linux-cve-announce - CVE-2025-40340: drm/xe: Fix oops in xe_gem_fault when running core

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Message-ID: <2025120912-CVE-2025-40340-4d41@gregkh>
Date: Tue,  9 Dec 2025 13:10:22 +0900
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-40340: drm/xe: Fix oops in xe_gem_fault when running core_hotunplug test.

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

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

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

drm/xe: Fix oops in xe_gem_fault when running core_hotunplug test.

I saw an oops in xe_gem_fault when running the xe-fast-feedback
testlist against the realtime kernel without debug options enabled.

The panic happens after core_hotunplug unbind-rebind finishes.
Presumably what happens is that a process mmaps, unlocks because
of the FAULT_FLAG_RETRY_NOWAIT logic, has no process memory left,
causing ttm_bo_vm_dummy_page() to return VM_FAULT_NOPAGE, since
there was nothing left to populate, and then oopses in
"mem_type_is_vram(tbo->resource->mem_type)" because tbo->resource
is NULL.

It's convoluted, but fits the data and explains the oops after
the test exits.

The Linux kernel CVE team has assigned CVE-2025-40340 to this issue.

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

	Fixed in 6.12.58 with commit 99428bd6123d5676209dfb1d7a8f176cc830b665
	Fixed in 6.17.8 with commit 29a3064f9c5a908aaf0b39cd6ed30374db11840d
	Fixed in 6.18 with commit 1cda3c755bb7770be07d75949bb0f45fb88651f6

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-2025-40340
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/xe_bo.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/99428bd6123d5676209dfb1d7a8f176cc830b665
	https://git.kernel.org/stable/c/29a3064f9c5a908aaf0b39cd6ed30374db11840d
	https://git.kernel.org/stable/c/1cda3c755bb7770be07d75949bb0f45fb88651f6