[PATCHv3 bpf-next 10/13] selftests/bpf: Add kprobe_multi attach test

Jiri Olsa
2022-03-16T12:26:47Z

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 | 141 ++++++++++++++++++
.../selftests/bpf/progs/kprobe_multi.c | 95 ++++++++++++
tools/testing/selftests/bpf/trace_helpers.c | 7 +
3 files changed, 243 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..ded6b8c8ec05
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
@@ -0,0 +1,141 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include "kprobe_multi.skel.h"
+#include "trace_helpers.h"
+
+static void kprobe_multi_test_run(struct kprobe_multi *skel)
+{
+ LIBBPF_OPTS(bpf_test_run_opts, topts);
+ int err, prog_fd;
+
+ 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(skel->bss->kprobe_test1_result, 1, "kprobe_test1_result");
+ ASSERT_EQ(skel->bss->kprobe_test2_result, 1, "kprobe_test2_result");
+ ASSERT_EQ(skel->bss->kprobe_test3_result, 1, "kprobe_test3_result");
+ ASSERT_EQ(skel->bss->kprobe_test4_result, 1, "kprobe_test4_result");
+ ASSERT_EQ(skel->bss->kprobe_test5_result, 1, "kprobe_test5_result");
+ ASSERT_EQ(skel->bss->kprobe_test6_result, 1, "kprobe_test6_result");
+ ASSERT_EQ(skel->bss->kprobe_test7_result, 1, "kprobe_test7_result");
+ ASSERT_EQ(skel->bss->kprobe_test8_result, 1, "kprobe_test8_result");
+
+ ASSERT_EQ(skel->bss->kretprobe_test1_result, 1, "kretprobe_test1_result");
+ ASSERT_EQ(skel->bss->kretprobe_test2_result, 1, "kretprobe_test2_result");
+ ASSERT_EQ(skel->bss->kretprobe_test3_result, 1, "kretprobe_test3_result");
+ ASSERT_EQ(skel->bss->kretprobe_test4_result, 1, "kretprobe_test4_result");
+ ASSERT_EQ(skel->bss->kretprobe_test5_result, 1, "kretprobe_test5_result");
+ ASSERT_EQ(skel->bss->kretprobe_test6_result, 1, "kretprobe_test6_result");
+ ASSERT_EQ(skel->bss->kretprobe_test7_result, 1, "kretprobe_test7_result");
+ ASSERT_EQ(skel->bss->kretprobe_test8_result, 1, "kretprobe_test8_result");
+}
+
+static void test_skel_api(void)
+{
+ struct kprobe_multi *skel = NULL;
+ int err;
+
+ skel = kprobe_multi__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "kprobe_multi__open_and_load"))
+ goto cleanup;
+
+ skel->bss->pid = getpid();
+ err = kprobe_multi__attach(skel);
+ if (!ASSERT_OK(err, "kprobe_multi__attach"))
+ goto cleanup;
+
+ kprobe_multi_test_run(skel);
+
+cleanup:
+ kprobe_multi__destroy(skel);
+}
+
+static void test_link_api(struct bpf_link_create_opts *opts)
+{
+ int 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;
+
+ skel->bss->pid = getpid();
+ prog_fd = bpf_program__fd(skel->progs.test_kprobe);
+ 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.test_kretprobe);
+ link2_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_KPROBE_MULTI, opts);
+ if (!ASSERT_GE(link2_fd, 0, "link_fd"))
+ goto cleanup;
+
+ kprobe_multi_test_run(skel);
+
+cleanup:
+ if (link1_fd != -1)
+ close(link1_fd);
+ if (link2_fd != -1)
+ close(link2_fd);
+ kprobe_multi__destroy(skel);
+}
+
+#define GET_ADDR(__sym, __addr) ({ \
+ __addr = ksym_get_addr(__sym); \
+ if (!ASSERT_NEQ(__addr, 0, "kallsyms load failed for " #__sym)) \
+ return; \
+})
+
+static void test_link_api_addrs(void)
+{
+ LIBBPF_OPTS(bpf_link_create_opts, opts);
+ unsigned long long addrs[8];
+
+ GET_ADDR("bpf_fentry_test1", addrs[0]);
+ GET_ADDR("bpf_fentry_test2", addrs[1]);
+ GET_ADDR("bpf_fentry_test3", addrs[2]);
+ GET_ADDR("bpf_fentry_test4", addrs[3]);
+ GET_ADDR("bpf_fentry_test5", addrs[4]);
