Medium · published September 15, 2026
The ITE it82xx2 USB device-controller driver initialized its bus-suspend detection work with k_work_init_delayable(&priv->suspended_work, suspended_handler) inside it82xx2_enable() (the driver's .enable op) in drivers/usb/udc/udc_it82xx2.c. This work item is scheduled essentially continuously while the USB bus is active: the interrupt handler reschedules it on every SOF frame and suspended_handler() reschedules itself, so its timeout node is normally linked in the kernel timeout list / a workqueue pending queue.
k_work_init_delayable() (kernel/work.c) unconditionally overwrites the entire k_work_delayable structure, including its timeout and queue linkage, with no busy check. Because it82xx2_disable() does not cancel the work, a normal disable-then-enable cycle re-runs api->enable() (udc_enable() only rejects a redundant enable, not a re-enable after disable) and re-initializes the still-pending work in place, corrupting the kernel timeout/workqueue linked lists and causing a kernel panic.
An external USB host — for example a host performing USB DFU detach (dfu-util --detach) or forcing repeated attach/reset/re-enumeration — drives the udc_disable()/udc_enable() transitions and controls suspend/resume timing, so it can arrange for the suspend work to be pending across a re-enable. This yields an unauthenticated denial of service (kernel panic) reachable across the USB boundary from a removable, physically-connected host, with no confidentiality or integrity impact demonstrated.
The fix moves the k_work_init_delayable() call into the one-time preinit function so the work is initialized exactly once, eliminating the re-initialization of an in-use item.