CVE-2026-43370: drm/amdgpu: Fix use-after-free race in VM acquire

CVE-2026-43370: drm/amdgpu: Fix use-after-free race in VM acquire

[Greg Kroah-Hartman]

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

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

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

drm/amdgpu: Fix use-after-free race in VM acquire

Replace non-atomic vm->process_info assignment with cmpxchg()
to prevent race when parent/child processes sharing a drm_file
both try to acquire the same VM after fork().

(cherry picked from commit c7c573275ec20db05be769288a3e3bb2250ec618)

The Linux kernel CVE team has assigned CVE-2026-43370 to this issue.


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

	Fixed in 5.10.253 with commit ae87aea330c24f462fc7058ed543ba8bc6798447
	Fixed in 5.15.203 with commit 46d309996bd9251792d7dafdbaf615cf202b4447
	Fixed in 6.1.167 with commit e61e355cbe49e585097eee28c15b862bfb1c0668
	Fixed in 6.6.130 with commit c658c1c85ec235b7ecfbf8dbfee385b1332088f4
	Fixed in 6.12.78 with commit 904025fa8bba1d028adade33346372b4ac1a9249
	Fixed in 6.18.19 with commit 7885eb335d8f9e9942925d57e300a85e3f82ded4
	Fixed in 6.19.9 with commit 94b7782d0c8024f5b88454241c8d4777076c3786
	Fixed in 7.0 with commit 2c1030f2e84885cc58bffef6af67d5b9d2e7098f

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-2026-43370
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/amdgpu/amdgpu_amdkfd_gpuvm.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/ae87aea330c24f462fc7058ed543ba8bc6798447
	https://git.kernel.org/stable/c/46d309996bd9251792d7dafdbaf615cf202b4447
	https://git.kernel.org/stable/c/e61e355cbe49e585097eee28c15b862bfb1c0668
	https://git.kernel.org/stable/c/c658c1c85ec235b7ecfbf8dbfee385b1332088f4
	https://git.kernel.org/stable/c/904025fa8bba1d028adade33346372b4ac1a9249
	https://git.kernel.org/stable/c/7885eb335d8f9e9942925d57e300a85e3f82ded4
	https://git.kernel.org/stable/c/94b7782d0c8024f5b88454241c8d4777076c3786
	https://git.kernel.org/stable/c/2c1030f2e84885cc58bffef6af67d5b9d2e7098f