Re: [PATCH bpf v2 2/2] selftests/bpf: Add socket filter attach test

[Puranjay Mohan]

On Thu, Aug 14, 2025 at 2:35 AM Eduard Zingerman <eddyz87@xxxxxxxxx> wrote:
>
> On Wed, 2025-08-13 at 23:29 +0800, KaFai Wan wrote:
> > This test verifies socket filter attachment functionality on architectures
> > supporting either BPF JIT compilation or the interpreter.
> >
> > It specifically validates the fallback to interpreter behavior when JIT fails,
> > particularly targeting ARMv6 devices with the following configuration:
> >   # CONFIG_BPF_JIT_ALWAYS_ON is not set
> >   CONFIG_BPF_JIT_DEFAULT_ON=y
> >
> > Signed-off-by: KaFai Wan <kafai.wan@xxxxxxxxx>
> > ---
>
> This test should not be landed as-is, first let's do an analysis for
> why the program fails to jit compile on arm.
>
> I modified kernel to dump BPF program before jit attempt, but don't
> see anything obviously wrong with it.  The patch to get disassembly
> and disassembly itself with resolved kallsyms are attached.
>
> Can someone with access to ARM vm/machine take a looks at this?
> Puranjay, Xu, would you have some time?

Hi Eduard,
Thanks for the email, I will look into it.

Let me try to boot a kernel on ARMv6 qemu and reproduce this.

Thanks,
Puranjay