{"id":"CVE-2026-89815","summary":"drm/ttm: Drop tt-\u003erestore after successful restore","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/ttm: Drop tt-\u003erestore after successful restore\n\nttm_pool_restore_and_alloc() can successfully complete the restore\nprocess via ttm_pool_restore_commit(), but tt-\u003erestore is not dropped\nafterward. As a result, subsequent backup/restore flows observe what\nappears to be a completed restore, while in reality shmem handles are\nstill installed in tt-\u003epages, leading to the stack trace below.\n\nFix this by freeing and dropping tt-\u003erestore in\nttm_pool_restore_and_alloc() upon successful completion of the restore.\n\n20545 [  309.784531] RIP: 0010:sg_alloc_append_table_from_pages+0x38c/0x490\n20547 [  309.809570] RSP: 0018:ffffc9000623b838 EFLAGS: 00010206\n20548 [  309.814827] RAX: 0000000000001000 RBX: ffff88816e42a160 RCX: 0000000000000000\n20549 [  309.821986] RDX: 0000000000002000 RSI: 0000000000000003 RDI: 0000000000001000\n20550 [  309.829147] RBP: ffff88816e42a168 R08: 0000000000000002 R09: 000000007ffff000\n20551 [  309.836310] R10: ffffc9000623b928 R11: 0000000000000000 R12: 000000007ffff000\n20552 [  309.843471] R13: ffff88815ba5a100 R14: 0000000000000000 R15: 0000000000000001\n20553 [  309.850634] FS:  00007f9ff305e700(0000) GS:ffff888276c94000(0000) knlGS:0000000000000000\n20554 [  309.858749] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n20555 [  309.864519] CR2: 00007f9fca701000 CR3: 00000001565e2005 CR4: 0000000008f70ef0\n20556 [  309.871678] PKRU: 55555558\n20557 [  309.874403] Call Trace:\n20558 [  309.876866]  \u003cTASK\u003e\n20559 [  309.878988]  sg_alloc_table_from_pages_segment+0x60/0x100\n20560 [  309.884415]  ? ttm_resource_manager_usage+0x36/0x60 [ttm]\n20561 [  309.889845]  ? xe_tt_map_sg+0x7d/0xd0 [xe]\n20562 [  309.894045]  xe_tt_map_sg+0x7d/0xd0 [xe]\n20563 [  309.898037]  xe_bo_move+0x927/0xaa0 [xe]\n20564 [  309.902029]  ttm_bo_handle_move_mem+0xba/0x170 [ttm]\n20565 [  309.907022]  ttm_bo_validate+0xbe/0x190 [ttm]\n20566 [  309.911405]  xe_bo_validate+0x9a/0x120 [xe]\n20567 [  309.915663]  xe_gpuvm_validate+0xd9/0x140 [xe]\n20568 [  309.920206]  drm_gpuvm_validate+0x2f0/0x5b0 [drm_gpuvm]\n20569 [  309.925459]  ? drm_exec_lock_obj+0x63/0x210 [drm_exec]\n20570 [  309.930627]  xe_vm_validate_rebind+0x46/0xb0 [xe]\n20571 [  309.935428]  xe_exec_fn+0x20/0x40 [xe]\n20572 [  309.939249]  drm_gpuvm_exec_lock+0x78/0xc0 [drm_gpuvm]\n20573 [  309.944410]  xe_validation_exec_lock+0x5a/0xa0 [xe]\n20574 [  309.949385]  xe_exec_ioctl+0x806/0xc30 [xe]\n20575 [  309.953639]  ? ttwu_queue_wakelist+0xd9/0xf0\n20576 [  309.957935]  ? __pfx_xe_exec_fn+0x10/0x10 [xe]\n20577 [  309.962449]  ? __wake_up_common+0x73/0xa0\n20578 [  309.966482]  ? __pfx_xe_exec_ioctl+0x10/0x10 [xe]\n20579 [  309.971263]  drm_ioctl_kernel+0xa3/0x100\n20580 [  309.975209]  drm_ioctl+0x213/0x440\n20581 [  309.978637]  ? __pfx_xe_exec_ioctl+0x10/0x10 [xe]\n20582 [  309.983415]  xe_drm_ioctl+0x67/0xd0 [xe]\n20583 [  309.987408]  __x64_sys_ioctl+0x7f/0xd0","modified":"2026-09-18T03:48:32.940211198Z","published":"2026-09-16T10:30:48.133Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89815.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/941ac10529b3be5965a88d432a161ab459672ba8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a46ab76b6cf5478e2ac7b942a377c7a1827b436a"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89815.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89815"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"b63d715b8090aed48bdef5930625946fa4c0d324"},{"fixed":"a46ab76b6cf5478e2ac7b942a377c7a1827b436a"},{"fixed":"941ac10529b3be5965a88d432a161ab459672ba8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89815.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.15.0"},{"fixed":"7.2.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89815.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}