kernel thread priority over user thread

Hello, I am trying to understand if kernel thread are always higher priority then user thread. Say, a kernel thread (created with kthread_create with SCHED_FIFO and given priority x), and user thread (created with pthread_create was created with SCHED_FIFO and given priority y), and priority of pthread is higher than kthread, would still the kernel thread get into scheduler before the user thread ? How is the scheduler decides which get first into the running state ? Regards, Ran