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laoarKernel Patches Daemon
laoar
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selftests/bpf: Add selftest for fill_link_info
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 <[email protected]>
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‎tools/testing/selftests/bpf/prog_tests/fill_link_info.c

Lines changed: 238 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (C) 2023 Yafang Shao <[email protected]> */
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#include <string.h>
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#include <linux/bpf.h>
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#include <linux/limits.h>
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#include <test_progs.h>
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#include "trace_helpers.h"
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#include "test_fill_link_info.skel.h"
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#define TP_CAT "sched"
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#define TP_NAME "sched_switch"
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#define KPROBE_FUNC "tcp_rcv_established"
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#define UPROBE_FILE "/proc/self/exe"
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/* uprobe attach point */
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static noinline void uprobe_func(void)
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{
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asm volatile ("");
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}
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static int verify_link_info(int fd, enum bpf_perf_event_type type, long addr, ssize_t offset)
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{
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struct bpf_link_info info;
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__u32 len = sizeof(info);
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char buf[PATH_MAX];
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int err = 0;
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memset(&info, 0, sizeof(info));
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buf[0] = '\0';
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again:
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err = bpf_link_get_info_by_fd(fd, &info, &len);
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if (!ASSERT_OK(err, "get_link_info"))
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return -1;
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switch (info.type) {
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case BPF_LINK_TYPE_PERF_EVENT:
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if (!ASSERT_EQ(info.perf_event.type, type, "perf_type_match"))
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return -1;
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switch (info.perf_event.type) {
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case BPF_PERF_EVENT_KPROBE:
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case BPF_PERF_EVENT_KRETPROBE:
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ASSERT_EQ(info.perf_event.kprobe.offset, offset, "kprobe_offset");
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/* In case kptr setting is not permitted or MAX_SYMS is reached */
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if (addr) {
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long addrs[2] = {
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addr + offset,
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addr + 0x4, /* For ENDBDR */
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};
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ASSERT_IN_ARRAY(info.perf_event.kprobe.addr, addrs, "kprobe_addr");
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}
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if (!info.perf_event.kprobe.func_name) {
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ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len");
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info.perf_event.kprobe.func_name = ptr_to_u64(&buf);
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info.perf_event.kprobe.name_len = sizeof(buf);
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goto again;
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}
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err = strncmp(u64_to_ptr(info.perf_event.kprobe.func_name), KPROBE_FUNC,
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strlen(KPROBE_FUNC));
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ASSERT_EQ(err, 0, "cmp_kprobe_func_name");
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break;
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case BPF_PERF_EVENT_TRACEPOINT:
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if (!info.perf_event.tracepoint.tp_name) {
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ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len");
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info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf);
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info.perf_event.tracepoint.name_len = sizeof(buf);
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goto again;
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}
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err = strncmp(u64_to_ptr(info.perf_event.tracepoint.tp_name), TP_NAME,
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strlen(TP_NAME));
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ASSERT_EQ(err, 0, "cmp_tp_name");
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break;
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case BPF_PERF_EVENT_UPROBE:
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case BPF_PERF_EVENT_URETPROBE:
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ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
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if (!info.perf_event.uprobe.file_name) {
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ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len");
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info.perf_event.uprobe.file_name = ptr_to_u64(&buf);
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info.perf_event.uprobe.name_len = sizeof(buf);
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goto again;
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}
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err = strncmp(u64_to_ptr(info.perf_event.uprobe.file_name), UPROBE_FILE,
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strlen(UPROBE_FILE));
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ASSERT_EQ(err, 0, "cmp_file_name");
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break;
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default:
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break;
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}
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break;
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default:
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switch (type) {
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case BPF_PERF_EVENT_KPROBE:
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case BPF_PERF_EVENT_KRETPROBE:
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case BPF_PERF_EVENT_TRACEPOINT:
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case BPF_PERF_EVENT_UPROBE:
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case BPF_PERF_EVENT_URETPROBE:
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err = -1;
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break;
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default:
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break;
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}
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break;
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}
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return err;
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}
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static void kprobe_fill_invalid_user_buffer(int fd)
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{
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struct bpf_link_info info;
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__u32 len = sizeof(info);
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int err = 0;
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memset(&info, 0, sizeof(info));
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info.perf_event.kprobe.func_name = 0x1; /* invalid address */
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err = bpf_link_get_info_by_fd(fd, &info, &len);
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ASSERT_EQ(err, -EINVAL, "invalid_buff_and_len");
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info.perf_event.kprobe.name_len = 64;
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err = bpf_link_get_info_by_fd(fd, &info, &len);
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ASSERT_EQ(err, -EFAULT, "invalid_buff");
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info.perf_event.kprobe.func_name = 0;
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err = bpf_link_get_info_by_fd(fd, &info, &len);
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ASSERT_EQ(err, -EINVAL, "invalid_len");
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ASSERT_EQ(info.perf_event.kprobe.addr, 0, "func_addr");
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ASSERT_EQ(info.perf_event.kprobe.offset, 0, "func_offset");
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ASSERT_EQ(info.perf_event.type, 0, "type");
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}
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static void test_kprobe_fill_link_info(struct test_fill_link_info *skel,
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enum bpf_perf_event_type type,
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bool retprobe, bool invalid)
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{
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DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts,
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.attach_mode = PROBE_ATTACH_MODE_LINK,
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.retprobe = retprobe,
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);
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int link_fd, err;
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long addr;
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skel->links.kprobe_run = bpf_program__attach_kprobe_opts(skel->progs.kprobe_run,
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KPROBE_FUNC, &opts);
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if (!ASSERT_OK_PTR(skel->links.kprobe_run, "attach_kprobe"))
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return;
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link_fd = bpf_link__fd(skel->links.kprobe_run);
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if (!ASSERT_GE(link_fd, 0, "link_fd"))
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return;
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addr = ksym_get_addr(KPROBE_FUNC);
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if (!invalid) {
163+
err = verify_link_info(link_fd, type, addr, 0);
164+
ASSERT_OK(err, "verify_link_info");
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} else {
166+
kprobe_fill_invalid_user_buffer(link_fd);
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}
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bpf_link__detach(skel->links.kprobe_run);
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}
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static void test_tp_fill_link_info(struct test_fill_link_info *skel)
172+
{
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int link_fd, err;
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175+
skel->links.tp_run = bpf_program__attach_tracepoint(skel->progs.tp_run, TP_CAT, TP_NAME);
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if (!ASSERT_OK_PTR(skel->links.tp_run, "attach_tp"))
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return;
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link_fd = bpf_link__fd(skel->links.tp_run);
180+
if (!ASSERT_GE(link_fd, 0, "link_fd"))
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return;
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183+
err = verify_link_info(link_fd, BPF_PERF_EVENT_TRACEPOINT, 0, 0);
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ASSERT_OK(err, "verify_link_info");
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bpf_link__detach(skel->links.tp_run);
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}
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static void test_uprobe_fill_link_info(struct test_fill_link_info *skel,
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enum bpf_perf_event_type type, ssize_t offset,
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bool retprobe)
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{
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int link_fd, err;
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skel->links.uprobe_run = bpf_program__attach_uprobe(skel->progs.uprobe_run, retprobe,
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0, /* self pid */
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UPROBE_FILE, offset);
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if (!ASSERT_OK_PTR(skel->links.uprobe_run, "attach_uprobe"))
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return;
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link_fd = bpf_link__fd(skel->links.uprobe_run);
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if (!ASSERT_GE(link_fd, 0, "link_fd"))
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return;
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err = verify_link_info(link_fd, type, 0, offset);
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ASSERT_OK(err, "verify_link_info");
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bpf_link__detach(skel->links.uprobe_run);
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}
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void serial_test_fill_link_info(void)
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{
211+
struct test_fill_link_info *skel;
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ssize_t offset;
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skel = test_fill_link_info__open_and_load();
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if (!ASSERT_OK_PTR(skel, "skel_open"))
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goto cleanup;
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/* load kallsyms to compare the addr */
219+
if (!ASSERT_OK(load_kallsyms_refresh(), "load_kallsyms_refresh"))
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return;
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if (test__start_subtest("kprobe_link_info"))
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test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KPROBE, false, false);
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if (test__start_subtest("kretprobe_link_info"))
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test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KRETPROBE, true, false);
225+
if (test__start_subtest("fill_invalid_user_buff"))
226+
test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KPROBE, false, true);
227+
if (test__start_subtest("tracepoint_link_info"))
228+
test_tp_fill_link_info(skel);
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230+
offset = get_uprobe_offset(&uprobe_func);
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if (test__start_subtest("uprobe_link_info"))
232+
test_uprobe_fill_link_info(skel, BPF_PERF_EVENT_UPROBE, offset, false);
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if (test__start_subtest("uretprobe_link_info"))
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test_uprobe_fill_link_info(skel, BPF_PERF_EVENT_URETPROBE, offset, true);
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cleanup:
237+
test_fill_link_info__destroy(skel);
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}

