CVE-2026-89816In 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.