CVE-2026-89815
drm/ttm: Drop tt->restore after successful restore
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Description
In 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
Affected
Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.
Remediation
No guide yetNo remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.
References (3)
CVSS
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