CVE-2026-74448: drm/amdkfd: fix QID bit leak in pqm_create_queue()

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

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

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

drm/amdkfd: fix QID bit leak in pqm_create_queue()

When MES is enabled and amdgpu_amdkfd_alloc_kernel_mem() fails during
the first queue creation for a process, pqm_create_queue() returns
early via 'return retval' without going through the err_create_queue
cleanup label.

This means clear_bit(*qid, pqm->queue_slot_bitmap) is never called,
leaving the reserved QID bit permanently set in queue_slot_bitmap.
Over time this leaks QID slots, potentially exhausting all available
queue slots.

Fix this by replacing 'return retval' with 'goto err_allocate_pqn'
so that clear_bit() is always called on the error path without
touching the uninitialized pqn pointer.

AILIKFD-813

(cherry picked from commit a107f74c38edbb80d6ab64dcaeeb292c14e9779f)

The Linux kernel CVE team has assigned CVE-2026-74448 to this issue.


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

	Fixed in 6.6.151 with commit 8924e2594a15bdbd07f8696770864366d787ab70
	Fixed in 6.12.103 with commit 2ff5bb3645c72b3690e70c513a62a86600c4632f
	Fixed in 6.18.44 with commit 5f0f2ddeac738e2ca9d12cb76a1ff2904e85ecc3
	Fixed in 7.1.8 with commit 7c35bf94150d872e670a6632aa819d320279effb
	Fixed in 7.2-rc6 with commit 38b73293f38658a4685ffcea666462024f858ad9

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-2026-74448
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_process_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/8924e2594a15bdbd07f8696770864366d787ab70
	https://git.kernel.org/stable/c/2ff5bb3645c72b3690e70c513a62a86600c4632f
	https://git.kernel.org/stable/c/5f0f2ddeac738e2ca9d12cb76a1ff2904e85ecc3
	https://git.kernel.org/stable/c/7c35bf94150d872e670a6632aa819d320279effb
	https://git.kernel.org/stable/c/38b73293f38658a4685ffcea666462024f858ad9