In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: aspeed-vhub: cancel wake work on device removal
wake_work is armed from the gadget .wakeup callback to resume suspended
downstream ports, and it is never cancelled in ast_vhub_remove(), so a
work item queued before or during removal can run after devm has freed
vhub and its ports, a use-after-free.
Cancelling the work alone is not sufficient: usb_gadget_wakeup() takes
no lock and the unbind path never clears wakeup_en, so a remote-wakeup
request in flight on another CPU can re-arm the work after the cancel
and before vhub is freed.
ast_vhub_del_dev() already clears d->registered under vhub->lock before
unregistering the gadget. Refuse the wakeup in ast_vhub_udc_wakeup()
once d->registered is clear: the check and the schedule_work() are then
atomic against the unbind, so a wakeup that passed before the flag was
cleared is drained by the cancel_work_sync() after the del_dev loop,
and one that arrives later returns without arming. Also move INIT_WORK()
to the top of ast_vhub_probe(), since the probe error path reuses
ast_vhub_remove() and would otherwise cancel a never-initialized work
item.
This issue was found by an in-house static analysis tool.
