selftests/bpf: Use bpf_link__destroy in fill_link_info tests

The fill_link_info test keeps skeleton open and just creates
various links. We are wrongly calling bpf_link__detach after
each test to close them, we need to call bpf_link__destroy.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/bpf/20231125193130.834322-5-jolsa@kernel.org

tools/testing/selftests/bpf/prog_tests/fill_link_info.c

@@ -140,14 +140,14 @@ static void test_kprobe_fill_link_info(struct test_fill_link_info *skel,
 		.retprobe = type == BPF_PERF_EVENT_KRETPROBE,
 	);
 	ssize_t entry_offset = 0;
+	struct bpf_link *link;
 	int link_fd, err;
 
-	skel->links.kprobe_run = bpf_program__attach_kprobe_opts(skel->progs.kprobe_run,
-								 KPROBE_FUNC, &opts);
-	if (!ASSERT_OK_PTR(skel->links.kprobe_run, "attach_kprobe"))
+	link = bpf_program__attach_kprobe_opts(skel->progs.kprobe_run, KPROBE_FUNC, &opts);
+	if (!ASSERT_OK_PTR(link, "attach_kprobe"))
 		return;
 
-	link_fd = bpf_link__fd(skel->links.kprobe_run);
+	link_fd = bpf_link__fd(link);
 	if (!invalid) {
 		/* See also arch_adjust_kprobe_addr(). */
 		if (skel->kconfig->CONFIG_X86_KERNEL_IBT)
@@ -157,39 +157,41 @@ static void test_kprobe_fill_link_info(struct test_fill_link_info *skel,
 	} else {
 		kprobe_fill_invalid_user_buffer(link_fd);
 	}
-	bpf_link__detach(skel->links.kprobe_run);
+	bpf_link__destroy(link);
 }
 
 static void test_tp_fill_link_info(struct test_fill_link_info *skel)
 {
+	struct bpf_link *link;
 	int link_fd, err;
 
-	skel->links.tp_run = bpf_program__attach_tracepoint(skel->progs.tp_run, TP_CAT, TP_NAME);
-	if (!ASSERT_OK_PTR(skel->links.tp_run, "attach_tp"))
+	link = bpf_program__attach_tracepoint(skel->progs.tp_run, TP_CAT, TP_NAME);
+	if (!ASSERT_OK_PTR(link, "attach_tp"))
 		return;
 
-	link_fd = bpf_link__fd(skel->links.tp_run);
+	link_fd = bpf_link__fd(link);
 	err = verify_perf_link_info(link_fd, BPF_PERF_EVENT_TRACEPOINT, 0, 0, 0);
 	ASSERT_OK(err, "verify_perf_link_info");
-	bpf_link__detach(skel->links.tp_run);
+	bpf_link__destroy(link);
 }
 
 static void test_uprobe_fill_link_info(struct test_fill_link_info *skel,
 				       enum bpf_perf_event_type type)
 {
+	struct bpf_link *link;
 	int link_fd, err;
 
-	skel->links.uprobe_run = bpf_program__attach_uprobe(skel->progs.uprobe_run,
-							    type == BPF_PERF_EVENT_URETPROBE,
-							    0, /* self pid */
-							    UPROBE_FILE, uprobe_offset);
-	if (!ASSERT_OK_PTR(skel->links.uprobe_run, "attach_uprobe"))
+	link = bpf_program__attach_uprobe(skel->progs.uprobe_run,
+					  type == BPF_PERF_EVENT_URETPROBE,
+					  0, /* self pid */
+					  UPROBE_FILE, uprobe_offset);
+	if (!ASSERT_OK_PTR(link, "attach_uprobe"))
 		return;
 
-	link_fd = bpf_link__fd(skel->links.uprobe_run);
+	link_fd = bpf_link__fd(link);
 	err = verify_perf_link_info(link_fd, type, 0, uprobe_offset, 0);
 	ASSERT_OK(err, "verify_perf_link_info");
-	bpf_link__detach(skel->links.uprobe_run);
+	bpf_link__destroy(link);
 }
 
 static int verify_kmulti_link_info(int fd, bool retprobe)
@@ -278,24 +280,24 @@ static void test_kprobe_multi_fill_link_info(struct test_fill_link_info *skel,
 					     bool retprobe, bool invalid)
 {
 	LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);
+	struct bpf_link *link;
 	int link_fd, err;
 
 	opts.syms = kmulti_syms;
 	opts.cnt = KMULTI_CNT;
 	opts.retprobe = retprobe;
-	skel->links.kmulti_run = bpf_program__attach_kprobe_multi_opts(skel->progs.kmulti_run,
-								       NULL, &opts);
-	if (!ASSERT_OK_PTR(skel->links.kmulti_run, "attach_kprobe_multi"))
+	link = bpf_program__attach_kprobe_multi_opts(skel->progs.kmulti_run, NULL, &opts);
+	if (!ASSERT_OK_PTR(link, "attach_kprobe_multi"))
 		return;
 
-	link_fd = bpf_link__fd(skel->links.kmulti_run);
+	link_fd = bpf_link__fd(link);
 	if (!invalid) {
 		err = verify_kmulti_link_info(link_fd, retprobe);
 		ASSERT_OK(err, "verify_kmulti_link_info");
 	} else {
 		verify_kmulti_invalid_user_buffer(link_fd);
 	}
-	bpf_link__detach(skel->links.kmulti_run);
+	bpf_link__destroy(link);
 }
 
 void test_fill_link_info(void)