+ GET_ADDR("bpf_fentry_test6", addrs[5]);
+ GET_ADDR("bpf_fentry_test7", addrs[6]);
+ GET_ADDR("bpf_fentry_test8", addrs[7]);
+
+ opts.kprobe_multi.addrs = (const unsigned long*) addrs;
+ opts.kprobe_multi.cnt = ARRAY_SIZE(addrs);
+ test_link_api(&opts);
+}
+
+static void test_link_api_syms(void)
+{
+ 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 = syms;
+ opts.kprobe_multi.cnt = ARRAY_SIZE(syms);
+ test_link_api(&opts);
+}
+
+void test_kprobe_multi_test(void)
+{
+ if (!ASSERT_OK(load_kallsyms(), "load_kallsyms"))
+ return;
+
+ if (test__start_subtest("skel_api"))
+ test_skel_api();
+ if (test__start_subtest("link_api_addrs"))
+ test_link_api_syms();
+ if (test__start_subtest("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..6616c082c8c2
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kprobe_multi.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <stdbool.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;
+
+int pid = 0;
+
+__u64 kprobe_test1_result = 0;
+__u64 kprobe_test2_result = 0;
+__u64 kprobe_test3_result = 0;
+__u64 kprobe_test4_result = 0;
+__u64 kprobe_test5_result = 0;
+__u64 kprobe_test6_result = 0;
+__u64 kprobe_test7_result = 0;
+__u64 kprobe_test8_result = 0;
+
+__u64 kretprobe_test1_result = 0;
+__u64 kretprobe_test2_result = 0;
+__u64 kretprobe_test3_result = 0;
+__u64 kretprobe_test4_result = 0;
+__u64 kretprobe_test5_result = 0;
+__u64 kretprobe_test6_result = 0;
+__u64 kretprobe_test7_result = 0;
+__u64 kretprobe_test8_result = 0;
+
+static void kprobe_multi_check(void *ctx, bool is_return)
+{
+ if (bpf_get_current_pid_tgid() >> 32 != pid)
+ return;
+
+ __u64 addr = bpf_get_func_ip(ctx);
+
+#define SET(__var, __addr) ({ \
+ if ((const void *) addr == __addr) \
+ __var = 1; \
+})
+
+ if (is_return) {
+ SET(kretprobe_test1_result, &bpf_fentry_test1);
+ SET(kretprobe_test2_result, &bpf_fentry_test2);
+ SET(kretprobe_test3_result, &bpf_fentry_test3);
+ SET(kretprobe_test4_result, &bpf_fentry_test4);
+ SET(kretprobe_test5_result, &bpf_fentry_test5);
+ SET(kretprobe_test6_result, &bpf_fentry_test6);
+ SET(kretprobe_test7_result, &bpf_fentry_test7);
+ SET(kretprobe_test8_result, &bpf_fentry_test8);
+ } else {
+ SET(kprobe_test1_result, &bpf_fentry_test1);
+ SET(kprobe_test2_result, &bpf_fentry_test2);
+ SET(kprobe_test3_result, &bpf_fentry_test3);
+ SET(kprobe_test4_result, &bpf_fentry_test4);
+ SET(kprobe_test5_result, &bpf_fentry_test5);
+ SET(kprobe_test6_result, &bpf_fentry_test6);
+ SET(kprobe_test7_result, &bpf_fentry_test7);
+ SET(kprobe_test8_result, &bpf_fentry_test8);
+ }
+
+#undef SET
+}
+
+/*
+ * 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.multi/bpf_fentry_tes??")
+int test_kprobe(struct pt_regs *ctx)
+{
+ kprobe_multi_check(ctx, false);
+ return 0;
+}
+
+SEC("kretprobe.multi/bpf_fentry_test*")
+int test_kretprobe(struct pt_regs *ctx)
+{
+ kprobe_multi_check(ctx, true);
+ return 0;
+}
diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c
index ca6abae9b09c..3d6217e3aff7 100644
--- a/tools/testing/selftests/bpf/trace_helpers.c
+++ b/tools/testing/selftests/bpf/trace_helpers.c
@@ -34,6 +34,13 @@ int load_kallsyms(void)
if (!f)
return -ENOENT;

+ /*
+ * This is called/used from multiplace places,
+ * load symbols just once.
+ */
+ if (sym_cnt)
+ return 0;
+
while (fgets(buf, sizeof(buf), f)) {
if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3)
break;
--
2.35.1