CVE-2026-99090
Received Received - Intake

Race Condition in AMDGPU Kernel Leads to Lockdep Warning

Publication date: 2026-10-26

Last updated on: 2026-10-26

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: serialize vblank counter reads against GPU reset The vblank counter callback reads display registers and scanout position without holding reset_domain->sem. During GPU recovery, display commit work can call the callback while reset owns the semaphore for writing. The hardware access then triggers the lockdep_assert_held() in amdgpu_device_skip_hw_access() and sets TAINT_WARN when lockdep is enabled. Try to acquire the reset semaphore for reading before accessing the hardware, and hold it across the counter and scanout-position reads. If reset is already in progress, return DRM's cached software vblank count instead. This avoids blocking behind reset and avoids accessing display hardware while it is being reset. The cached count is less accurate than the hardware count, but is used only when reset prevents a safe hardware read. This addresses the reset-time warning from this vblank path; it does not suppress or fix unrelated lockdep warnings. (cherry picked from commit 51a4359f7431a4be5e42803c8bdaf7e0e5be2934)

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Meta Information

Published
2026-10-26
Last Modified
2026-10-26
Generated
2026-10-26
AI Q&A
2026-10-26
EPSS Evaluated
N/A
NVD
CVE-2026-99090
EUVD
EUVD-2026-109896

Affected Vendors & Products

Showing 9 associated CPEs
Vendor Product Version / Range
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Linux Linux 0
Linux Linux 0
Linux Linux 0
Linux Linux 0

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Exploitability

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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a race condition in the AMD GPU driver where the vblank counter reads display registers without proper synchronization during GPU recovery. This can trigger lockdep warnings and set TAINT_WARN when lockdep is enabled, potentially causing system instability.

Detection Guidance

This vulnerability is specific to the Linux kernel's AMD GPU driver and may trigger lockdep warnings during GPU recovery. Detection typically involves monitoring kernel logs for lockdep_assert_held() warnings or TAINT_WARN messages related to amdgpu_device_skip_hw_access(). Check dmesg or journalctl for errors like 'TAINT_WARN' or 'lockdep' after GPU reset events.

Impact Analysis

The vulnerability may cause system warnings or instability during GPU operations, particularly when the GPU is being reset or recovered. It could lead to display issues or performance problems in systems using AMD GPUs.

Mitigation Strategies

Apply the kernel patch that serializes vblank counter reads against GPU reset. Update to a kernel version containing the fix (e.g., commit 51a4359f7431a4be5e42803c8bdaf7e0e5be2934). If immediate patching is not possible, avoid triggering GPU resets during active display operations to reduce exposure.

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