CVE-2026-68239 (GCVE-0-2026-68239)
Vulnerability from cvelistv5
Published
2026-08-10 12:01
Modified
2026-08-17 05:01
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/ttm: Account for NULL and handle pages in ttm_pool_backup Pages in ttm_pool_backup can be NULL or backup handles (ttm_backup_page_ptr_is_handle()), neither of which can be passed to set_pages_array_wb() or freed. Add a dedicated WB pass before the dma/purge loop that walks allocations using the same i += num_pages stride, skipping NULL and handle entries, and calls set_pages_array_wb() once per contiguous run of real pages. Apply the same NULL/handle guard to the dma/purge loop. Fixes the following oops: Oops: general protection fault, kernel NULL pointer dereference 0x0: 0000 [#1] SMP NOPTI RIP: 0010:__cpa_process_fault+0xf8/0x770 RSP: 0018:ffffc90000a87718 EFLAGS: 00010287 RAX: 0000000000000000 RBX: ffffc90000a87868 RCX: 0000000000000000 RDX: 0000000000001000 RSI: 0005088000000000 RDI: ffffffff827c5f34 RBP: 0005088000000000 R08: ffffc90000a877cb R09: ffffc90000a877d0 R10: 0000000000000000 R11: 000000000000001b R12: 000ffffffffff000 R13: ffffc90000a87868 R14: ffffc90000a87868 R15: ffff88815b882ae0 FS: 0000000000000000(0000) GS:ffff8884ec840000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f930b844000 CR3: 000000000262e003 CR4: 0000000008f70ef0 PKRU: 55555554 Call Trace: <TASK> __change_page_attr_set_clr+0x989/0xe90 ? __purge_vmap_area_lazy+0x6c/0x3a0 ? _vm_unmap_aliases+0x250/0x2a0 set_pages_array_wb+0x7f/0x120 ttm_pool_backup+0x4c9/0x5b0 [ttm] ? dma_resv_wait_timeout+0x3b/0xf0 ttm_tt_backup+0x32/0x60 [ttm] ttm_bo_shrink+0x66/0x110 [ttm] xe_bo_shrink_purge+0x12b/0x1b0 [xe] xe_bo_shrink+0xbb/0x270 [xe] __xe_shrinker_walk+0xf7/0x160 [xe] xe_shrinker_walk+0x9d/0xc0 [xe] xe_shrinker_scan+0x11f/0x210 [xe] do_shrink_slab+0x13b/0x270 shrink_slab+0xf1/0x400 shrink_node+0x352/0x8a0 balance_pgdat+0x32c/0x700 kswapd+0x205/0x2f0 ? __pfx_autoremove_wake_function+0x10/0x10 ? __pfx_kswapd+0x10/0x10 kthread+0xd1/0x110 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x1b1/0x200 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK>
References
Impacted products
Vendor Product Version
Linux Linux Version: b63d715b8090aed48bdef5930625946fa4c0d324
Version: b63d715b8090aed48bdef5930625946fa4c0d324
Version: b63d715b8090aed48bdef5930625946fa4c0d324
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/ttm/ttm_pool.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "22aa7fb4e7d0b3ab41d1240ed743167980912970",
              "status": "affected",
              "version": "b63d715b8090aed48bdef5930625946fa4c0d324",
              "versionType": "git"
            },
            {
              "lessThan": "9ddaabf38f7a45b329e34358b98d2968d8649d21",
              "status": "affected",
              "version": "b63d715b8090aed48bdef5930625946fa4c0d324",
              "versionType": "git"
            },
            {
              "lessThan": "5b7b3b6595ee77d01c7463757baed114786094dd",
              "status": "affected",
              "version": "b63d715b8090aed48bdef5930625946fa4c0d324",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/ttm/ttm_pool.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.15"
            },
            {
              "lessThan": "6.15",
              "status": "unaffected",
              "version": "0",
              "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"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.42",
                  "versionStartIncluding": "6.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.6",
                  "versionStartIncluding": "6.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.15",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/ttm: Account for NULL and handle pages in ttm_pool_backup\n\nPages in ttm_pool_backup can be NULL or backup handles\n(ttm_backup_page_ptr_is_handle()), neither of which can be passed to\nset_pages_array_wb() or freed. Add a dedicated WB pass before the\ndma/purge loop that walks allocations using the same i += num_pages\nstride, skipping NULL and handle entries, and calls set_pages_array_wb()\nonce per contiguous run of real pages. Apply the same NULL/handle guard\nto the dma/purge loop.\n\nFixes the following oops:\n\nOops: general protection fault, kernel NULL pointer dereference 0x0: 0000 [#1] SMP NOPTI\nRIP: 0010:__cpa_process_fault+0xf8/0x770\nRSP: 0018:ffffc90000a87718 EFLAGS: 00010287\nRAX: 0000000000000000 RBX: ffffc90000a87868 RCX: 0000000000000000\nRDX: 0000000000001000 RSI: 0005088000000000 RDI: ffffffff827c5f34\nRBP: 0005088000000000 R08: ffffc90000a877cb R09: ffffc90000a877d0\nR10: 0000000000000000 R11: 000000000000001b R12: 000ffffffffff000\nR13: ffffc90000a87868 R14: ffffc90000a87868 R15: ffff88815b882ae0\nFS:  0000000000000000(0000) GS:ffff8884ec840000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00007f930b844000 CR3: 000000000262e003 CR4: 0000000008f70ef0\nPKRU: 55555554\nCall Trace:\n \u003cTASK\u003e\n __change_page_attr_set_clr+0x989/0xe90\n ? __purge_vmap_area_lazy+0x6c/0x3a0\n ? _vm_unmap_aliases+0x250/0x2a0\n set_pages_array_wb+0x7f/0x120\n ttm_pool_backup+0x4c9/0x5b0 [ttm]\n ? dma_resv_wait_timeout+0x3b/0xf0\n ttm_tt_backup+0x32/0x60 [ttm]\n ttm_bo_shrink+0x66/0x110 [ttm]\n xe_bo_shrink_purge+0x12b/0x1b0 [xe]\n xe_bo_shrink+0xbb/0x270 [xe]\n __xe_shrinker_walk+0xf7/0x160 [xe]\n xe_shrinker_walk+0x9d/0xc0 [xe]\n xe_shrinker_scan+0x11f/0x210 [xe]\n do_shrink_slab+0x13b/0x270\n shrink_slab+0xf1/0x400\n shrink_node+0x352/0x8a0\n balance_pgdat+0x32c/0x700\n kswapd+0x205/0x2f0\n ? __pfx_autoremove_wake_function+0x10/0x10\n ? __pfx_kswapd+0x10/0x10\n kthread+0xd1/0x110\n ? __pfx_kthread+0x10/0x10\n ret_from_fork+0x1b1/0x200\n ? __pfx_kthread+0x10/0x10\n ret_from_fork_asm+0x1a/0x30\n \u003c/TASK\u003e"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:01:28.470Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/22aa7fb4e7d0b3ab41d1240ed743167980912970"
        },
        {
          "url": "https://git.kernel.org/stable/c/9ddaabf38f7a45b329e34358b98d2968d8649d21"
        },
        {
          "url": "https://git.kernel.org/stable/c/5b7b3b6595ee77d01c7463757baed114786094dd"
        }
      ],
      "title": "drm/ttm: Account for NULL and handle pages in ttm_pool_backup",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68239",
    "datePublished": "2026-08-10T12:01:04.297Z",
    "dateReserved": "2026-07-30T09:28:09.376Z",
    "dateUpdated": "2026-08-17T05:01:28.470Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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