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

From: Jiri Olsa <[email-masked]>
Date: Wed, 2 Feb 2022 14:53:33 +0100

Adding bpf_cookie test for kprobe attached by fprobe link.

Signed-off-by: Jiri Olsa <[email-masked]>
---
 .../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