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CVE-2026-68239

drm/ttm: Account for NULL and handle pages in ttm_pool_backup

N/A
Published: August 10, 2026 at 12:01 PM UTC
Updated: August 17, 2026 at 05:18 AM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
N/A
Exploit prediction
EPSS 0.2%

Description

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>

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Linux Kernel· Linux
95%
6.15 ≤ v < 6.18.426.15 ≤ v < 7.1.66.15 ≤ v < 7.26.15b63d715b8090aed48bdef5930625946fa4c0d324
Vendor states this is fixed in 22aa7fb4e7d0b3ab41d1240ed743167980912970 (fixed)
Vendor states this is fixed in 5b7b3b6595ee77d01c7463757baed114786094dd (fixed)
Vendor states this is fixed in 9ddaabf38f7a45b329e34358b98d2968d8649d21 (fixed)
Vendor states this is fixed in 6.15 (unaffected)
Vendor states this is fixed in 6.18.42 (unaffected)
Vendor states this is fixed in 7.1.6 (unaffected)
Vendor states this is fixed in 7.2 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (3)

Source: cverecord
https://git.kernel.org/stable/c/22aa7fb4e7d0b3ab41d1240ed743167980912970
Source: cverecord
https://git.kernel.org/stable/c/9ddaabf38f7a45b329e34358b98d2968d8649d21
Source: cverecord
https://git.kernel.org/stable/c/5b7b3b6595ee77d01c7463757baed114786094dd

Quick Info

StatusRECEIVED

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