CVE-2026-68427: gpu: host1x: Fix use-after-free in host1x_bo_clear_cached_mappings

CVE-2026-68427: gpu: host1x: Fix use-after-free in host1x_bo_clear_cached_mappings

[Greg Kroah-Hartman]

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

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

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

gpu: host1x: Fix use-after-free in host1x_bo_clear_cached_mappings

__host1x_bo_unpin() drops the last reference to the mapping and frees
it, so we can't dereference mapping afterwards. The cache itself
outlives the mapping, so use the cache local variable instead.

The Linux kernel CVE team has assigned CVE-2026-68427 to this issue.


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

	Fixed in 6.6.148 with commit abeff53233b984571b87582bb588b4b38ef4ea50
	Fixed in 6.12.101 with commit 5b7e5f84d3d4cea10c3764d2da274810a7934228
	Fixed in 6.18.42 with commit 5f4de3c717d34a24d555af581947742980778c02
	Fixed in 7.1.6 with commit b773faa32b0a98c3eb2b50d96de631681e5d1157
	Fixed in 7.2-rc4 with commit 266cddf7bd0f6c79b6c0633aef742a22bf70265b

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-2026-68427
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/gpu/host1x/bus.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/abeff53233b984571b87582bb588b4b38ef4ea50
	https://git.kernel.org/stable/c/5b7e5f84d3d4cea10c3764d2da274810a7934228
	https://git.kernel.org/stable/c/5f4de3c717d34a24d555af581947742980778c02
	https://git.kernel.org/stable/c/b773faa32b0a98c3eb2b50d96de631681e5d1157
	https://git.kernel.org/stable/c/266cddf7bd0f6c79b6c0633aef742a22bf70265b