a function through the hotplug driver, the shared
slot assignment causes the wrong function to be reset instead of the
intended one. It also leaks memory as we do create a pci_slot object for
the function, but don't correctly free it in pci_slot_release().

Add a flag for struct pci_slot to allow per function PCI slots for
functions managed through a hypervisor, which exposes individual PCI
functions while retaining the topology. Since we can use all 8 bits for
slot 'number' (for ARI devices), change slot 'number' u16 to account for
special values PCI_SLOT_PLACEHOLDER and PCI_SLOT_ALL_DEVICES.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.