CVE-2026-45931: accel/amdxdna: Hold mm structure across iommu_sva_unbind_device()

CVE-2026-45931: accel/amdxdna: Hold mm structure across iommu_sva_unbind_device()

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

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

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

accel/amdxdna: Hold mm structure across iommu_sva_unbind_device()

Some tests trigger a crash in iommu_sva_unbind_device() due to
accessing iommu_mm after the associated mm structure has been
freed.

Fix this by taking an explicit reference to the mm structure
after successfully binding the device, and releasing it only
after the device is unbound. This ensures the mm remains valid
for the entire SVA bind/unbind lifetime.

The Linux kernel CVE team has assigned CVE-2026-45931 to this issue.


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

	Issue introduced in 6.14 with commit be462c97b7dfd24999babe39cce3de224ebe1f80 and fixed in 6.18.14 with commit f6b4c1d98a7b8040d4d02e89425b3942016a2c2c
	Issue introduced in 6.14 with commit be462c97b7dfd24999babe39cce3de224ebe1f80 and fixed in 6.19.4 with commit f31ccf6278132a35a652fe5eeac3941e1e912398
	Issue introduced in 6.14 with commit be462c97b7dfd24999babe39cce3de224ebe1f80 and fixed in 7.0 with commit a9162439ad792afcddc04718408ec1380b7a5f63

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-2026-45931
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/accel/amdxdna/amdxdna_pci_drv.c
	drivers/accel/amdxdna/amdxdna_pci_drv.h


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/f6b4c1d98a7b8040d4d02e89425b3942016a2c2c
	https://git.kernel.org/stable/c/f31ccf6278132a35a652fe5eeac3941e1e912398
	https://git.kernel.org/stable/c/a9162439ad792afcddc04718408ec1380b7a5f63