FKIE_CVE-2026-68266

Vulnerability from fkie_nvd - Published: 2026-08-10 13:20 - Updated: 2026-08-17 05:18
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/xe: Hold a dma-buf reference for imported BOs An imported dma-buf BO is created as a ttm_bo_type_sg BO whose reservation object is the exporter's dma_buf->resv. The importer, however, only takes a dma-buf reference after a successful dma_buf_dynamic_attach(). Until then nothing keeps the exporter alive, so if the exporter is freed while the BO still references its resv, a later access to that resv is a use-after-free: Oops: general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b9c Workqueue: ttm ttm_bo_delayed_delete [ttm] RIP: 0010:mutex_can_spin_on_owner+0x3f/0xc0 This can be reached on two paths: - dma_buf_dynamic_attach() fails, or - ttm_bo_init_reserved() fails during BO creation. In both cases the BO already has bo->base.resv pointing at the exporter resv, and sg BOs are always torn down via ttm_bo_delayed_delete(), which locks bo->base.resv asynchronously - potentially after the exporter has been freed. Take the dma-buf reference in xe_bo_init_locked(), before ttm_bo_init_reserved(), so it also covers a creation failure there, and release it in xe_ttm_bo_destroy(). The reference is held for the whole BO lifetime, keeping the shared resv alive on every path. v2: - Reworked the fix to avoid creating the imported sg BO before dma_buf_dynamic_attach() succeeds. - Attach with importer_priv == NULL and make invalidate_mappings ignore incomplete imports. v3: - Dropped the xe-side reordering approach since importer_priv must be valid when dma_buf_dynamic_attach() publishes the attachment. - Per Christian's suggestion on the v1 thread, keyed the check on import_attach rather than removing the sg guard entirely. - Fixes both xe and amdgpu in a single TTM patch. v4: - Moved import_attach check to after dma_resv_copy_fences() so fences are copied before returning for successful imports (Thomas). - Removed exporter-alive claim from commit message (Thomas). v5: - Add drm/xe patch to keep imported sg BOs off the LRU before attach succeeds; the TTM fix alone is not sufficient for xe if the BO is already LRU-visible. (Thomas) v4 patch: https://patchwork.freedesktop.org/patch/736663/?series=169129&rev=2 - Patch 1 (drm/ttm) carries Christian's Reviewed-by from v4. v6: - Reworked the fix based on Thomas' suggestion. Instead of the TTM resv individualization (v1-v5) plus the xe off-LRU/placement handling (v5), just hold a dma-buf reference for the imported BO lifetime so the shared resv can never be freed while the BO still references it. Single xe patch, no TTM change. (Thomas) - Take the reference in xe_bo_init_locked() before ttm_bo_init_reserved() so a TTM creation failure is covered too (Thomas). - Dropped the v5 series (drm/ttm + drm/xe off-LRU); the off-LRU approach also regressed in CI BAT via ttm_bo_pipeline_gutting() creating a ghost BO that outlived the exporter. Link to v5: https://patchwork.freedesktop.org/series/169984/ v7: - Move changelog above --- so it stays in the commit message. - Reorder changelog entries oldest-to-newest. (Thomas) (cherry picked from commit 3516f3fae6be35642f8f06f8a218da6425c0306a)
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/62775525a27c3b0d56382e08ba81ee2d322058b6
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ba8c4cbb31c6f81fa5b12d6e28f1f706040aff48
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c1954c66662de477a8f4309335b775f7b07bd28b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c22d65d62b3318e237c0e5b1177d90ab83d9fe06
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/xe/xe_bo.c",
            "drivers/gpu/drm/xe/xe_bo.h",
            "drivers/gpu/drm/xe/xe_bo_types.h",
            "drivers/gpu/drm/xe/xe_dma_buf.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "c22d65d62b3318e237c0e5b1177d90ab83d9fe06",
              "status": "affected",
              "version": "dd08ebf6c3525a7ea2186e636df064ea47281987",
              "versionType": "git"
            },
            {
              "lessThan": "c1954c66662de477a8f4309335b775f7b07bd28b",
              "status": "affected",
              "version": "dd08ebf6c3525a7ea2186e636df064ea47281987",
              "versionType": "git"
            },
            {
              "lessThan": "ba8c4cbb31c6f81fa5b12d6e28f1f706040aff48",
              "status": "affected",
              "version": "dd08ebf6c3525a7ea2186e636df064ea47281987",
              "versionType": "git"
            },
            {
