Re:GCC eBPF for Linux port has landed
by throwaway2048 on Monday September 09, 2019 @07:14PM
(#20923548)
This is trivial, when people talk about eBPF they are talking about the implementation, its like saying you could put lisp code in C, if only you modified the C compiler.
Re:GCC eBPF for Linux port has landed
by Spivak on Wednesday September 11, 2019 @03:30PM
(#20943796)
The implementation that exists in Linux is perfectly capable of running unbounded loops. But it runs your program through a function that rejects your program if it can't prove that it terminates.
The point being that you could rip the eBPF implementation out of the kernel, remove the verify check and have a very usable VM.
Here's a implementation that exists because of the GPL: https://github.com/iovisor/ubpf.
The verifier that exists in the Linux kernel works very hard to make sure that you are not allowed to load programs with unbounded loops but you most certainly can when those restrictions are lifted.