Re: [PATCH 10/11] sched_ext: scx_qmap: Add proxy execution support

From: Andrea Righi

Date: Sat Jul 18 2026 - 04:24:48 EST


On Fri, Jul 17, 2026 at 11:04:16PM -0700, John Stultz wrote:
> On Fri, Jul 17, 2026 at 10:47 PM Andrea Righi <arighi@xxxxxxxxxx> wrote:
> > This looks like something related to BPF arena pointers and incorrectly
> > generated BPF code (the other schedulers don't use BPF arenas, so that'd explain
> > why you only see this with scx_qmap).
> >
> > Which version of clang are you using?
>
> Debian clang version 19.1.7 (3+b1)
>
> Running in a debian 13 vm. Though I'm using gcc normally for my
> builds (but I see the tools/sched_ext/ build does use clang explicitly
> for some things).

Yeah, we explicitly use clang to build BPF code. I'm on CachyOS, which ships
clang 22.1.8. In theory clang-19 should be enough... if you can mess up the VM
maybe give it a try with clang 20? From the dump it really looks like the
compiler failed to generate proper BPF code for arenas.

Thanks,
-Andrea