[PATCH 09/10] selftest/bpf: Add kprobe_multi attach test

Jiri Olsa
2022-02-22T17:08:28Z

Adding kprobe_multi attach test that uses new fprobe interface to
attach kprobe program to multiple functions.

The test is attaching programs to bpf_fentry_test* functions and
uses single trampoline program bpf_prog_test_run to trigger
bpf_fentry_test* functions.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
.../bpf/prog_tests/kprobe_multi_test.c | 115 ++++++++++++++++++
.../selftests/bpf/progs/kprobe_multi.c | 58 +++++++++
2 files changed, 173 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
create mode 100644 tools/testing/selftests/bpf/progs/kprobe_multi.c

diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
new file mode 100644
index 000000000000..f5567c3865d4
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include "kprobe_multi.skel.h"
+#include "trace_helpers.h"
+
+static void test_skel_api(void)
+{
+ LIBBPF_OPTS(bpf_test_run_opts, topts);
+ struct kprobe_multi *skel = NULL;
+ int err, prog_fd;
+
+ skel = kprobe_multi__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "kprobe_multi__open_and_load"))
+ goto cleanup;
+
+ err = kprobe_multi__attach(skel);
+ if (!ASSERT_OK(err, "kprobe_multi__attach"))
+ goto cleanup;
+
+ prog_fd = bpf_program__fd(skel->progs.test1);
+ err = bpf_prog_test_run_opts(prog_fd, &topts);
+ ASSERT_OK(err, "test_run");
+ ASSERT_EQ(topts.retval, 0, "test_run");
+
+ ASSERT_EQ(skel->bss->test2_result, 8, "test2_result");
+ ASSERT_EQ(skel->bss->test3_result, 8, "test3_result");
+
+cleanup:
+ kprobe_multi__destroy(skel);
+}
+
+static void test_link_api(struct bpf_link_create_opts *opts)
+{
+ LIBBPF_OPTS(bpf_test_run_opts, topts);
+ int err, prog_fd, link1_fd = -1, link2_fd = -1;
+ struct kprobe_multi *skel = NULL;
+
+ skel = kprobe_multi__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "fentry_raw_skel_load"))
+ goto cleanup;
+
+ prog_fd = bpf_program__fd(skel->progs.test2);
+ link1_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_KPROBE_MULTI, opts);
+ if (!ASSERT_GE(link1_fd, 0, "link_fd"))
+ goto cleanup;
+
+ opts->kprobe_multi.flags = BPF_F_KPROBE_MULTI_RETURN;
+ prog_fd = bpf_program__fd(skel->progs.test3);
+ link2_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_KPROBE_MULTI, opts);
+ if (!ASSERT_GE(link2_fd, 0, "link_fd"))
+ goto cleanup;
+
+ skel->bss->test2_result = 0;
+ skel->bss->test3_result = 0;
+
+ prog_fd = bpf_program__fd(skel->progs.test1);
+ err = bpf_prog_test_run_opts(prog_fd, &topts);
+ ASSERT_OK(err, "test_run");
+ ASSERT_EQ(topts.retval, 0, "test_run");
+
+ ASSERT_EQ(skel->bss->test2_result, 8, "test2_result");
+ ASSERT_EQ(skel->bss->test3_result, 8, "test3_result");
+
+cleanup:
+ if (link1_fd != -1)
+ close(link1_fd);
+ if (link2_fd != -1)
+ close(link2_fd);
+ kprobe_multi__destroy(skel);
+}
+
+static void test_link_api_addrs(void)
+{
+ DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts);
+ __u64 addrs[8];
+
+ kallsyms_find("bpf_fentry_test1", &addrs[0]);
+ kallsyms_find("bpf_fentry_test2", &addrs[1]);
+ kallsyms_find("bpf_fentry_test3", &addrs[2]);
+ kallsyms_find("bpf_fentry_test4", &addrs[3]);
+ kallsyms_find("bpf_fentry_test5", &addrs[4]);
+ kallsyms_find("bpf_fentry_test6", &addrs[5]);
+ kallsyms_find("bpf_fentry_test7", &addrs[6]);
+ kallsyms_find("bpf_fentry_test8", &addrs[7]);
+
+ opts.kprobe_multi.addrs = (__u64) addrs;
+ opts.kprobe_multi.cnt = 8;
+ test_link_api(&opts);
+}
+
+static void test_link_api_syms(void)
+{
+ DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts);
+ const char *syms[8] = {
+ "bpf_fentry_test1",
+ "bpf_fentry_test2",
+ "bpf_fentry_test3",
+ "bpf_fentry_test4",
+ "bpf_fentry_test5",
+ "bpf_fentry_test6",
+ "bpf_fentry_test7",
+ "bpf_fentry_test8",
+ };
+
+ opts.kprobe_multi.syms = (__u64) syms;
+ opts.kprobe_multi.cnt = 8;
+ test_link_api(&opts);
+}
+
+void test_kprobe_multi_test(void)
+{
+ test_skel_api();
+ test_link_api_syms();
+ test_link_api_addrs();
+}
diff --git a/tools/testing/selftests/bpf/progs/kprobe_multi.c b/tools/testing/selftests/bpf/progs/kprobe_multi.c
new file mode 100644
index 000000000000..71318c65931c
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kprobe_multi.c
@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+extern const void bpf_fentry_test1 __ksym;
+extern const void bpf_fentry_test2 __ksym;
+extern const void bpf_fentry_test3 __ksym;
+extern const void bpf_fentry_test4 __ksym;
+extern const void bpf_fentry_test5 __ksym;
+extern const void bpf_fentry_test6 __ksym;
+extern const void bpf_fentry_test7 __ksym;
+extern const void bpf_fentry_test8 __ksym;
+
+/* No tests, just to trigger bpf_fentry_test* through tracing test_run */
+SEC("fentry/bpf_modify_return_test")
+int BPF_PROG(test1)
+{
+ return 0;
+}
+
+__u64 test2_result = 0;
+
+SEC("kprobe.multi/bpf_fentry_test?")
+int test2(struct pt_regs *ctx)
+{
+ __u64 addr = bpf_get_func_ip(ctx);
+
+ test2_result += (const void *) addr == &bpf_fentry_test1 ||
+ (const void *) addr == &bpf_fentry_test2 ||
+ (const void *) addr == &bpf_fentry_test3 ||
+ (const void *) addr == &bpf_fentry_test4 ||
+ (const void *) addr == &bpf_fentry_test5 ||
+ (const void *) addr == &bpf_fentry_test6 ||
+ (const void *) addr == &bpf_fentry_test7 ||
+ (const void *) addr == &bpf_fentry_test8;
+ return 0;
+}
+
+__u64 test3_result = 0;
+
+SEC("kretprobe.multi/bpf_fentry_test*")
+int test3(struct pt_regs *ctx)
+{
+ __u64 addr = bpf_get_func_ip(ctx);
+
+ test3_result += (const void *) addr == &bpf_fentry_test1 ||
+ (const void *) addr == &bpf_fentry_test2 ||
+ (const void *) addr == &bpf_fentry_test3 ||
+ (const void *) addr == &bpf_fentry_test4 ||
+ (const void *) addr == &bpf_fentry_test5 ||
+ (const void *) addr == &bpf_fentry_test6 ||
+ (const void *) addr == &bpf_fentry_test7 ||
+ (const void *) addr == &bpf_fentry_test8;
+ return 0;
+}
--
2.35.1