diff -up ./drivers/gpu/drm/drm_internal.h.rd ./drivers/gpu/drm/drm_internal.h
--- ./drivers/gpu/drm/drm_internal.h.rd	2026-02-01 08:09:53.000000000 +0900
+++ ./drivers/gpu/drm/drm_internal.h	2026-05-28 20:18:53.510188285 +0900
@@ -106,6 +106,10 @@ u64 drm_vblank_count(struct drm_device *
 /* drm_vblank_work.c */
 static inline void drm_vblank_flush_worker(struct drm_vblank_crtc *vblank)
 {
+	if (!vblank->worker) {
+		printk(KERN_WARNING "%s: vblank->worker NULL? returning\n", __func__);
+		return;
+	}
 	kthread_flush_worker(vblank->worker);
 }