On 7/31/23 4:13 AM, Yafang Shao wrote:
Add selftest for the fill_link_info of uprobe, kprobe and tracepoint.
The result:
$ tools/testing/selftests/bpf/test_progs --name=fill_link_info
#79/1 fill_link_info/kprobe_link_info:OK
#79/2 fill_link_info/kretprobe_link_info:OK
#79/3 fill_link_info/kprobe_fill_invalid_user_buff:OK
#79/4 fill_link_info/tracepoint_link_info:OK
#79/5 fill_link_info/uprobe_link_info:OK
#79/6 fill_link_info/uretprobe_link_info:OK
#79/7 fill_link_info/kprobe_multi_link_info:OK
#79/8 fill_link_info/kretprobe_multi_link_info:OK
#79/9 fill_link_info/kprobe_multi_ubuff:OK
#79 fill_link_info:OK
Summary: 1/9 PASSED, 0 SKIPPED, 0 FAILED
The test case for kprobe_multi won't be run on aarch64, as it is not
supported.
Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
---
tools/testing/selftests/bpf/DENYLIST.aarch64 | 3 +
.../selftests/bpf/prog_tests/fill_link_info.c | 369 +++++++++++++++++++++
.../selftests/bpf/progs/test_fill_link_info.c | 42 +++
3 files changed, 414 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/fill_link_info.c
create mode 100644 tools/testing/selftests/bpf/progs/test_fill_link_info.c
diff --git a/tools/testing/selftests/bpf/DENYLIST.aarch64 b/tools/testing/selftests/bpf/DENYLIST.aarch64
index 3b61e8b..b2f46b6 100644
--- a/tools/testing/selftests/bpf/DENYLIST.aarch64
+++ b/tools/testing/selftests/bpf/DENYLIST.aarch64
@@ -12,3 +12,6 @@ kprobe_multi_test/skel_api # libbpf: failed to load BPF sk
module_attach # prog 'kprobe_multi': failed to auto-attach: -95
fentry_test/fentry_many_args # fentry_many_args:FAIL:fentry_many_args_attach unexpected error: -524
fexit_test/fexit_many_args # fexit_many_args:FAIL:fexit_many_args_attach unexpected error: -524
+fill_link_info/kprobe_multi_link_info # bpf_program__attach_kprobe_multi_opts unexpected error: -95
+fill_link_info/kretprobe_multi_link_info # bpf_program__attach_kprobe_multi_opts unexpected error: -95
+fill_link_info/kprobe_multi_ubuff # bpf_program__attach_kprobe_multi_opts unexpected error: -95
diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
new file mode 100644
index 0000000..948ae60
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
@@ -0,0 +1,369 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2023 Yafang Shao <laoar.shao@xxxxxxxxx> */
+
+#include <string.h>
+#include <linux/bpf.h>
+#include <linux/limits.h>
+#include <test_progs.h>
+#include "trace_helpers.h"
+#include "test_fill_link_info.skel.h"
+
+#define TP_CAT "sched"
+#define TP_NAME "sched_switch"
+#define KPROBE_FUNC "tcp_rcv_established"
+#define UPROBE_FILE "/proc/self/exe"
+#define KMULTI_CNT (4)
+
+/* uprobe attach point */
+static noinline void uprobe_func(void)
+{
+ asm volatile ("");
+}
+
+static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long addr,
+ ssize_t offset, ssize_t entry_offset)
+{
+ struct bpf_link_info info;
+ __u32 len = sizeof(info);
+ char buf[PATH_MAX];
+ int err = 0;
+
+ memset(&info, 0, sizeof(info));
+ buf[0] = '\0';
+
+again:
+ err = bpf_link_get_info_by_fd(fd, &info, &len);
+ if (!ASSERT_OK(err, "get_link_info"))
+ return -1;
+
+ switch (info.type) {
+ case BPF_LINK_TYPE_PERF_EVENT:
+ if (!ASSERT_EQ(info.perf_event.type, type, "perf_type_match"))
+ return -1;
+
+ switch (info.perf_event.type) {
+ case BPF_PERF_EVENT_KPROBE:
+ case BPF_PERF_EVENT_KRETPROBE:
+ ASSERT_EQ(info.perf_event.kprobe.offset, offset, "kprobe_offset");
+
+ /* In case kptr setting is not permitted or MAX_SYMS is reached */
'kptr' has special meaning in bpf ecosystem (searching verifier.c).
