Re: [PATCHv3 bpf-next 24/24] selftests/bpf: Add tracing multi attach rollback tests

[Jiri Olsa <olsajiri@gmail.com>]

On Tue, Mar 17, 2026 at 11:20:59AM +0800, Leon Hwang wrote:

SNIP

> > +static void test_rollback_unlink(void)
> > +{
> > +	LIBBPF_OPTS(bpf_tracing_multi_opts, opts);
> > +	struct tracing_multi_rollback **fillers;
> > +	struct tracing_multi_rollback *skel;
> > +	size_t cnt = FUNCS_CNT;
> > +	__u32 *ids = NULL;
> > +	int err, max;
> > +
> > +	max = get_bpf_max_tramp_links();
> > +	if (!ASSERT_GE(max, 1, "bpf_max_tramp_links"))
> > +		return;
> > +
> > +	/* Attach maximum allowed programs to bpf_fentry_test10 */
> > +	fillers = fillers_load_and_link(max);
> > +	if (!ASSERT_OK_PTR(fillers, "fillers_load_and_link"))
> > +		return;
> > +
> > +	skel = tracing_multi_rollback__open();
> > +	if (!ASSERT_OK_PTR(skel, "tracing_multi_rollback__open"))
> > +		goto cleanup;
> > +
> > +	bpf_program__set_autoload(skel->progs.test_fentry, true);
> > +	bpf_program__set_autoload(skel->progs.test_fexit, true);
> > +
> > +	/*
> > +	 * Attach tracing_multi link on bpf_fentry_test1-10, which will
> > +	 * fail on bpf_fentry_test10 function, because it already has
> > +	 * maximum allowed programs attached.
> > +	 *
> > +	 * The rollback needs to unlink already link-ed trampolines and
> > +	 * put all of them.
> > +	 */
> > +	err = tracing_multi_rollback__load(skel);
> > +	if (!ASSERT_OK(err, "tracing_multi_rollback__load"))
> > +		goto cleanup;
> > +
> > +	ids = get_ids(bpf_fentry_test, cnt, NULL);
> > +	if (!ASSERT_OK_PTR(ids, "get_ids"))
> > +		goto cleanup;
> > +
> > +	opts.ids = ids;
> > +	opts.cnt = cnt;
> > +
> > +	skel->bss->pid = getpid();
> > +
> > +	skel->links.test_fentry = bpf_program__attach_tracing_multi(skel->progs.test_fentry,
> > +						NULL, &opts);
> > +	if (!ASSERT_ERR_PTR(skel->links.test_fentry, "bpf_program__attach_tracing_multi"))
> > +		goto cleanup;
> > +
> > +	skel->links.test_fexit = bpf_program__attach_tracing_multi(skel->progs.test_fexit,
> > +						NULL, &opts);
> > +	if (!ASSERT_ERR_PTR(skel->links.test_fexit, "bpf_program__attach_tracing_multi"))
> > +		goto cleanup;
> > +
> > +	tracing_multi_rollback_run(skel);
> > +
> > +cleanup:
> 	tracing_multi_rollback__destroy(skel); is missed to destroy skel?

it is, will add, thanks

jirka