Bug 2506776 (CVE-2026-64254)

Summary:	CVE-2026-64254 kernel: NTB: epf: Avoid pci_iounmap() with offset when PEER_SPAD and CONFIG share BAR
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability-draft	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-07-24 16:01:41 UTC

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

NTB: epf: Avoid pci_iounmap() with offset when PEER_SPAD and CONFIG share BAR

When BAR_PEER_SPAD and BAR_CONFIG share one PCI BAR, the module teardown
path ends up calling pci_iounmap() on the same iomem with some offset,
which is unnecessary and triggers a kernel warning like the following:

  Trying to vunmap() nonexistent vm area (0000000069a5ffe8)
  WARNING: mm/vmalloc.c:3470 at vunmap+0x58/0x68, CPU#5: modprobe/2937
  [...]
  Call trace:
   vunmap+0x58/0x68 (P)
   iounmap+0x34/0x48
   pci_iounmap+0x2c/0x40
   ntb_epf_pci_remove+0x44/0x80 [ntb_hw_epf]
   pci_device_remove+0x48/0xf8
   device_remove+0x50/0x88
   device_release_driver_internal+0x1c8/0x228
   driver_detach+0x50/0xb0
   bus_remove_driver+0x74/0x100
   driver_unregister+0x34/0x68
   pci_unregister_driver+0x34/0xa0
   ntb_epf_pci_driver_exit+0x14/0xfe0 [ntb_hw_epf]
  [...]

Fix it by unmapping only when PEER_SPAD and CONFIG use difference bars.

Comment 1 Mauro Matteo Cascella 2026-07-28 08:41:59 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072420-CVE-2026-64254-0322@gregkh/T