drm/vc4: Use managed KMS polling to fix UAF on unbind

Summary

In the Linux kernel, the following vulnerability has been resolved: drm/vc4: Use managed KMS polling to fix UAF on unbind vc4_kms_load() calls drm_kms_helper_poll_init() but the driver provides no matching drm_kms_helper_poll_fini(). The output poll work stays scheduled after unbind and runs on the freed drm_device: modprobe vc4; rmmod vc4; sleep 10 BUG: KASAN: slab-use-after-free in delayed_work_timer_fn BUG: KASAN: slab-use-after-free in drm_client_dev_hotplug [drm] Workqueue: events output_poll_execute [drm_kms_helper] Allocated by task 171: __devm_drm_dev_alloc Freed by task 262 (rmmod): drm_dev_put / component_del Use drmm_kms_helper_poll_init() so polling is finalized with the device, as other drivers do.

Timeline

1. Oct 6, 2026, 8:46 AM UTCCVE published
2. Oct 19, 2026, 9:17 AM UTCRecord last updated

Affected versions

• Linux Linux

  From c8b75bca92cbf064b9fa125fc74a85994452e935 · fixed in b6beee927e7f4e3142032ff91b2d0417cdddc0f6; From c8b75bca92cbf064b9fa125fc74a85994452e935 · fixed in cf0c4432bda37b02e7d430ff5017228ceb7caf0c; From c8b75bca92cbf064b9fa125fc74a85994452e935 · fixed in ee507691c18f9fee5d4751e295ab9a7ff31d59ae; From c8b75bca92cbf064b9fa125fc74a85994452e935 · fixed in 7f9780df677370a19b4ec9764f13b1b82073e0d9; From c8b75bca92cbf064b9fa125fc74a85994452e935 · fixed in 073a30d75f309812ed61af134f24ffef4107b13a

• Linux Linux

  4.4

• KernelLinux

  From 4.4.0 · fixed in 6.6.158; From 6.7.0 · fixed in 6.12.112; From 6.13.0 · fixed in 6.18.54; From 6.19.0 · fixed in 7.2.8

References 5