On Fri, Jul 21, 2023 at 5:27 PM Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
>
> Add selftest for the fill_link_info of uprobe, kprobe and tracepoint.
> The result:
>
> #78/1 fill_link_info/kprobe_link_info:OK
> #78/2 fill_link_info/kretprobe_link_info:OK
> #78/3 fill_link_info/fill_invalid_user_buff:OK
> #78/4 fill_link_info/tracepoint_link_info:OK
> #78/5 fill_link_info/uprobe_link_info:OK
> #78/6 fill_link_info/uretprobe_link_info:OK
> #78 fill_link_info:OK
> Summary: 1/6 PASSED, 0 SKIPPED, 0 FAILED
>
> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> ---
> .../selftests/bpf/prog_tests/fill_link_info.c | 232 +++++++++++++++++++++
> .../selftests/bpf/progs/test_fill_link_info.c | 25 +++
> 2 files changed, 257 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/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
> new file mode 100644
> index 0000000..9779a8a
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
> @@ -0,0 +1,232 @@
> +// 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"
> +
> +/* uprobe attach point */
> +static noinline void uprobe_func(void)
> +{
> + asm volatile ("");
> +}
> +
> +static int verify_link_info(int fd, enum bpf_perf_event_type type, long addr, ssize_t 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 */
> + if (addr)
> + ASSERT_EQ(info.perf_event.kprobe.addr, addr, "kprobe_addr");
The BPF CI failed due to this assertion. Because the 4 Bytes ENDBR
instructions are added into the function entry, in which case
info.perf_event.kprobe.addr will be (addr + 4).
Will improve this test case in the next version.
> +
> + 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;
> + }
> + return err;
> +}
> +
> +static void kprobe_fill_invalid_user_buffer(int fd)
> +{
> + struct bpf_link_info info;
> + __u32 len = sizeof(info);
> + int err = 0;
> +
> + 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,
> + );
> + 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;
> +
> + addr = ksym_get_addr(KPROBE_FUNC);
> + if (!invalid) {
> + err = verify_link_info(link_fd, type, addr, 0);
> + ASSERT_OK(err, "verify_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;
> +
> + err = verify_link_info(link_fd, BPF_PERF_EVENT_TRACEPOINT, 0, 0);
> + ASSERT_OK(err, "verify_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;
> +
> + err = verify_link_info(link_fd, type, 0, offset);
> + ASSERT_OK(err, "verify_link_info");
> + bpf_link__detach(skel->links.uprobe_run);
> +}
> +
> +void serial_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;
> +
> + /* load kallsyms to compare the addr */
> + if (!ASSERT_OK(load_kallsyms_refresh(), "load_kallsyms_refresh"))
> + return;
> + 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("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);
> +
> +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..f776134
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/test_fill_link_info.c
> @@ -0,0 +1,25 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (C) 2023 Yafang Shao <laoar.shao@xxxxxxxxx> */
> +
> +#include "vmlinux.h"
> +#include <bpf/bpf_tracing.h>
> +
> +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;
> +}
> +
> +char _license[] SEC("license") = "GPL";
> --
> 1.8.3.1
>
--
Regards
Yafang
