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Fencer Vulns
high 7.8

CVE-2026-89815 json

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

published 2026-09-16 54 d ago modified 2026-10-19 21 d ago also EUVD-2026-80415

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 6%
public exploits
0
none known

Summary

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

Patch / fix

  • Linux Linux 6.18.53, 7.2.5, 7.3
  • linux Debian 14 7.2.6-1

debian advisories DEBIAN-CVE-2026-89815

  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-ibm Ubuntu 26.04 LTS 7.0.0-1017.17
  • linux-riscv Ubuntu 26.04 LTS 7.0.0-42.42.1
  • linux-oracle Ubuntu 26.04 LTS 7.0.0-1015.16
  • linux-hwe-7.0 Ubuntu 24.04 LTS 7.0.0-42.42~24.04.1
  • linux-oem-7.0 Ubuntu 26.04 LTS 7.0.0-1017.17

ubuntu advisories UBUNTU-CVE-2026-89815

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-source openSUSE Tumbleweed 7.2.7-1.1

opensuse advisories openSUSE-SU-2026:11880-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-89815 updated cvss 5.5

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

  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 more Red Hat Enterprise Linux 10 kernel Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-selftests-internal Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.