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