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GHSA-62XR-3QF5-9QPJ

Vulnerability from github – Published: 2026-10-06 09:31 – Updated: 2026-10-07 09:32

Details

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.

Severity

7.8 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-98166"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-06T09:17:58Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/ttm: fix swapped-out resources never leaving their bulk_move range\n\nttm_tt_swapout() returns the number of pages swapped out on success and\na negative error code on failure; for a populated ttm it never returns\nzero. Commit b2ed01e7ad3d (\"drm/ttm: Fix ttm_bo_swapout() infinite LRU\nwalk on swapout failure\") moved the bulk_move bookkeeping in\nttm_bo_swapout_cb() under \"if (!ret)\", so the\nttm_resource_del_bulk_move_unevictable() / ttm_resource_move_to_lru_tail()\npair is now skipped on every successful swapout. The equivalent change\nfor the shrinker in commit 1d59f36e95f7 (\"drm/ttm: Fix ttm_bo_shrink()\ninfinite LRU walk on backup failure\") tests \"lret \u003e 0\", which is what\nwas intended here as well.\n\nBefore b2ed01e7ad3d the resource was taken off the bulk_move before the\nswapout; since then a swapped-out resource stays inside its BO\u0027s\nbulk_move range (and on the manager LRU) although it is unevictable.\nWhen it is later freed or the BO leaves the bulk_move\n(ttm_resource_free(), ttm_bo_set_bulk_move() via amdgpu_vm_bo_del()),\nttm_resource_del_bulk_move() skips it because of its\n!ttm_resource_unevictable() guard, so a range endpoint in pos-\u003efirst /\npos-\u003elast is left pointing at freed memory. The next\nttm_lru_bulk_move_tail() or ttm_resource_add_bulk_move() on that cursor\nis a use-after-free, seen as the resv WARN in ttm_lru_bulk_move_add(),\n\"list_del corruption\" in ttm_resource_move_to_lru_tail() or a NULL\ndereference in ttm_resource_manager_next() -- minutes to hours after a\nhibernation, or at process exit / reboot following one. Samuel\nAinsworth\u0027s analysis of drm/amd issue 5387 (see Link) identified the\ndangling cursor; the missing removal at swapout time is the reason it\ndangles.\n\nTesting the condition for success restores the removal. On an AMD\nPhoenix APU (ASUS UM3406GA, gfx1103) running suspend-then-hibernate on\na 7.0.y stable kernel carrying the backport (Ubuntu 7.0.0-31) the bug\ncrashed 5 of 18 hibernation cycles; a function profile of one\nhibernation showed 336 ttm_tt_swapout() calls and zero\nttm_resource_del_bulk_move_unevictable() calls. With this change the\nremoval happens for every swapped-out resource and 12 further cycles\nwere clean.",
  "id": "GHSA-62xr-3qf5-9qpj",
  "modified": "2026-10-07T09:32:12Z",
  "published": "2026-10-06T09:31:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98166"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1169fe8c11ca45e3f91d59a73eb271d0ca8a7fb0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3db7d7d583419f7b1f2e141e36418802dbb25cf8"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-98166 (GCVE-0-2026-98166)

Vulnerability from cvelistv5 – Published: 2026-10-06 08:44 – Updated: 2026-10-07 06:49

Title

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

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 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.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root Scorecard

References

2 references

URL	Tags
https://git.kernel.org/stable/c/1169fe8c11ca45e3f…
https://git.kernel.org/stable/c/3db7d7d583419f7b1…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: b2ed01e7ad3de80333e9b962a44024b094bc0b2b , < 1169fe8c11ca45e3f91d59a73eb271d0ca8a7fb0 (git) Affected: b2ed01e7ad3de80333e9b962a44024b094bc0b2b , < 3db7d7d583419f7b1f2e141e36418802dbb25cf8 (git) Affected: 0124a09e3e5f5f6080efe9663b27af27933f8382 (git) Affected: 7.0.10 , < 7.1 (semver)
Linux	Linux	Affected: 7.1 Unaffected: 0 , < 7.1 (semver) Unaffected: 7.2.8 , ≤ 7.2.* (semver) Unaffected: 7.3-rc4 , ≤ * (original_commit_for_fix)

