CVE-2026-80915: drm/xe: Fix DPT allocation paths.

CVE-2026-80915: drm/xe: Fix DPT allocation paths.

[Greg Kroah-Hartman]

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

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

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

drm/xe: Fix DPT allocation paths.

Remove the fallback for VRAM to system memory, I tested it and that
doesn't work at all, only a black screen with pipe fault errors were
observed.

On systems with media GT, extra latency is added when accessing stolen
memory when the GT is in MC6. Since we additionally aren't counting how
much memory is used for stolen and we could in theory fill up the
entire stolen area with DPT's, avoid using stolen and only use the
default memory region.

Using stolen may also result in random system hangs under load.

(cherry picked from commit a196406a3831291598fe8e73245914f7acffdfe0)

The Linux kernel CVE team has assigned CVE-2026-80915 to this issue.


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

	Issue introduced in 6.12 with commit 775d0adc01a55fe0458139330415d86bb3533efe and fixed in 6.12.106 with commit 491c499295fb0b90308b230b0a1075dcdf7f4d12
	Issue introduced in 6.12 with commit 775d0adc01a55fe0458139330415d86bb3533efe and fixed in 6.18.47 with commit f03415030579163f791c978741af7f1f2f6510b7
	Issue introduced in 6.12 with commit 775d0adc01a55fe0458139330415d86bb3533efe and fixed in 7.1.11 with commit c457e2c845ccbf2224386029f3da4937ba424db0
	Issue introduced in 6.12 with commit 775d0adc01a55fe0458139330415d86bb3533efe and fixed in 7.2 with commit fc648757908304aedbad74f74bf58192aec383db
	Issue introduced in 6.11.3 with commit 4854ac2f88e2168ee4da2b152c6711772a8149aa

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-2026-80915
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/drm/xe/display/xe_fb_pin.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/491c499295fb0b90308b230b0a1075dcdf7f4d12
	https://git.kernel.org/stable/c/f03415030579163f791c978741af7f1f2f6510b7
	https://git.kernel.org/stable/c/c457e2c845ccbf2224386029f3da4937ba424db0
	https://git.kernel.org/stable/c/fc648757908304aedbad74f74bf58192aec383db