CVE-2026-89811: drm/amdkfd: Add TLB flush after MES queue eviction/suspension

CVE-2026-89811: drm/amdkfd: Add TLB flush after MES queue eviction/suspension

[Greg Kroah-Hartman]

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

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

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

drm/amdkfd: Add TLB flush after MES queue eviction/suspension

MES (Micro Engine Scheduler) does not perform heavy-weight TLB
invalidation after unmapping queues, unlike HWS which does this
automatically. This causes a race condition where in-flight DMA
descriptors can access memory that has been unmapped, leading to page
faults and GPU queue hangs during SVM page migration.

The issue manifests as KFDSVMRangeTest.MultiThreadMigrationTest
failures on gfx1151 (Strix Point) with XNACK mode 1 enabled - the GPU
compute queue hangs with packets submitted but never consumed.

Add kfd_flush_tlb() calls after MES queue removal in two locations:
- evict_process_queues_cpsch(): after all queues removed during eviction
- suspend_queues(): after debug/criu queue suspension (with mem_fence barrier)

This ensures all in-flight memory accesses from unmapped queues are
flushed before memory is freed or migrated.

(cherry picked from commit f5c4f88e0f9c45a8fb9dfac0c1df726c95e41b77)

The Linux kernel CVE team has assigned CVE-2026-89811 to this issue.


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

	Fixed in 6.18.51 with commit e230c546ed93741833ab5babb0b202f9c2052b45
	Fixed in 7.2.5 with commit 6aae545c87087e4dc96e205452243813bfa73ba2
	Fixed in 7.3-rc2 with commit 94e25cb6ab7f4f025bcdcd8ea79fda30f12843a4

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-2026-89811
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/amd/amdkfd/kfd_device_queue_manager.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/e230c546ed93741833ab5babb0b202f9c2052b45
	https://git.kernel.org/stable/c/6aae545c87087e4dc96e205452243813bfa73ba2
	https://git.kernel.org/stable/c/94e25cb6ab7f4f025bcdcd8ea79fda30f12843a4