Re: [PATCH bpf 3/3] selftests/bpf: Test gotol with large offsets

[Yonghong Song <yonghong.song@linux.dev>]

On 1/2/24 11:30 AM, Ilya Leoshkevich wrote:
> Test gotol with offsets that don't fit into a short (i.e., larger than
> 32k or smaller than -32k).
>
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>

It might be useful to explain why the test will fail
with unpriv mode (4K insn limit) just in case that
people are not aware of the reason.

Acked-by: Yonghong Song <yonghong.song@linux.dev>

> ---
>   .../selftests/bpf/progs/verifier_gotol.c      | 19 +++++++++++++++++++
>   1 file changed, 19 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/progs/verifier_gotol.c b/tools/testing/selftests/bpf/progs/verifier_gotol.c
> index d1edbcff9a18..05a329ee45ee 100644
> --- a/tools/testing/selftests/bpf/progs/verifier_gotol.c
> +++ b/tools/testing/selftests/bpf/progs/verifier_gotol.c
> @@ -33,6 +33,25 @@ l3_%=:							\
>   	: __clobber_all);
>   }
>   
> +SEC("socket")
> +__description("gotol, large_imm")
> +__success __failure_unpriv __retval(40000)
> +__naked void gotol_large_imm(void)
> +{
> +	asm volatile ("					\
> +	gotol 1f;					\
> +0:							\
> +	r0 = 0;						\
> +	.rept 40000;					\
> +	r0 += 1;					\
> +	.endr;						\
> +	exit;						\
> +1:	gotol 0b;					\
> +"	:
> +	:
> +	: __clobber_all);
> +}
> +
>   #else
>   
>   SEC("socket")