Re: Kernel 5.5.4 build fail for BPF-selftests with latest LLVM
From: Greg Kroah-Hartman
Date: Wed Feb 19 2020 - 08:29:02 EST
On Wed, Feb 19, 2020 at 01:30:12PM +0100, Jesper Dangaard Brouer wrote:
> Hi Andrii,
>
> Downloaded tarball for kernel release 5.5.4, and I cannot compile
> tools/testing/selftests/bpf/ with latest LLVM release version 9.
Is this something that recently broke? If so, what commit caused it?
And has llvm 9 always worked here?
> Looking closer at the build error messages, I can see that this is
> caused by using LLVM features that (I assume) will be avail in release
> 10. I find it very strange that we can release a kernel that have build
> dependencies on a unreleased version of LLVM.
Is this the first time you have tried using llvm to build a kernel?
This isn't a new thing :)
> I love the new LLVM BTF features, but we cannot break users/CI-systems
> that wants to run the BPF-selftests.
Is this a regression from older kernels?
And does gcc work?
thanks,
greg k-h