CVE-2026-89816: drm: Fix drm_crtc_commit leak if signaled when PAGE_FLIP_EVENT is used

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-16 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: drm: Fix drm_crtc_commit leak if signaled when PAGE_FLIP_EVENT is used Commit 1c6ceeee6ebb ("drm/atomic: Fix memleak on ERESTARTSYS during non-blocking commits") fixed a very similar issue when the event was allocated by drm_atomic_helper_setup_commit() itself. However, if the event is allocated in prepare_signaling(), it will also be set to NULL in complete_signaling(), which prevents drm_crtc_commit from being put in __drm_atomic_helper_crtc_destroy_state(). Dropping the reference when the event is set to NULL at complete_signaling() fixes the leak. The leak can be reproduced by sending a signal to the thread using DRM_MODE_PAGE_FLIP_EVENT and using a sw_sync fence to cause the atomic ioctl to block at drm_atomic_helper_wait_for_fences(). It happened both with amdgpu and vkms.

Affected products

Linux kernel: from 4.9.19 before 4.10; from 4.10.7 before 4.11; 4.11 — fixed in 4.10, 4.11, 7.3

How to fix

Upgrade to a fixed version: Linux kernel 4.10, 4.11, 7.3. Check the vendor advisory for mitigations.

References

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