selftests/bpf: Add kprobe_multi kmod attach api tests

Adding kprobe_multi kmod attach api tests that attach bpf_testmod
functions via bpf_program__attach_kprobe_multi_opts.

Running it as serial test, because we don't want other tests to
reload bpf_testmod while it's running.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20221025134148.3300700-9-jolsa@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

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

+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include "kprobe_multi.skel.h"
+#include "trace_helpers.h"
+#include "bpf/libbpf_internal.h"
+
+static void kprobe_multi_testmod_check(struct kprobe_multi *skel)
+{
+	ASSERT_EQ(skel->bss->kprobe_testmod_test1_result, 1, "kprobe_test1_result");
+	ASSERT_EQ(skel->bss->kprobe_testmod_test2_result, 1, "kprobe_test2_result");
+	ASSERT_EQ(skel->bss->kprobe_testmod_test3_result, 1, "kprobe_test3_result");
+
+	ASSERT_EQ(skel->bss->kretprobe_testmod_test1_result, 1, "kretprobe_test1_result");
+	ASSERT_EQ(skel->bss->kretprobe_testmod_test2_result, 1, "kretprobe_test2_result");
+	ASSERT_EQ(skel->bss->kretprobe_testmod_test3_result, 1, "kretprobe_test3_result");
+}
+
+static void test_testmod_attach_api(struct bpf_kprobe_multi_opts *opts)
+{
+	struct kprobe_multi *skel = NULL;
+
+	skel = kprobe_multi__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "fentry_raw_skel_load"))
+		return;
+
+	skel->bss->pid = getpid();
+
+	skel->links.test_kprobe_testmod = bpf_program__attach_kprobe_multi_opts(
+						skel->progs.test_kprobe_testmod,
+						NULL, opts);
+	if (!skel->links.test_kprobe_testmod)
+		goto cleanup;
+
+	opts->retprobe = true;
+	skel->links.test_kretprobe_testmod = bpf_program__attach_kprobe_multi_opts(
+						skel->progs.test_kretprobe_testmod,
+						NULL, opts);
+	if (!skel->links.test_kretprobe_testmod)
+		goto cleanup;
+
+	ASSERT_OK(trigger_module_test_read(1), "trigger_read");
+	kprobe_multi_testmod_check(skel);
+
+cleanup:
+	kprobe_multi__destroy(skel);
+}
+
+static void test_testmod_attach_api_addrs(void)
+{
+	LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);
+	unsigned long long addrs[3];
+
+	addrs[0] = ksym_get_addr("bpf_testmod_fentry_test1");
+	ASSERT_NEQ(addrs[0], 0, "ksym_get_addr");
+	addrs[1] = ksym_get_addr("bpf_testmod_fentry_test2");
+	ASSERT_NEQ(addrs[1], 0, "ksym_get_addr");
+	addrs[2] = ksym_get_addr("bpf_testmod_fentry_test3");
+	ASSERT_NEQ(addrs[2], 0, "ksym_get_addr");
+
+	opts.addrs = (const unsigned long *) addrs;
+	opts.cnt = ARRAY_SIZE(addrs);
+
+	test_testmod_attach_api(&opts);
+}
+
+static void test_testmod_attach_api_syms(void)
+{
+	LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);
+	const char *syms[3] = {
+		"bpf_testmod_fentry_test1",
+		"bpf_testmod_fentry_test2",
+		"bpf_testmod_fentry_test3",
+	};
+
+	opts.syms = syms;
+	opts.cnt = ARRAY_SIZE(syms);
+	test_testmod_attach_api(&opts);
+}
+
+void serial_test_kprobe_multi_testmod_test(void)
+{
+	if (!ASSERT_OK(load_kallsyms_refresh(), "load_kallsyms_refresh"))
+		return;
+
+	if (test__start_subtest("testmod_attach_api_syms"))
+		test_testmod_attach_api_syms();
+	if (test__start_subtest("testmod_attach_api_addrs"))
+		test_testmod_attach_api_addrs();
+}

tools/testing/selftests/bpf/progs/kprobe_multi.c

@@ -110,3 +110,53 @@ int test_kretprobe_manual(struct pt_regs *ctx)
 	kprobe_multi_check(ctx, true);
 	return 0;
 }
+
+extern const void bpf_testmod_fentry_test1 __ksym;
+extern const void bpf_testmod_fentry_test2 __ksym;
+extern const void bpf_testmod_fentry_test3 __ksym;
+
+__u64 kprobe_testmod_test1_result = 0;
+__u64 kprobe_testmod_test2_result = 0;
+__u64 kprobe_testmod_test3_result = 0;
+
+__u64 kretprobe_testmod_test1_result = 0;
+__u64 kretprobe_testmod_test2_result = 0;
+__u64 kretprobe_testmod_test3_result = 0;
+
+static void kprobe_multi_testmod_check(void *ctx, bool is_return)
+{
+	if (bpf_get_current_pid_tgid() >> 32 != pid)
+		return;
+
+	__u64 addr = bpf_get_func_ip(ctx);
+
+	if (is_return) {
+		if ((const void *) addr == &bpf_testmod_fentry_test1)
+			kretprobe_testmod_test1_result = 1;
+		if ((const void *) addr == &bpf_testmod_fentry_test2)
+			kretprobe_testmod_test2_result = 1;
+		if ((const void *) addr == &bpf_testmod_fentry_test3)
+			kretprobe_testmod_test3_result = 1;
+	} else {
+		if ((const void *) addr == &bpf_testmod_fentry_test1)
+			kprobe_testmod_test1_result = 1;
+		if ((const void *) addr == &bpf_testmod_fentry_test2)
+			kprobe_testmod_test2_result = 1;
+		if ((const void *) addr == &bpf_testmod_fentry_test3)
+			kprobe_testmod_test3_result = 1;
+	}
+}
+
+SEC("kprobe.multi")
+int test_kprobe_testmod(struct pt_regs *ctx)
+{
+	kprobe_multi_testmod_check(ctx, false);
+	return 0;
+}
+
+SEC("kretprobe.multi")
+int test_kretprobe_testmod(struct pt_regs *ctx)
+{
+	kprobe_multi_testmod_check(ctx, true);
+	return 0;
+}