Could you re-word the above comments? I am not sure what it means.
+ if (addr)
+ ASSERT_EQ(info.perf_event.kprobe.addr, addr + entry_offset,
+ "kprobe_addr");
+
+ if (!info.perf_event.kprobe.func_name) {
+ ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len");
+ info.perf_event.kprobe.func_name = ptr_to_u64(&buf);
+ info.perf_event.kprobe.name_len = sizeof(buf);
+ goto again;
+ }
+
+ err = strncmp(u64_to_ptr(info.perf_event.kprobe.func_name), KPROBE_FUNC,
+ strlen(KPROBE_FUNC));
+ ASSERT_EQ(err, 0, "cmp_kprobe_func_name");
+ break;
+ case BPF_PERF_EVENT_TRACEPOINT:
+ if (!info.perf_event.tracepoint.tp_name) {
+ ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len");
+ info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf);
+ info.perf_event.tracepoint.name_len = sizeof(buf);
+ goto again;
+ }
+
+ err = strncmp(u64_to_ptr(info.perf_event.tracepoint.tp_name), TP_NAME,
+ strlen(TP_NAME));
+ ASSERT_EQ(err, 0, "cmp_tp_name");
+ break;
+ case BPF_PERF_EVENT_UPROBE:
+ case BPF_PERF_EVENT_URETPROBE:
+ ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
+
+ if (!info.perf_event.uprobe.file_name) {
+ ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len");
+ info.perf_event.uprobe.file_name = ptr_to_u64(&buf);
+ info.perf_event.uprobe.name_len = sizeof(buf);
+ goto again;
+ }
+
+ err = strncmp(u64_to_ptr(info.perf_event.uprobe.file_name), UPROBE_FILE,
+ strlen(UPROBE_FILE));
+ ASSERT_EQ(err, 0, "cmp_file_name");
+ break;
+ default:
+ break;
+ }
+ break;
+ default:
+ switch (type) {
+ case BPF_PERF_EVENT_KPROBE:
+ case BPF_PERF_EVENT_KRETPROBE:
+ case BPF_PERF_EVENT_TRACEPOINT:
+ case BPF_PERF_EVENT_UPROBE:
+ case BPF_PERF_EVENT_URETPROBE:
+ err = -1;
+ break;
+ default:
+ break;
+ }
+ break;
Is this whole 'default' thing ever possible?
Maybe you should have ASSERT_EQ(info.type, BPF_LINK_TYPE_PERF_EVENT)
first and then you won't need a top switch statement?
+ }
+ return err;
+}
+
+static void kprobe_fill_invalid_user_buffer(int fd)
+{
+ struct bpf_link_info info;
+ __u32 len = sizeof(info);
+ int err;
+
+ memset(&info, 0, sizeof(info));
+
+ info.perf_event.kprobe.func_name = 0x1; /* invalid address */
+ err = bpf_link_get_info_by_fd(fd, &info, &len);
+ ASSERT_EQ(err, -EINVAL, "invalid_buff_and_len");
+
+ info.perf_event.kprobe.name_len = 64;
+ err = bpf_link_get_info_by_fd(fd, &info, &len);
+ ASSERT_EQ(err, -EFAULT, "invalid_buff");
+
+ info.perf_event.kprobe.func_name = 0;
+ err = bpf_link_get_info_by_fd(fd, &info, &len);
+ ASSERT_EQ(err, -EINVAL, "invalid_len");
+
+ ASSERT_EQ(info.perf_event.kprobe.addr, 0, "func_addr");
+ ASSERT_EQ(info.perf_event.kprobe.offset, 0, "func_offset");
+ ASSERT_EQ(info.perf_event.type, 0, "type");
+}
+
+static void test_kprobe_fill_link_info(struct test_fill_link_info *skel,
+ enum bpf_perf_event_type type,
+ bool retprobe, bool invalid)
+{
+ DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts,
+ .attach_mode = PROBE_ATTACH_MODE_LINK,
+ .retprobe = retprobe,
+ );
+ ssize_t offset = 0, entry_offset = 0;
+ int link_fd, err;
+ long addr;
+
+ skel->links.kprobe_run = bpf_program__attach_kprobe_opts(skel->progs.kprobe_run,
+ KPROBE_FUNC, &opts);
+ if (!ASSERT_OK_PTR(skel->links.kprobe_run, "attach_kprobe"))
+ return;
+
+ link_fd = bpf_link__fd(skel->links.kprobe_run);
+ if (!ASSERT_GE(link_fd, 0, "link_fd"))
+ return;
There is no need to check validity of link_fd if skel->links.kprobe_run
is valid.
