---
id: CVE-2026-98166
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  drm/ttm: fix swapped-out resources never leaving their bulk_move range

  ttm_tt_swapout() returns the number of pages swapped out on success and
  a negative error code on…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  drm/ttm: fix swapped-out resources never leaving their bulk_move range

  ttm_tt_swapout() returns the number of pages swapped out on success and
  a negative error code on…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= b2ed01e7ad3de80333e9b962a44024b094bc0b2b <
    1169fe8c11ca45e3f91d59a73eb271d0ca8a7fb0
  - >-
    Linux >= b2ed01e7ad3de80333e9b962a44024b094bc0b2b <
    3db7d7d583419f7b1f2e141e36418802dbb25cf8
  - Linux 0124a09e3e5f5f6080efe9663b27af27933f8382
  - Linux >= 7.0.10 < 7.1
  - Linux 7.1
published: '2026-10-06'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T09:17:58.033'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98166'
references:
  - url: 'https://git.kernel.org/stable/c/1169fe8c11ca45e3f91d59a73eb271d0ca8a7fb0'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/3db7d7d583419f7b1f2e141e36418802dbb25cf8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-06T08:50:17.459Z'
---

## Overview

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

drm/ttm: fix swapped-out resources never leaving their bulk_move range

ttm_tt_swapout() returns the number of pages swapped out on success and
a negative error code on failure; for a populated ttm it never returns
zero. Commit b2ed01e7ad3d ("drm/ttm: Fix ttm_bo_swapout() infinite LRU
walk on swapout failure") moved the bulk_move bookkeeping in
ttm_bo_swapout_cb() under "if (!ret)", so the
ttm_resource_del_bulk_move_unevictable() / ttm_resource_move_to_lru_tail()
pair is now skipped on every successful swapout. The equivalent change
for the shrinker in commit 1d59f36e95f7 ("drm/ttm: Fix ttm_bo_shrink()
infinite LRU walk on backup failure") tests "lret > 0", which is what
was intended here as well.

Before b2ed01e7ad3d the resource was taken off the bulk_move before the
swapout; since then a swapped-out resource stays inside its BO's
bulk_move range (and on the manager LRU) although it is unevictable.
When it is later freed or the BO leaves the bulk_move
(ttm_resource_free(), ttm_bo_set_bulk_move() via amdgpu_vm_bo_del()),
ttm_resource_del_bulk_move() skips it because of its
!ttm_resource_unevictable() guard, so a range endpoint in pos->first /
pos->last is left pointing at freed memory. The next
ttm_lru_bulk_move_tail() or ttm_resource_add_bulk_move() on that cursor
is a use-after-free, seen as the resv WARN in ttm_lru_bulk_move_add(),
"list_del corruption" in ttm_resource_move_to_lru_tail() or a NULL
dereference in ttm_resource_manager_next() -- minutes to hours after a
hibernation, or at process exit / reboot following one. Samuel
Ainsworth's analysis of drm/amd issue 5387 (see Link) identified the
dangling cursor; the missing removal at swapout time is the reason it
dangles.

Testing the condition for success restores the removal. On an AMD
Phoenix APU (ASUS UM3406GA, gfx1103) running suspend-then-hibernate on
a 7.0.y stable kernel carrying the backport (Ubuntu 7.0.0-31) the bug
crashed 5 of 18 hibernation cycles; a function profile of one
hibernation showed 336 ttm_tt_swapout() calls and zero
ttm_resource_del_bulk_move_unevictable() calls. With this change the
removal happens for every swapped-out resource and 12 further cycles
were clean.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.