[PATCH 8/8] selftest/bpf: Add fprobe test for bpf_cookie values

Jiri Olsa
2022-02-02T13:54:42Z

Adding bpf_cookie test for kprobe attached by fprobe link.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
.../selftests/bpf/prog_tests/bpf_cookie.c | 73 +++++++++++++++++++
.../selftests/bpf/progs/fprobe_bpf_cookie.c | 62 ++++++++++++++++
2 files changed, 135 insertions(+)
create mode 100644 tools/testing/selftests/bpf/progs/fprobe_bpf_cookie.c

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
index cd10df6cd0fc..bf70d859c598 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
@@ -7,6 +7,7 @@
#include <unistd.h>
#include <test_progs.h>
#include "test_bpf_cookie.skel.h"
+#include "fprobe_bpf_cookie.skel.h"

/* uprobe attach point */
static void trigger_func(void)
@@ -63,6 +64,76 @@ static void kprobe_subtest(struct test_bpf_cookie *skel)
bpf_link__destroy(retlink2);
}

+static void fprobe_subtest(void)
+{
+ DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts);
+ int err, prog_fd, link1_fd = -1, link2_fd = -1;
+ struct fprobe_bpf_cookie *skel = NULL;
+ __u32 duration = 0, retval;
+ __u64 addrs[8], cookies[8];
+
+ skel = fprobe_bpf_cookie__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "fentry_raw_skel_load"))
+ goto cleanup;
+
+ 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]);
+
+ cookies[0] = 1;
+ cookies[1] = 2;
+ cookies[2] = 3;
+ cookies[3] = 4;
+ cookies[4] = 5;
+ cookies[5] = 6;
+ cookies[6] = 7;
+ cookies[7] = 8;
+
+ opts.fprobe.addrs = (__u64) &addrs;
+ opts.fprobe.cnt = 8;
+ opts.fprobe.bpf_cookies = (__u64) &cookies;
+ prog_fd = bpf_program__fd(skel->progs.test2);
+
+ link1_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_FPROBE, &opts);
+ if (!ASSERT_GE(link1_fd, 0, "link1_fd"))
+ return;
+
+ cookies[0] = 8;
+ cookies[1] = 7;
+ cookies[2] = 6;
+ cookies[3] = 5;
+ cookies[4] = 4;
+ cookies[5] = 3;
+ cookies[6] = 2;
+ cookies[7] = 1;
+
+ opts.flags = BPF_F_FPROBE_RETURN;
+ prog_fd = bpf_program__fd(skel->progs.test3);
+
+ link2_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_FPROBE, &opts);
+ if (!ASSERT_GE(link2_fd, 0, "link2_fd"))
+ goto cleanup;
+
+ prog_fd = bpf_program__fd(skel->progs.test1);
+ err = bpf_prog_test_run(prog_fd, 1, NULL, 0,
+ NULL, NULL, &retval, &duration);
+ ASSERT_OK(err, "test_run");
+ ASSERT_EQ(retval, 0, "test_run");
+
+ ASSERT_EQ(skel->bss->test2_result, 8, "test2_result");
+ ASSERT_EQ(skel->bss->test3_result, 8, "test3_result");
+
+cleanup:
+ close(link1_fd);
+ close(link2_fd);
+ fprobe_bpf_cookie__destroy(skel);
+}
+
static void uprobe_subtest(struct test_bpf_cookie *skel)
{
DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, opts);
@@ -249,6 +320,8 @@ void test_bpf_cookie(void)

if (test__start_subtest("kprobe"))
kprobe_subtest(skel);
+ if (test__start_subtest("rawkprobe"))
+ fprobe_subtest();
if (test__start_subtest("uprobe"))
uprobe_subtest(skel);
if (test__start_subtest("tracepoint"))
diff --git a/tools/testing/selftests/bpf/progs/fprobe_bpf_cookie.c b/tools/testing/selftests/bpf/progs/fprobe_bpf_cookie.c
new file mode 100644
index 000000000000..42cb109e5a30
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/fprobe_bpf_cookie.c
@@ -0,0 +1,62 @@
+// 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/bpf_fentry_test*")
+int test2(struct pt_regs *ctx)
+{
+ __u64 cookie = bpf_get_attach_cookie(ctx);
+ __u64 addr = bpf_get_func_ip(ctx);
+
+ test2_result += (const void *) addr == &bpf_fentry_test1 && cookie == 1;
+ test2_result += (const void *) addr == &bpf_fentry_test2 && cookie == 2;
+ test2_result += (const void *) addr == &bpf_fentry_test3 && cookie == 3;
+ test2_result += (const void *) addr == &bpf_fentry_test4 && cookie == 4;
+ test2_result += (const void *) addr == &bpf_fentry_test5 && cookie == 5;
+ test2_result += (const void *) addr == &bpf_fentry_test6 && cookie == 6;
+ test2_result += (const void *) addr == &bpf_fentry_test7 && cookie == 7;
+ test2_result += (const void *) addr == &bpf_fentry_test8 && cookie == 8;
+
+ return 0;
+}
+
+__u64 test3_result = 0;
+
+SEC("kretprobe/bpf_fentry_test*")
+int test3(struct pt_regs *ctx)
+{
+ __u64 cookie = bpf_get_attach_cookie(ctx);
+ __u64 addr = bpf_get_func_ip(ctx);
+
+ test3_result += (const void *) addr == &bpf_fentry_test1 && cookie == 8;
+ test3_result += (const void *) addr == &bpf_fentry_test2 && cookie == 7;
+ test3_result += (const void *) addr == &bpf_fentry_test3 && cookie == 6;
+ test3_result += (const void *) addr == &bpf_fentry_test4 && cookie == 5;
+ test3_result += (const void *) addr == &bpf_fentry_test5 && cookie == 4;
+ test3_result += (const void *) addr == &bpf_fentry_test6 && cookie == 3;
+ test3_result += (const void *) addr == &bpf_fentry_test7 && cookie == 2;
+ test3_result += (const void *) addr == &bpf_fentry_test8 && cookie == 1;
+
+ return 0;
+}
--
2.34.1