CVE-2026-68447: drm/amdkfd: clamp v9 CRIU control stack checkpoint copy to BO size

From: Greg Kroah-Hartman <[email protected]>

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

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

drm/amdkfd: clamp v9 CRIU control stack checkpoint copy to BO size

CRIU checkpoint copies the MQD control stack using cp_hqd_cntl_stack_size
from hardware without bounding it to the allocated BO region. If the HW
field is larger than the queue's control stack allocation, memcpy reads
past the BO into adjacent GTT memory and can leak kernel data to userspace.

Store the page-aligned control stack BO size in mqd_manager and clamp
checkpoint copies and reported checkpoint sizes to
min(cp_hqd_cntl_stack_size, mm->ctl_stack_size). Apply the same bound
for multi-XCC v9.4.3 checkpoint layout.

(cherry picked from commit 6c2abd0ec09e86c6323010673766f76050e28aa3)

The Linux kernel CVE team has assigned CVE-2026-68447 to this issue.


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

	Fixed in 7.1.6 with commit a0d87beb2660a5098b2b0ecdc1e96810a9074ea9
	Fixed in 7.2-rc2 with commit 426ffae6ecc7ec77d32bf8be065c21a1b881b084

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-2026-68447
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_mqd_manager.h
	drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.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/a0d87beb2660a5098b2b0ecdc1e96810a9074ea9
	https://git.kernel.org/stable/c/426ffae6ecc7ec77d32bf8be065c21a1b881b084