Re: [PATCH bpf-next v2 2/2] selftests/bpf: Add case to test bpf_in_interrupt kfunc

[Eduard Zingerman <eddyz87@gmail.com>]

On Tue, 2025-08-26 at 11:05 +0800, Leon Hwang wrote:

[...]

> > > diff --git a/tools/testing/selftests/bpf/progs/irq.c b/tools/testing/selftests/bpf/progs/irq.c
> > > index 74d912b22de90..65a796fd1d615 100644
> > > --- a/tools/testing/selftests/bpf/progs/irq.c
> > > +++ b/tools/testing/selftests/bpf/progs/irq.c
> > > @@ -563,4 +563,11 @@ int irq_wrong_kfunc_class_2(struct __sk_buff *ctx)
> > >  	return 0;
> > >  }
> > >  
> > > +SEC("?tc")
> > > +__success
> > 
> > Could you please extend this test to verify generated x86 assembly
> > code? (see __arch_x86_64 and __jited macro usage in verifier_tailcall_jit.c).
> 
> I’ll try to extend it, depending on the specific x86 implementation.
> 
> > Also, is it necessary to extend this test to actually verify returned
> > value?
> 
> Not necessary — let’s just return 0 here.

I mean a bit more broadly, make the bpf program run in an interrupt
and outside of the interrupt context and check the return value.
If it is a small wrapper around existing kernel function probably not
worth it, but you are adding custom logic with inlining.

Basically same thing Alexei asked in the sibling thread.