+
+ addr = ksym_get_addr(KPROBE_FUNC);
+ if (!invalid) {
+ /* See also arch_adjust_kprobe_addr(). */
+ if (skel->kconfig->CONFIG_X86_KERNEL_IBT)
+ entry_offset = 4;
+ err = verify_perf_link_info(link_fd, type, addr, offset, offset ?: entry_offset);
offset is always 0 here.
+ ASSERT_OK(err, "verify_perf_link_info");
+ } else {
+ kprobe_fill_invalid_user_buffer(link_fd);
+ }
+ bpf_link__detach(skel->links.kprobe_run);
+}
+
+static void test_tp_fill_link_info(struct test_fill_link_info *skel)
+{
+ int link_fd, err;
+
+ skel->links.tp_run = bpf_program__attach_tracepoint(skel->progs.tp_run, TP_CAT, TP_NAME);
+ if (!ASSERT_OK_PTR(skel->links.tp_run, "attach_tp"))
+ return;
+
+ link_fd = bpf_link__fd(skel->links.tp_run);
+ if (!ASSERT_GE(link_fd, 0, "link_fd"))
+ return;
No need to check link_fd.
+
+ err = verify_perf_link_info(link_fd, BPF_PERF_EVENT_TRACEPOINT, 0, 0, 0);
+ ASSERT_OK(err, "verify_perf_link_info");
+ bpf_link__detach(skel->links.tp_run);
+}
+
+static void test_uprobe_fill_link_info(struct test_fill_link_info *skel,
+ enum bpf_perf_event_type type, ssize_t offset,
+ bool retprobe)
+{
+ int link_fd, err;
+
+ skel->links.uprobe_run = bpf_program__attach_uprobe(skel->progs.uprobe_run, retprobe,
+ 0, /* self pid */
+ UPROBE_FILE, offset);
+ if (!ASSERT_OK_PTR(skel->links.uprobe_run, "attach_uprobe"))
+ return;
+
+ link_fd = bpf_link__fd(skel->links.uprobe_run);
+ if (!ASSERT_GE(link_fd, 0, "link_fd"))
+ return;
No need to check link_fd.
+
+ err = verify_perf_link_info(link_fd, type, 0, offset, 0);
+ ASSERT_OK(err, "verify_perf_link_info");
+ bpf_link__detach(skel->links.uprobe_run);
+}
+
+static int verify_kmulti_link_info(int fd, const __u64 *addrs, bool retprobe)
+{
+ __u64 kmulti_addrs[KMULTI_CNT];
+ struct bpf_link_info info;
+ __u32 len = sizeof(info);
+ int flags, i, err = 0;
+
+ memset(&info, 0, sizeof(info));
+
+again:
+ err = bpf_link_get_info_by_fd(fd, &info, &len);
+ if (!ASSERT_OK(err, "get_link_info"))
+ return -1;
+
+ ASSERT_EQ(info.type, BPF_LINK_TYPE_KPROBE_MULTI, "kmulti_type");
You can do
if (!ASSERT_EQ(info.type, BPF_LINK_TYPE_KPROBE_MULTI, "kmulti_type"))
return -1;
and then there is no need for below switch statement.
