[PATCH bpf-next 2/3] selftests/bpf: Add stacktrace_ips test for tracepoint

[Andrii Nakryiko <andrii@kernel.org>]

Add a tp subtest that checks the stack captured by bpf_get_stack()
from a tracepoint program, recorded only for the test's own process.
Depending on static calls and inlining, the stack may or may not have
__traceiter_bpf_testmod_test_read in front of bpf_testmod_test_read,
so accept both. Also check that the entry after it differs: kernels
without commit 6d08340d1e35 ("Revert "perf/x86: Always store regs->ip
in perf_callchain_kernel()"") report the tracepoint's caller twice.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 .../selftests/bpf/prog_tests/stacktrace_ips.c | 54 +++++++++++++++++++
 .../selftests/bpf/progs/stacktrace_ips.c      | 13 +++++
 2 files changed, 67 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/stacktrace_ips.c b/tools/testing/selftests/bpf/prog_tests/stacktrace_ips.c
index da42b00e3d1f..a03d4c10c469 100644
--- a/tools/testing/selftests/bpf/prog_tests/stacktrace_ips.c
+++ b/tools/testing/selftests/bpf/prog_tests/stacktrace_ips.c
@@ -137,6 +137,58 @@ static void test_stacktrace_ips_raw_tp(void)
 	stacktrace_ips__destroy(skel);
 }
 
+static void test_stacktrace_ips_tp(void)
+{
+	__u64 traceiter_addr, read_addr, *ips;
+	struct stacktrace_ips *skel;
+	struct ksyms *ksyms = NULL;
+	struct ksym *ksym;
+	int i;
+
+	skel = stacktrace_ips__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "stacktrace_ips__open_and_load"))
+		return;
+
+	if (!skel->kconfig->CONFIG_UNWINDER_ORC) {
+		test__skip();
+		goto cleanup;
+	}
+
+	skel->bss->my_pid = getpid();
+
+	skel->links.tp_test = bpf_program__attach(skel->progs.tp_test);
+	if (!ASSERT_OK_PTR(skel->links.tp_test, "bpf_program__attach"))
+		goto cleanup;
+
+	trigger_module_test_read(1);
+
+	ksyms = load_kallsyms_local();
+	if (!ASSERT_OK_PTR(ksyms, "load_kallsyms_local"))
+		goto cleanup;
+	traceiter_addr = ksym_get_addr_local(ksyms, "__traceiter_bpf_testmod_test_read");
+	read_addr = ksym_get_addr_local(ksyms, "bpf_testmod_test_read");
+
+	/*
+	 * Depending on static calls and inlining, __traceiter_bpf_testmod_test_read
+	 * may or may not be in front of bpf_testmod_test_read.
+	 */
+	ips = skel->bss->tp_ips;
+	ksym = ksym_search_local(ksyms, ips[0]);
+	if (!ASSERT_OK_PTR(ksym, "ksym_search_local"))
+		goto cleanup;
+	i = ksym->addr == traceiter_addr ? 1 : 0;
+
+	ksym = ksym_search_local(ksyms, ips[i]);
+	if (!ASSERT_OK_PTR(ksym, "ksym_search_local"))
+		goto cleanup;
+	ASSERT_EQ(ksym->addr, read_addr, "stack_cmp");
+	ASSERT_NEQ(ips[i], ips[i + 1], "stack_dup");
+
+cleanup:
+	free_kallsyms_local(ksyms);
+	stacktrace_ips__destroy(skel);
+}
+
 static void test_stacktrace_ips_kprobe(bool retprobe)
 {
 	LIBBPF_OPTS(bpf_kprobe_opts, opts,
@@ -238,6 +290,8 @@ static void __test_stacktrace_ips(void)
 		test_stacktrace_ips_kprobe_multi(true);
 	if (test__start_subtest("raw_tp"))
 		test_stacktrace_ips_raw_tp();
+	if (test__start_subtest("tp"))
+		test_stacktrace_ips_tp();
 	if (test__start_subtest("kprobe"))
 		test_stacktrace_ips_kprobe(false);
 	if (test__start_subtest("kretprobe"))
diff --git a/tools/testing/selftests/bpf/progs/stacktrace_ips.c b/tools/testing/selftests/bpf/progs/stacktrace_ips.c
index 6830f2978613..df10ef3cb14d 100644
--- a/tools/testing/selftests/bpf/progs/stacktrace_ips.c
+++ b/tools/testing/selftests/bpf/progs/stacktrace_ips.c
@@ -53,6 +53,19 @@ int rawtp_test(void *ctx)
 	return 0;
 }
 
+__u64 tp_ips[128];
+int my_pid;
+
+SEC("tp/bpf_testmod/bpf_testmod_test_read")
+int tp_test(void *ctx)
+{
+	if (bpf_get_current_pid_tgid() >> 32 != my_pid)
+		return 0;
+
+	bpf_get_stack(ctx, tp_ips, sizeof(tp_ips), 0);
+	return 0;
+}
+
 SEC("fentry/bpf_testmod_stacktrace_test")
 int fentry_test(struct pt_regs *ctx)
 {
-- 
2.53.1-Meta