selftests/bpf: Add kprobe_multi attach test

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>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-11-jolsa@kernel.org

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 (file)
index 0000000..ded6b8c
--- /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 (file)
index 0000000..6616c08
--- /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 ca6abae..3d6217e 100644 (file)
--- 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;