From: Jiri Olsa <jolsa@kernel.org>
Date: Wed, 20 Sep 2023 21:31:45 +0000 (+0200)
Subject: selftests/bpf: Add test for recursion counts of perf event link tracepoint
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=85981e0f9e9fc882578f0ad7488d6c59193dd187;p=linux.git

selftests/bpf: Add test for recursion counts of perf event link tracepoint

Adding selftest that puts kprobe on bpf_fentry_test1 that calls bpf_printk
and invokes bpf_trace_printk tracepoint. The bpf_trace_printk tracepoint
has test[234] programs attached to it.

Because kprobe execution goes through bpf_prog_active check, programs
attached to the tracepoint will fail the recursion check and increment the
recursion_misses stats.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Song Liu <song@kernel.org>
Reviewed-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/bpf/20230920213145.1941596-10-jolsa@kernel.org
---

diff --git a/tools/testing/selftests/bpf/prog_tests/missed.c b/tools/testing/selftests/bpf/prog_tests/missed.c
index 54aaf2f8ad8c3..24ade11f5c05f 100644
--- a/tools/testing/selftests/bpf/prog_tests/missed.c
+++ b/tools/testing/selftests/bpf/prog_tests/missed.c
@@ -2,6 +2,7 @@
 #include <test_progs.h>
 #include "missed_kprobe.skel.h"
 #include "missed_kprobe_recursion.skel.h"
+#include "missed_tp_recursion.skel.h"
 
 /*
  * Putting kprobe on bpf_fentry_test1 that calls bpf_kfunc_common_test
@@ -89,10 +90,49 @@ cleanup:
 	missed_kprobe_recursion__destroy(skel);
 }
 
+/*
+ * Putting kprobe on bpf_fentry_test1 that calls bpf_printk and invokes
+ * bpf_trace_printk tracepoint. The bpf_trace_printk tracepoint has test[234]
+ * programs attached to it.
+ *
+ * Because kprobe execution goes through bpf_prog_active check, programs
+ * attached to the tracepoint will fail the recursion check and increment
+ * the recursion_misses stats.
+ */
+static void test_missed_tp_recursion(void)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+	struct missed_tp_recursion *skel;
+	int err, prog_fd;
+
+	skel = missed_tp_recursion__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "missed_tp_recursion__open_and_load"))
+		goto cleanup;
+
+	err = missed_tp_recursion__attach(skel);
+	if (!ASSERT_OK(err, "missed_tp_recursion__attach"))
+		goto cleanup;
+
+	prog_fd = bpf_program__fd(skel->progs.trigger);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	ASSERT_OK(err, "test_run");
+	ASSERT_EQ(topts.retval, 0, "test_run");
+
+	ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test1)), 0, "test1_recursion_misses");
+	ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test2)), 1, "test2_recursion_misses");
+	ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test3)), 1, "test3_recursion_misses");
+	ASSERT_EQ(get_missed_count(bpf_program__fd(skel->progs.test4)), 1, "test4_recursion_misses");
+
+cleanup:
+	missed_tp_recursion__destroy(skel);
+}
+
 void test_missed(void)
 {
 	if (test__start_subtest("perf_kprobe"))
 		test_missed_perf_kprobe();
 	if (test__start_subtest("kprobe_recursion"))
 		test_missed_kprobe_recursion();
+	if (test__start_subtest("tp_recursion"))
+		test_missed_tp_recursion();
 }
diff --git a/tools/testing/selftests/bpf/progs/missed_tp_recursion.c b/tools/testing/selftests/bpf/progs/missed_tp_recursion.c
new file mode 100644
index 0000000000000..762385f827c50
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/missed_tp_recursion.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+/*
+ * No tests in here, just to trigger 'bpf_fentry_test*'
+ * through tracing test_run
+ */
+SEC("fentry/bpf_modify_return_test")
+int BPF_PROG(trigger)
+{
+	return 0;
+}
+
+SEC("kprobe/bpf_fentry_test1")
+int test1(struct pt_regs *ctx)
+{
+	bpf_printk("test");
+	return 0;
+}
+
+SEC("tp/bpf_trace/bpf_trace_printk")
+int test2(struct pt_regs *ctx)
+{
+	return 0;
+}
+
+SEC("tp/bpf_trace/bpf_trace_printk")
+int test3(struct pt_regs *ctx)
+{
+	return 0;
+}
+
+SEC("tp/bpf_trace/bpf_trace_printk")
+int test4(struct pt_regs *ctx)
+{
+	return 0;
+}