On Fri, 2023-11-17 at 11:47 -0500, Andrii Nakryiko wrote:
> On Wed, Nov 15, 2023 at 9:18 PM Eduard Zingerman <eddyz87@xxxxxxxxx> wrote:
> >
> > A test case to verify that imprecise scalars widening is applied to
> > callback bodies on repetative iteration.
>
> typo: repetitive? repeating? successive? subsequent?
I'll configure spell-checking, I promise.
[...]
> > +static int widening_cb(__u32 idx, struct num_context *ctx)
> > +{
> > + ++ctx->i;
> > + return 0;
> > +}
> > +
> > +SEC("?raw_tp")
> > +__success
> > +int widening(void *unused)
> > +{
> > + struct num_context loop_ctx = { .i = 0, .j = 1 };
> > +
> > + bpf_loop(100, widening_cb, &loop_ctx, 0);
> > + /* loop_ctx.j is not changed during callback iteration,
> > + * verifier should not apply widening to it.
> > + */
> > + return choice_arr[loop_ctx.j];
>
> would the test be a bit more interesting if you use loop_ctx.i here?
> `return choice_arr[loop_ctx.i & 1];` ?
It would force precision for 'loop_ctx.i', precise values are not widened.
>
> > +}
> > +