+ switch (info.type) {
+ case BPF_LINK_TYPE_KPROBE_MULTI:
+ ASSERT_EQ(info.kprobe_multi.count, KMULTI_CNT, "func_cnt");
+ flags = info.kprobe_multi.flags & BPF_F_KPROBE_MULTI_RETURN;
+ if (!retprobe)
+ ASSERT_EQ(flags, 0, "kmulti_flags");
+ else
+ ASSERT_NEQ(flags, 0, "kretmulti_flags");
+
+ if (!info.kprobe_multi.addrs) {
+ info.kprobe_multi.addrs = ptr_to_u64(kmulti_addrs);
+ goto again;
+ }
+ for (i = 0; i < KMULTI_CNT; i++)
+ ASSERT_EQ(kmulti_addrs[i], addrs[i], "kmulti_addrs");
+ break;
+ default:
+ err = -1;
+ break;
+ }
+ return err;
+}
+
+static void verify_kmulti_user_buffer(int fd, const __u64 *addrs)
+{
+ __u64 kmulti_addrs[KMULTI_CNT];
+ struct bpf_link_info info;
+ __u32 len = sizeof(info);
+ int err, i;
+
+ memset(&info, 0, sizeof(info));
+
+ info.kprobe_multi.count = KMULTI_CNT;
+ err = bpf_link_get_info_by_fd(fd, &info, &len);
+ ASSERT_EQ(err, -EINVAL, "no_addr");
+
+ info.kprobe_multi.addrs = ptr_to_u64(kmulti_addrs);
+ info.kprobe_multi.count = 0;
+ err = bpf_link_get_info_by_fd(fd, &info, &len);
+ ASSERT_EQ(err, -EINVAL, "no_cnt");
+
+ for (i = 0; i < KMULTI_CNT; i++)
+ kmulti_addrs[i] = 0;
+ info.kprobe_multi.count = KMULTI_CNT - 1;
+ err = bpf_link_get_info_by_fd(fd, &info, &len);
+ ASSERT_EQ(err, -ENOSPC, "smaller_cnt");
+ for (i = 0; i < KMULTI_CNT - 1; i++)
+ ASSERT_EQ(kmulti_addrs[i], addrs[i], "kmulti_addrs");
+ ASSERT_EQ(kmulti_addrs[i], 0, "kmulti_addrs");
+
+ for (i = 0; i < KMULTI_CNT; i++)
+ kmulti_addrs[i] = 0;
+ info.kprobe_multi.count = KMULTI_CNT + 1;
+ err = bpf_link_get_info_by_fd(fd, &info, &len);
+ ASSERT_EQ(err, 0, "bigger_cnt");
+ for (i = 0; i < KMULTI_CNT; i++)
+ ASSERT_EQ(kmulti_addrs[i], addrs[i], "kmulti_addrs");
+
+ info.kprobe_multi.count = KMULTI_CNT;
+ info.kprobe_multi.addrs = 0x1; /* invalid addr */
+ err = bpf_link_get_info_by_fd(fd, &info, &len);
+ ASSERT_EQ(err, -EFAULT, "invalid_buff");
+}
+
+static int symbols_cmp_r(const void *a, const void *b)
+{
+ const char **str_a = (const char **) a;
+ const char **str_b = (const char **) b;
+
+ return strcmp(*str_a, *str_b);
+}
+
+static void test_kprobe_multi_fill_link_info(struct test_fill_link_info *skel,
+ bool retprobe, bool buffer)
+{
+ LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);
+ const char *syms[KMULTI_CNT] = {
+ "schedule_timeout_interruptible",
+ "schedule_timeout_uninterruptible",
+ "schedule_timeout_idle",
+ "schedule_timeout_killable",
+ };
+ __u64 addrs[KMULTI_CNT];
+ int link_fd, i, err = 0;
+
+ qsort(syms, KMULTI_CNT, sizeof(syms[0]), symbols_cmp_r);
+ opts.syms = syms;
+ opts.cnt = KMULTI_CNT;
+ opts.retprobe = retprobe;
+ skel->links.kmulti_run = bpf_program__attach_kprobe_multi_opts(skel->progs.kmulti_run,
+ NULL, &opts);
+ if (!ASSERT_OK_PTR(skel->links.kmulti_run, "attach_kprobe_multi"))
+ return;
+
+ link_fd = bpf_link__fd(skel->links.kmulti_run);
+ if (!ASSERT_GE(link_fd, 0, "link_fd"))
+ return;
No need to check link_fd.
