Bug 2414485 (CVE-2025-40166)

Summary: CVE-2025-40166 kernel: drm/xe/guc: Check GuC running state before deregistering exec queue
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel’s DRM Xe GuC driver (drm/xe/guc). If the GuC (Graphics microcontroller) has already stopped or disabled control-transport (CT) communication when the user calls exec_destroy() on an exec queue, the driver may not receive a response and thus fails to clean up the exec queue resources.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2025-11-12 11:02:50 UTC
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)