CVE-2026-89446: iommufd: Release current IOAS on xa_store() failure

CVE-2026-89446: iommufd: Release current IOAS on xa_store() failure

[Greg Kroah-Hartman]

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

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

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

iommufd: Release current IOAS on xa_store() failure

iommufd_take_all_iova_rwsem() takes an object reference and the
iova_rwsem write lock before storing the IOAS in the temporary ioas_list
xarray.

If xa_store() fails, the current IOAS has not been inserted into
ioas_list yet. iommufd_release_all_iova_rwsem() only unwinds IOAS
objects already present in that xarray, so it cannot release the current
IOAS.

Release the current IOAS rwsem and object reference before unwinding the
previously stored entries.

The Linux kernel CVE team has assigned CVE-2026-89446 to this issue.


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

	Issue introduced in 6.13 with commit 051ae5aa73d782a8be2699a11e17c68f28b4e758 and fixed in 6.18.50 with commit 4c33d00ad9a911e87ea222986f732ce072e3aa26
	Issue introduced in 6.13 with commit 051ae5aa73d782a8be2699a11e17c68f28b4e758 and fixed in 7.2.4 with commit 07b4fe1367f076886c1c47a19c70936138325087
	Issue introduced in 6.13 with commit 051ae5aa73d782a8be2699a11e17c68f28b4e758 and fixed in 7.3-rc1 with commit 4ac2ce123824d5f885c868fa1f9f4d463141a2ba

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-2026-89446
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/iommu/iommufd/ioas.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/4c33d00ad9a911e87ea222986f732ce072e3aa26
	https://git.kernel.org/stable/c/07b4fe1367f076886c1c47a19c70936138325087
	https://git.kernel.org/stable/c/4ac2ce123824d5f885c868fa1f9f4d463141a2ba