In the Linux kernel, the following vulnerability has been resolved:

media: uvcvideo: Fix deadlock if uvc_status_stop is called from async_ctrl.work

If a UVC camera has an asynchronous control, uvc_status_stop may be
called from async_ctrl.work:

uvc_ctrl_status_event_work()
    uvc_ctrl_status_event()
        uvc_ctrl_clear_handle()
	    uvc_pm_put()
	        uvc_status_put()
		    uvc_status_stop()
		        cancel_work_sync()

This will cause a deadlock, since cancel_work_sync will wait for
uvc_ctrl_status_event_work to complete before returning.

Fix this by returning early from uvc_status_stop if we are currently in
the work function. flush_status now remains false until uvc_status_start
is called again, ensuring that uvc_ctrl_status_event_work won't resubmit
the URB.