if(is_debugging_ipc()){
KDEBUG(("IPC: SEND to %d from %d blocked\n",
dest, src->proc_nr));
}
// Otherwise, block current process and add it to
// head of sending queue of the destination.
src->state |= STATE_SENDING;
src->next_sender = pDest->sender_q;
pDest->sender_q = src;
This part could trigger undefined behavior if the sender is already receiving