              "lessThan": "62775525a27c3b0d56382e08ba81ee2d322058b6",
              "status": "affected",
              "version": "dd08ebf6c3525a7ea2186e636df064ea47281987",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/xe/xe_bo.c",
            "drivers/gpu/drm/xe/xe_bo.h",
            "drivers/gpu/drm/xe/xe_bo_types.h",
            "drivers/gpu/drm/xe/xe_dma_buf.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.8"
            },
            {
              "lessThan": "6.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.103",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/xe: Hold a dma-buf reference for imported BOs\n\nAn imported dma-buf BO is created as a ttm_bo_type_sg BO whose\nreservation object is the exporter\u0027s dma_buf-\u003eresv. The importer,\nhowever, only takes a dma-buf reference after a successful\ndma_buf_dynamic_attach(). Until then nothing keeps the exporter alive,\nso if the exporter is freed while the BO still references its resv, a\nlater access to that resv is a use-after-free:\n\n  Oops: general protection fault, probably for non-canonical address\n        0x6b6b6b6b6b6b6b9c\n  Workqueue: ttm ttm_bo_delayed_delete [ttm]\n  RIP: 0010:mutex_can_spin_on_owner+0x3f/0xc0\n\nThis can be reached on two paths:\n\n - dma_buf_dynamic_attach() fails, or\n - ttm_bo_init_reserved() fails during BO creation.\n\nIn both cases the BO already has bo-\u003ebase.resv pointing at the exporter\nresv, and sg BOs are always torn down via ttm_bo_delayed_delete(), which\nlocks bo-\u003ebase.resv asynchronously - potentially after the exporter has\nbeen freed.\n\nTake the dma-buf reference in xe_bo_init_locked(), before\nttm_bo_init_reserved(), so it also covers a creation failure there, and\nrelease it in xe_ttm_bo_destroy(). The reference is held for the whole\nBO lifetime, keeping the shared resv alive on every path.\n\nv2:\n  - Reworked the fix to avoid creating the imported sg BO before\n    dma_buf_dynamic_attach() succeeds.\n  - Attach with importer_priv == NULL and make invalidate_mappings ignore\n    incomplete imports.\n\nv3:\n  - Dropped the xe-side reordering approach since importer_priv must be\n    valid when dma_buf_dynamic_attach() publishes the attachment.\n  - Per Christian\u0027s suggestion on the v1 thread, keyed the check on\n    import_attach rather than removing the sg guard entirely.\n  - Fixes both xe and amdgpu in a single TTM patch.\n\nv4:\n  - Moved import_attach check to after dma_resv_copy_fences() so fences\n    are copied before returning for successful imports (Thomas).\n  - Removed exporter-alive claim from commit message (Thomas).\n\nv5:\n  - Add drm/xe patch to keep imported sg BOs off the LRU before attach\n    succeeds; the TTM fix alone is not sufficient for xe if the BO is\n    already LRU-visible. (Thomas)\n    v4 patch:\n    https://patchwork.freedesktop.org/patch/736663/?series=169129\u0026rev=2\n  - Patch 1 (drm/ttm) carries Christian\u0027s Reviewed-by from v4.\n\nv6:\n  - Reworked the fix based on Thomas\u0027 suggestion. Instead of the TTM resv\n    individualization (v1-v5) plus the xe off-LRU/placement handling (v5),\n    just hold a dma-buf reference for the imported BO lifetime so the\n    shared resv can never be freed while the BO still references it.\n    Single xe patch, no TTM change. (Thomas)\n  - Take the reference in xe_bo_init_locked() before ttm_bo_init_reserved()\n    so a TTM creation failure is covered too (Thomas).\n  - Dropped the v5 series (drm/ttm + drm/xe off-LRU); the off-LRU approach\n    also regressed in CI BAT via ttm_bo_pipeline_gutting() creating a ghost\n    BO that outlived the exporter.\n    Link to v5: https://patchwork.freedesktop.org/series/169984/\n\nv7:\n  - Move changelog above --- so it stays in the commit message.\n  - Reorder changelog entries oldest-to-newest. (Thomas)\n\n(cherry picked from commit 3516f3fae6be35642f8f06f8a218da6425c0306a)"
    }
  ],
  "id": "CVE-2026-68266",
  "lastModified": "2026-08-17T05:18:29.100",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-10T13:20:15.493",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/62775525a27c3b0d56382e08ba81ee2d322058b6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ba8c4cbb31c6f81fa5b12d6e28f1f706040aff48"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c1954c66662de477a8f4309335b775f7b07bd28b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c22d65d62b3318e237c0e5b1177d90ab83d9fe06"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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