Re: [PATCH] BPF: Disable on PREEMPT_RT

David Miller
2019-10-17T22:13:39Z

From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 17 Oct 2019 23:54:07 +0200 (CEST)

> Clark might have some insight from the product side for you how much that
> impacts usability.

You won't even be able to load systemd, it uses bpf.

We're moving to the point where even LSM modules will be implemented in bpf.
IR drivers require bpf:

https://lwn.net/Articles/759188/

I understand the problems, and realize they are non-trivial, but this hammer
is really destructive on a fundamental level.

To a certain extent, those who insert bpf programs are explicitly
changing the kernel so really the onus is on them to make sure the
programs complete in time which is not only finite (which is
guaranteed by BPF) but also within the RT constraints.