GHSA-W5C5-94W7-PXG8
Vulnerability from github – Published: 2026-09-16 12:30 – Updated: 2026-09-21 15:31In 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] 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": [],
"aliases": [
"CVE-2026-89815"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-16T11:16:46Z",
"severity": "HIGH"
},
"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 [\u00a0 309.784531] RIP: 0010:sg_alloc_append_table_from_pages+0x38c/0x490\n20547 [\u00a0 309.809570] RSP: 0018:ffffc9000623b838 EFLAGS: 00010206\n20548 [\u00a0 309.814827] RAX: 0000000000001000 RBX: ffff88816e42a160 RCX: 0000000000000000\n20549 [\u00a0 309.821986] RDX: 0000000000002000 RSI: 0000000000000003 RDI: 0000000000001000\n20550 [\u00a0 309.829147] RBP: ffff88816e42a168 R08: 0000000000000002 R09: 000000007ffff000\n20551 [\u00a0 309.836310] R10: ffffc9000623b928 R11: 0000000000000000 R12: 000000007ffff000\n20552 [\u00a0 309.843471] R13: ffff88815ba5a100 R14: 0000000000000000 R15: 0000000000000001\n20553 [\u00a0 309.850634] FS:\u00a0 00007f9ff305e700(0000) GS:ffff888276c94000(0000) knlGS:0000000000000000\n20554 [\u00a0 309.858749] CS:\u00a0 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n20555 [\u00a0 309.864519] CR2: 00007f9fca701000 CR3: 00000001565e2005 CR4: 0000000008f70ef0\n20556 [\u00a0 309.871678] PKRU: 55555558\n20557 [\u00a0 309.874403] Call Trace:\n20558 [\u00a0 309.876866]\u00a0 \u003cTASK\u003e\n20559 [\u00a0 309.878988]\u00a0 sg_alloc_table_from_pages_segment+0x60/0x100\n20560 [\u00a0 309.884415]\u00a0 ? ttm_resource_manager_usage+0x36/0x60 [ttm]\n20561 [\u00a0 309.889845]\u00a0 ? xe_tt_map_sg+0x7d/0xd0 [xe]\n20562 [\u00a0 309.894045]\u00a0 xe_tt_map_sg+0x7d/0xd0 [xe]\n20563 [\u00a0 309.898037]\u00a0 xe_bo_move+0x927/0xaa0 [xe]\n20564 [\u00a0 309.902029]\u00a0 ttm_bo_handle_move_mem+0xba/0x170 [ttm]\n20565 [\u00a0 309.907022]\u00a0 ttm_bo_validate+0xbe/0x190 [ttm]\n20566 [\u00a0 309.911405]\u00a0 xe_bo_validate+0x9a/0x120 [xe]\n20567 [\u00a0 309.915663]\u00a0 xe_gpuvm_validate+0xd9/0x140 [xe]\n20568 [\u00a0 309.920206]\u00a0 drm_gpuvm_validate+0x2f0/0x5b0 [drm_gpuvm]\n20569 [\u00a0 309.925459]\u00a0 ? drm_exec_lock_obj+0x63/0x210 [drm_exec]\n20570 [\u00a0 309.930627]\u00a0 xe_vm_validate_rebind+0x46/0xb0 [xe]\n20571 [\u00a0 309.935428]\u00a0 xe_exec_fn+0x20/0x40 [xe]\n20572 [\u00a0 309.939249]\u00a0 drm_gpuvm_exec_lock+0x78/0xc0 [drm_gpuvm]\n20573 [\u00a0 309.944410]\u00a0 xe_validation_exec_lock+0x5a/0xa0 [xe]\n20574 [\u00a0 309.949385]\u00a0 xe_exec_ioctl+0x806/0xc30 [xe]\n20575 [\u00a0 309.953639]\u00a0 ? ttwu_queue_wakelist+0xd9/0xf0\n20576 [\u00a0 309.957935]\u00a0 ? __pfx_xe_exec_fn+0x10/0x10 [xe]\n20577 [\u00a0 309.962449]\u00a0 ? __wake_up_common+0x73/0xa0\n20578 [\u00a0 309.966482]\u00a0 ? __pfx_xe_exec_ioctl+0x10/0x10 [xe]\n20579 [\u00a0 309.971263]\u00a0 drm_ioctl_kernel+0xa3/0x100\n20580 [\u00a0 309.975209]\u00a0 drm_ioctl+0x213/0x440\n20581 [\u00a0 309.978637]\u00a0 ? __pfx_xe_exec_ioctl+0x10/0x10 [xe]\n20582 [\u00a0 309.983415]\u00a0 xe_drm_ioctl+0x67/0xd0 [xe]\n20583 [\u00a0 309.987408]\u00a0 __x64_sys_ioctl+0x7f/0xd0",
"id": "GHSA-w5c5-94w7-pxg8",
"modified": "2026-09-21T15:31:43Z",
"published": "2026-09-16T12:30:37Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89815"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/329ddc5d438f991f49e4fd24c704d1c7288d5e03"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/941ac10529b3be5965a88d432a161ab459672ba8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a46ab76b6cf5478e2ac7b942a377c7a1827b436a"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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