Parent PID for kthreads?

Hi all, I'm looking for a way to determine the PID of the process on which kthread_create is invoked to spawn a new kthread. The newly created kthreads all show current->parent->pid == 2, which I understand corresponds to kthreadd. current->tgid doesn't seem to be set to the main process' PID either. Is there a way to determine this from within the kthread? Thanks!