+
+ for (i = 0; i < KMULTI_CNT; i++)
+ addrs[i] = ksym_get_addr(syms[i]);
+
+ if (!buffer)
+ err = verify_kmulti_link_info(link_fd, addrs, retprobe);
+ else
+ verify_kmulti_user_buffer(link_fd, addrs);
+ ASSERT_OK(err, "verify_kmulti_link_info");
+ bpf_link__detach(skel->links.kmulti_run);
+}
+
+void test_fill_link_info(void)
+{
+ struct test_fill_link_info *skel;
+ ssize_t offset;
+
+ skel = test_fill_link_info__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "skel_open"))
+ goto cleanup;
Just return here if skel is invalid.
+
+ /* load kallsyms to compare the addr */
+ if (!ASSERT_OK(load_kallsyms_refresh(), "load_kallsyms_refresh"))
+ return;
You actually need to go to 'cleanup' here.
+ if (test__start_subtest("kprobe_link_info"))
+ test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KPROBE, false, false);
+ if (test__start_subtest("kretprobe_link_info"))
+ test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KRETPROBE, true, false);
+ if (test__start_subtest("kprobe_fill_invalid_user_buff"))
+ test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KPROBE, false, true);
+ if (test__start_subtest("tracepoint_link_info"))
+ test_tp_fill_link_info(skel);
+
+ offset = get_uprobe_offset(&uprobe_func);
+ if (test__start_subtest("uprobe_link_info"))
+ test_uprobe_fill_link_info(skel, BPF_PERF_EVENT_UPROBE, offset, false);
+ if (test__start_subtest("uretprobe_link_info"))
+ test_uprobe_fill_link_info(skel, BPF_PERF_EVENT_URETPROBE, offset, true);
+ if (test__start_subtest("kprobe_multi_link_info"))
+ test_kprobe_multi_fill_link_info(skel, false, false);
+ if (test__start_subtest("kretprobe_multi_link_info"))
+ test_kprobe_multi_fill_link_info(skel, true, false);
+ if (test__start_subtest("kprobe_multi_ubuff"))
+ test_kprobe_multi_fill_link_info(skel, true, true);
+
+cleanup:
+ test_fill_link_info__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_fill_link_info.c b/tools/testing/selftests/bpf/progs/test_fill_link_info.c
new file mode 100644
index 0000000..564f402
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_fill_link_info.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2023 Yafang Shao <laoar.shao@xxxxxxxxx> */
+
+#include "vmlinux.h"
+#include <bpf/bpf_tracing.h>
+#include <stdbool.h>
+
+extern bool CONFIG_X86_KERNEL_IBT __kconfig __weak;
+
+/* This function is here to have CONFIG_X86_KERNEL_IBT
+ * used and added to object BTF.
+ */
+int unused(void)
+{
+ return CONFIG_X86_KERNEL_IBT ? 0 : 1;
+}
+
+SEC("kprobe")
+int BPF_PROG(kprobe_run)
+{
+ return 0;
+}
+
+SEC("uprobe")
+int BPF_PROG(uprobe_run)
+{
+ return 0;
+}
+
+SEC("tracepoint")
+int BPF_PROG(tp_run)
+{
+ return 0;
+}
+
+SEC("kprobe.multi")
+int BPF_PROG(kmulti_run)
+{
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
