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CVE-2026-68239

Status: ReceivedUnscored—

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:

Technical details traces, logs and code from the original report
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>

CVSS

NVD hasn't assigned a CVSS score to this CVE (common since the April 2026 policy change).

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Linux — Linux KernelAI

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2026-68239",
  "cveTags": [],
  "metrics": {},
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "b63d715b8090aed48bdef5930625946fa4c0d324",
              "lessThan": "22aa7fb4e7d0b3ab41d1240ed743167980912970",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b63d715b8090aed48bdef5930625946fa4c0d324",
              "lessThan": "9ddaabf38f7a45b329e34358b98d2968d8649d21",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b63d715b8090aed48bdef5930625946fa4c0d324",
              "lessThan": "5b7b3b6595ee77d01c7463757baed114786094dd",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "drivers/gpu/drm/ttm/ttm_pool.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.15"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.15",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/gpu/drm/ttm/ttm_pool.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-10T13:20:12.273",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/22aa7fb4e7d0b3ab41d1240ed743167980912970",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/5b7b3b6595ee77d01c7463757baed114786094dd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9ddaabf38f7a45b329e34358b98d2968d8649d21",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "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 <TASK>\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 </TASK>"
    }
  ],
  "lastModified": "2026-08-17T05:18:26.187",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}