selftests/bpf: Fix attach_probe in parallel mode

This patch makes attach_probe uses its own method as attach point,
avoiding conflict with other tests like bpf_cookie.
Signed-off-by: Yucong Sun <sunyucong@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211025223345.2136168-4-fallentree@fb.com

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

@@ -5,6 +5,11 @@
 /* this is how USDT semaphore is actually defined, except volatile modifier */
 volatile unsigned short uprobe_ref_ctr __attribute__((unused)) __attribute((section(".probes")));
 
+/* attach point */
+static void method(void) {
+	return ;
+}
+
 void test_attach_probe(void)
 {
 	DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts);
@@ -33,7 +38,7 @@ void test_attach_probe(void)
 	if (CHECK(base_addr < 0, "get_base_addr",
 		  "failed to find base addr: %zd", base_addr))
 		return;
-	uprobe_offset = get_uprobe_offset(&get_base_addr, base_addr);
+	uprobe_offset = get_uprobe_offset(&method, base_addr);
 
 	ref_ctr_offset = get_rel_offset((uintptr_t)&uprobe_ref_ctr);
 	if (!ASSERT_GE(ref_ctr_offset, 0, "ref_ctr_offset"))
@@ -98,7 +103,7 @@ void test_attach_probe(void)
 		goto cleanup;
 
 	/* trigger & validate uprobe & uretprobe */
-	get_base_addr();
+	method();
 
 	if (CHECK(skel->bss->uprobe_res != 3, "check_uprobe_res",
 		  "wrong uprobe res: %d\n", skel->bss->uprobe_res))