drm/ttm: Drop tt->restore after successful restore

Summary

CVECVE-2026-89815
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-16 11:16:46 UTC
Updated2026-09-16 15:18:10 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: drm/ttm: Drop tt->restore after successful restore ttm_pool_restore_and_alloc() can successfully complete the restore process via ttm_pool_restore_commit(), but tt->restore is not dropped afterward. As a result, subsequent backup/restore flows observe what appears to be a completed restore, while in reality shmem handles are still installed in tt->pages, leading to the stack trace below. Fix this by freeing and dropping tt->restore in ttm_pool_restore_and_alloc() upon successful completion of the restore. 20545 [  309.784531] RIP: 0010:sg_alloc_append_table_from_pages+0x38c/0x490 20547 [  309.809570] RSP: 0018:ffffc9000623b838 EFLAGS: 00010206 20548 [  309.814827] RAX: 0000000000001000 RBX: ffff88816e42a160 RCX: 0000000000000000 20549 [  309.821986] RDX: 0000000000002000 RSI: 0000000000000003 RDI: 0000000000001000 20550 [  309.829147] RBP: ffff88816e42a168 R08: 0000000000000002 R09: 000000007ffff000 20551 [  309.836310] R10: ffffc9000623b928 R11: 0000000000000000 R12: 000000007ffff000 20552 [  309.843471] R13: ffff88815ba5a100 R14: 0000000000000000 R15: 0000000000000001 20553 [  309.850634] FS:  00007f9ff305e700(0000) GS:ffff888276c94000(0000) knlGS:0000000000000000 20554 [  309.858749] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 20555 [  309.864519] CR2: 00007f9fca701000 CR3: 00000001565e2005 CR4: 0000000008f70ef0 20556 [  309.871678] PKRU: 55555558 20557 [  309.874403] Call Trace: 20558 [  309.876866]  <TASK> 20559 [  309.878988]  sg_alloc_table_from_pages_segment+0x60/0x100 20560 [  309.884415]  ? ttm_resource_manager_usage+0x36/0x60 [ttm] 20561 [  309.889845]  ? xe_tt_map_sg+0x7d/0xd0 [xe] 20562 [  309.894045]  xe_tt_map_sg+0x7d/0xd0 [xe] 20563 [  309.898037]  xe_bo_move+0x927/0xaa0 [xe] 20564 [  309.902029]  ttm_bo_handle_move_mem+0xba/0x170 [ttm] 20565 [  309.907022]  ttm_bo_validate+0xbe/0x190 [ttm] 20566 [  309.911405]  xe_bo_validate+0x9a/0x120 [xe] 20567 [  309.915663]  xe_gpuvm_validate+0xd9/0x140 [xe] 20568 [  309.920206]  drm_gpuvm_validate+0x2f0/0x5b0 [drm_gpuvm] 20569 [  309.925459]  ? drm_exec_lock_obj+0x63/0x210 [drm_exec] 20570 [  309.930627]  xe_vm_validate_rebind+0x46/0xb0 [xe] 20571 [  309.935428]  xe_exec_fn+0x20/0x40 [xe] 20572 [  309.939249]  drm_gpuvm_exec_lock+0x78/0xc0 [drm_gpuvm] 20573 [  309.944410]  xe_validation_exec_lock+0x5a/0xa0 [xe] 20574 [  309.949385]  xe_exec_ioctl+0x806/0xc30 [xe] 20575 [  309.953639]  ? ttwu_queue_wakelist+0xd9/0xf0 20576 [  309.957935]  ? __pfx_xe_exec_fn+0x10/0x10 [xe] 20577 [  309.962449]  ? __wake_up_common+0x73/0xa0 20578 [  309.966482]  ? __pfx_xe_exec_ioctl+0x10/0x10 [xe] 20579 [  309.971263]  drm_ioctl_kernel+0xa3/0x100 20580 [  309.975209]  drm_ioctl+0x213/0x440 20581 [  309.978637]  ? __pfx_xe_exec_ioctl+0x10/0x10 [xe] 20582 [  309.983415]  xe_drm_ioctl+0x67/0xd0 [xe] 20583 [  309.987408]  __x64_sys_ioctl+0x7f/0xd0

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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


VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected b63d715b8090aed48bdef5930625946fa4c0d324 a46ab76b6cf5478e2ac7b942a377c7a1827b436a git Not specified
CNA Linux Linux affected b63d715b8090aed48bdef5930625946fa4c0d324 941ac10529b3be5965a88d432a161ab459672ba8 git Not specified
CNA Linux Linux affected 6.15 Not specified
CNA Linux Linux unaffected 6.15 semver Not specified
CNA Linux Linux unaffected 7.2.5 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/a46ab76b6cf5478e2ac7b942a377c7a1827b436a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/941ac10529b3be5965a88d432a161ab459672ba8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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