CVE-2026-52949: drm/ttm: Fix ttm_bo_shrink() infinite LRU walk on backup failure

CVE-2026-52949: drm/ttm: Fix ttm_bo_shrink() infinite LRU walk on backup failure

[Greg Kroah-Hartman]

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

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

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

drm/ttm: Fix ttm_bo_shrink() infinite LRU walk on backup failure

Apply the same fix as b2ed01e7ad ("drm/ttm: Fix ttm_bo_swapout()
infinite LRU walk on swapout failure") to the ttm_bo_shrink() path.

Move del_bulk_move from before the backup to after success only,
using ttm_resource_del_bulk_move_unevictable() since the resource
is now unevictable once fully backed up.

The Linux kernel CVE team has assigned CVE-2026-52949 to this issue.


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

	Issue introduced in 6.15 with commit 70d645deac98303d1bf9ab08a4e68da52bf8c1e1 and fixed in 7.0.10 with commit 9402ad98a047dd9894ec868a7df5ad9bd03327d3
	Issue introduced in 6.15 with commit 70d645deac98303d1bf9ab08a4e68da52bf8c1e1 and fixed in 7.1 with commit 1d59f36e95f7f7134db0e313c9d787cb0adb2153

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-2026-52949
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/ttm/ttm_bo_util.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/9402ad98a047dd9894ec868a7df5ad9bd03327d3
	https://git.kernel.org/stable/c/1d59f36e95f7f7134db0e313c9d787cb0adb2153