‎tools/testing/selftests/bpf/progs/test_fill_link_info.c

Lines changed: 25 additions & 0 deletions
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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (C) 2023 Yafang Shao <[email protected]> */
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#include "vmlinux.h"
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#include <bpf/bpf_tracing.h>
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SEC("kprobe")
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int BPF_PROG(kprobe_run)
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{
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return 0;
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}
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SEC("uprobe")
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int BPF_PROG(uprobe_run)
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{
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return 0;
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}
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SEC("tracepoint")
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int BPF_PROG(tp_run)
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{
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return 0;
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}
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char _license[] SEC("license") = "GPL";

‎tools/testing/selftests/bpf/test_progs.h

Lines changed: 19 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -300,6 +300,25 @@ int test__join_cgroup(const char *path);
300300
___ok; \
301301
})
302302

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#define ASSERT_IN_ARRAY(actual, expected, name) ({ \
304+
static int duration; \
305+
typeof(actual) ___act = (actual); \
306+
typeof((expected)[0]) * ___exp = (expected); \
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bool ___ok = false; \
308+
int i; \
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\
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for (i = 0; i < ARRAY_SIZE(expected); i++) { \
311+
if (___act == ___exp[i]) { \
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___ok = true; \
313+
break; \
314+
} \
315+
} \
316+
CHECK(!___ok, (name), \
317+
"unexpected %s: actual %lld not in array\n", \
318+
(name), (long long)(___act)); \
319+
___ok; \
320+
})
321+
303322
#define ASSERT_STREQ(actual, expected, name) ({ \
304323
static int duration = 0; \
305324
const char *___act = actual; \

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