Re: [PATCH bpf-next 4/4] selftests/bpf: validate jit behaviour for tail calls

Eduard Zingerman
2024-08-15T22:11:03Z

On Thu, 2024-08-15 at 15:07 -0700, Andrii Nakryiko wrote:

[...]

> > > Isn't that a bit counter-intuitive and potentially dangerous behavior
> > > for checking disassembly? If my assumption is correct, maybe we should
> > > add some sort of `__jit_x86("...")` placeholder to explicitly mark
> > > that we allow some amount of lines to be skipped, but otherwise be
> > > strict and require matching line-by-line?
> >
> > This is a valid concern.
> > What you suggest with "..." looks good.
>
> I'd add just that for now. _not and _next might be useful in the
> future, but meh.

If we commit to "..." now and decide to add _not and _next in the
future this would make __jit macro special. Which is not ideal, imo.
(on the other hand, tests can always be adjusted). …