CVE-2026-64254: NTB: epf: Avoid pci_iounmap() with offset when PEER_SPAD and CONFIG share BAR

From: Greg Kroah-Hartman <[email protected]>

Description
===========

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.

The Linux kernel CVE team has assigned CVE-2026-64254 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.0 with commit e75d5ae8ab88b7ffb3d1d56124b003f3555f74b4 and fixed in 6.1.177 with commit eb47b9bffd07a47b84910847cb5ea066ce184055
	Issue introduced in 6.0 with commit e75d5ae8ab88b7ffb3d1d56124b003f3555f74b4 and fixed in 6.6.144 with commit 06f6dd2ff2bd07eaf7178a807407ff27e85122b4
	Issue introduced in 6.0 with commit e75d5ae8ab88b7ffb3d1d56124b003f3555f74b4 and fixed in 6.12.95 with commit a4be4a1308f02bff79a30eea2d04ead5b63685f2
	Issue introduced in 6.0 with commit e75d5ae8ab88b7ffb3d1d56124b003f3555f74b4 and fixed in 6.18.38 with commit 81371dbd23601f67f01372817fdbab42c5601e43
	Issue introduced in 6.0 with commit e75d5ae8ab88b7ffb3d1d56124b003f3555f74b4 and fixed in 7.1.3 with commit 9764a786ba98db58f0725913c369e721253aba33
	Issue introduced in 6.0 with commit e75d5ae8ab88b7ffb3d1d56124b003f3555f74b4 and fixed in 7.2-rc1 with commit d876153680e3d721d385e554def919bce3d18c74

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-64254
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/ntb/hw/epf/ntb_hw_epf.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/eb47b9bffd07a47b84910847cb5ea066ce184055
	https://git.kernel.org/stable/c/06f6dd2ff2bd07eaf7178a807407ff27e85122b4
	https://git.kernel.org/stable/c/a4be4a1308f02bff79a30eea2d04ead5b63685f2
	https://git.kernel.org/stable/c/81371dbd23601f67f01372817fdbab42c5601e43
	https://git.kernel.org/stable/c/9764a786ba98db58f0725913c369e721253aba33
	https://git.kernel.org/stable/c/d876153680e3d721d385e554def919bce3d18c74