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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/ttm/ttm_bo.c"
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "lessThan": "1169fe8c11ca45e3f91d59a73eb271d0ca8a7fb0",
              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "3db7d7d583419f7b1f2e141e36418802dbb25cf8",
              "status": "affected",
              "version": "b2ed01e7ad3de80333e9b962a44024b094bc0b2b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "0124a09e3e5f5f6080efe9663b27af27933f8382",
              "versionType": "git"
            },
            {
              "lessThan": "7.1",
              "status": "affected",
              "version": "7.0.10",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/ttm/ttm_bo.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.1"
            },
            {
              "lessThan": "7.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc4",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.8",
                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc4",
                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "7.0.10",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/ttm: fix swapped-out resources never leaving their bulk_move range\n\nttm_tt_swapout() returns the number of pages swapped out on success and\na negative error code on failure; for a populated ttm it never returns\nzero. Commit b2ed01e7ad3d (\"drm/ttm: Fix ttm_bo_swapout() infinite LRU\nwalk on swapout failure\") moved the bulk_move bookkeeping in\nttm_bo_swapout_cb() under \"if (!ret)\", so the\nttm_resource_del_bulk_move_unevictable() / ttm_resource_move_to_lru_tail()\npair is now skipped on every successful swapout. The equivalent change\nfor the shrinker in commit 1d59f36e95f7 (\"drm/ttm: Fix ttm_bo_shrink()\ninfinite LRU walk on backup failure\") tests \"lret \u003e 0\", which is what\nwas intended here as well.\n\nBefore b2ed01e7ad3d the resource was taken off the bulk_move before the\nswapout; since then a swapped-out resource stays inside its BO\u0027s\nbulk_move range (and on the manager LRU) although it is unevictable.\nWhen it is later freed or the BO leaves the bulk_move\n(ttm_resource_free(), ttm_bo_set_bulk_move() via amdgpu_vm_bo_del()),\nttm_resource_del_bulk_move() skips it because of its\n!ttm_resource_unevictable() guard, so a range endpoint in pos-\u003efirst /\npos-\u003elast is left pointing at freed memory. The next\nttm_lru_bulk_move_tail() or ttm_resource_add_bulk_move() on that cursor\nis a use-after-free, seen as the resv WARN in ttm_lru_bulk_move_add(),\n\"list_del corruption\" in ttm_resource_move_to_lru_tail() or a NULL\ndereference in ttm_resource_manager_next() -- minutes to hours after a\nhibernation, or at process exit / reboot following one. Samuel\nAinsworth\u0027s analysis of drm/amd issue 5387 (see Link) identified the\ndangling cursor; the missing removal at swapout time is the reason it\ndangles.\n\nTesting the condition for success restores the removal. On an AMD\nPhoenix APU (ASUS UM3406GA, gfx1103) running suspend-then-hibernate on\na 7.0.y stable kernel carrying the backport (Ubuntu 7.0.0-31) the bug\ncrashed 5 of 18 hibernation cycles; a function profile of one\nhibernation showed 336 ttm_tt_swapout() calls and zero\nttm_resource_del_bulk_move_unevictable() calls. With this change the\nremoval happens for every swapped-out resource and 12 further cycles\nwere clean."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The attacker drives ttm_bo_swapout_cb() through local DRM render-node ioctls (amdgpu GEM_CREATE with VM_ALWAYS_VALID, then CS), with ttm_tt_populate() calling ttm_global_swapout() once ttm_pages_limit is exceeded, or through hibernation. No remote protocol carries any input.\nAC:L - Hibernation is not needed: the attacker allocates per-VM BOs past ttm_pages_limit to force swapout, closes the swapped BO so ttm_resource_free() frees a resource still referenced by the bulk_move cursor, then submits CS to run ttm_lru_bulk_move_tail(). Every step is the attacker\u0027s own action.\nPR:L - AMDGPU_GEM_CREATE, GEM_CLOSE and AMDGPU_CS are DRM_RENDER_ALLOW ioctls on /dev/dri/renderD*, open to an ordinary render-group or seat user without root or capabilities.\nUI:N - The attacker runs the whole sequence in their own process with their own buffer objects. No other user has to act.\nS:U - The freed ttm_resource and the corrupted manager LRU lists are kernel memory, so the impact stays within the kernel\u0027s own security authority.\nC:H - After ttm_resource_free() frees the swapped resource, bulk_move pos-\u003efirst/pos-\u003elast still point at it, so a reallocated object can be read and walked as a ttm_resource by ttm_lru_bulk_move_tail() and the ttm_lru_next_res()/prev_res() helpers.\nI:H - list_bulk_move_tail() and ttm_lru_bulk_move_pos_tail() write list pointers through the dangling cursor into freed memory. The commit message reports this showing up as list_del corruption, a write primitive usable against a sprayed object.\nA:H - The use-after-free crashes the kernel through list_del corruption, the dma_resv WARN in ttm_lru_bulk_move_add(), or a NULL dereference in ttm_resource_manager_next(). The reporter crashed 5 of 18 hibernation cycles."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-07T06:49:17.950Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/1169fe8c11ca45e3f91d59a73eb271d0ca8a7fb0"
        },
        {
          "url": "https://git.kernel.org/stable/c/3db7d7d583419f7b1f2e141e36418802dbb25cf8"
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      ],
      "title": "drm/ttm: fix swapped-out resources never leaving their bulk_move range",
      "x_generator": {
        "engine": "bippy-1.2.0"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98166",
    "datePublished": "2026-10-06T08:44:11.927Z",
    "dateReserved": "2026-09-25T10:25:14.321Z",
    "dateUpdated": "2026-10-07T06:49:17.950Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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GHSA-62XR-3QF5-9QPJ

CVE-2026-98166 (GCVE-0-2026-98166)

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