diff options
Diffstat (limited to '')
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/usdt.c | 419 |
1 files changed, 419 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/usdt.c b/tools/testing/selftests/bpf/prog_tests/usdt.c new file mode 100644 index 000000000000..9ad9da0f215e --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/usdt.c @@ -0,0 +1,419 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ +#include <test_progs.h> + +#define _SDT_HAS_SEMAPHORES 1 +#include "../sdt.h" + +#include "test_usdt.skel.h" +#include "test_urandom_usdt.skel.h" + +int lets_test_this(int); + +static volatile int idx = 2; +static volatile __u64 bla = 0xFEDCBA9876543210ULL; +static volatile short nums[] = {-1, -2, -3, -4}; + +static volatile struct { + int x; + signed char y; +} t1 = { 1, -127 }; + +#define SEC(name) __attribute__((section(name), used)) + +unsigned short test_usdt0_semaphore SEC(".probes"); +unsigned short test_usdt3_semaphore SEC(".probes"); +unsigned short test_usdt12_semaphore SEC(".probes"); + +static void __always_inline trigger_func(int x) { + long y = 42; + + if (test_usdt0_semaphore) + STAP_PROBE(test, usdt0); + if (test_usdt3_semaphore) + STAP_PROBE3(test, usdt3, x, y, &bla); + if (test_usdt12_semaphore) { + STAP_PROBE12(test, usdt12, + x, x + 1, y, x + y, 5, + y / 7, bla, &bla, -9, nums[x], + nums[idx], t1.y); + } +} + +static void subtest_basic_usdt(void) +{ + LIBBPF_OPTS(bpf_usdt_opts, opts); + struct test_usdt *skel; + struct test_usdt__bss *bss; + int err; + + skel = test_usdt__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + bss = skel->bss; + bss->my_pid = getpid(); + + err = test_usdt__attach(skel); + if (!ASSERT_OK(err, "skel_attach")) + goto cleanup; + + /* usdt0 won't be auto-attached */ + opts.usdt_cookie = 0xcafedeadbeeffeed; + skel->links.usdt0 = bpf_program__attach_usdt(skel->progs.usdt0, + 0 /*self*/, "/proc/self/exe", + "test", "usdt0", &opts); + if (!ASSERT_OK_PTR(skel->links.usdt0, "usdt0_link")) + goto cleanup; + + trigger_func(1); + + ASSERT_EQ(bss->usdt0_called, 1, "usdt0_called"); + ASSERT_EQ(bss->usdt3_called, 1, "usdt3_called"); + ASSERT_EQ(bss->usdt12_called, 1, "usdt12_called"); + + ASSERT_EQ(bss->usdt0_cookie, 0xcafedeadbeeffeed, "usdt0_cookie"); + ASSERT_EQ(bss->usdt0_arg_cnt, 0, "usdt0_arg_cnt"); + ASSERT_EQ(bss->usdt0_arg_ret, -ENOENT, "usdt0_arg_ret"); + + /* auto-attached usdt3 gets default zero cookie value */ + ASSERT_EQ(bss->usdt3_cookie, 0, "usdt3_cookie"); + ASSERT_EQ(bss->usdt3_arg_cnt, 3, "usdt3_arg_cnt"); + + ASSERT_EQ(bss->usdt3_arg_rets[0], 0, "usdt3_arg1_ret"); + ASSERT_EQ(bss->usdt3_arg_rets[1], 0, "usdt3_arg2_ret"); + ASSERT_EQ(bss->usdt3_arg_rets[2], 0, "usdt3_arg3_ret"); + ASSERT_EQ(bss->usdt3_args[0], 1, "usdt3_arg1"); + ASSERT_EQ(bss->usdt3_args[1], 42, "usdt3_arg2"); + ASSERT_EQ(bss->usdt3_args[2], (uintptr_t)&bla, "usdt3_arg3"); + + /* auto-attached usdt12 gets default zero cookie value */ + ASSERT_EQ(bss->usdt12_cookie, 0, "usdt12_cookie"); + ASSERT_EQ(bss->usdt12_arg_cnt, 12, "usdt12_arg_cnt"); + + ASSERT_EQ(bss->usdt12_args[0], 1, "usdt12_arg1"); + ASSERT_EQ(bss->usdt12_args[1], 1 + 1, "usdt12_arg2"); + ASSERT_EQ(bss->usdt12_args[2], 42, "usdt12_arg3"); + ASSERT_EQ(bss->usdt12_args[3], 42 + 1, "usdt12_arg4"); + ASSERT_EQ(bss->usdt12_args[4], 5, "usdt12_arg5"); + ASSERT_EQ(bss->usdt12_args[5], 42 / 7, "usdt12_arg6"); + ASSERT_EQ(bss->usdt12_args[6], bla, "usdt12_arg7"); + ASSERT_EQ(bss->usdt12_args[7], (uintptr_t)&bla, "usdt12_arg8"); + ASSERT_EQ(bss->usdt12_args[8], -9, "usdt12_arg9"); + ASSERT_EQ(bss->usdt12_args[9], nums[1], "usdt12_arg10"); + ASSERT_EQ(bss->usdt12_args[10], nums[idx], "usdt12_arg11"); + ASSERT_EQ(bss->usdt12_args[11], t1.y, "usdt12_arg12"); + + /* trigger_func() is marked __always_inline, so USDT invocations will be + * inlined in two different places, meaning that each USDT will have + * at least 2 different places to be attached to. This verifies that + * bpf_program__attach_usdt() handles this properly and attaches to + * all possible places of USDT invocation. + */ + trigger_func(2); + + ASSERT_EQ(bss->usdt0_called, 2, "usdt0_called"); + ASSERT_EQ(bss->usdt3_called, 2, "usdt3_called"); + ASSERT_EQ(bss->usdt12_called, 2, "usdt12_called"); + + /* only check values that depend on trigger_func()'s input value */ + ASSERT_EQ(bss->usdt3_args[0], 2, "usdt3_arg1"); + + ASSERT_EQ(bss->usdt12_args[0], 2, "usdt12_arg1"); + ASSERT_EQ(bss->usdt12_args[1], 2 + 1, "usdt12_arg2"); + ASSERT_EQ(bss->usdt12_args[3], 42 + 2, "usdt12_arg4"); + ASSERT_EQ(bss->usdt12_args[9], nums[2], "usdt12_arg10"); + + /* detach and re-attach usdt3 */ + bpf_link__destroy(skel->links.usdt3); + + opts.usdt_cookie = 0xBADC00C51E; + skel->links.usdt3 = bpf_program__attach_usdt(skel->progs.usdt3, -1 /* any pid */, + "/proc/self/exe", "test", "usdt3", &opts); + if (!ASSERT_OK_PTR(skel->links.usdt3, "usdt3_reattach")) + goto cleanup; + + trigger_func(3); + + ASSERT_EQ(bss->usdt3_called, 3, "usdt3_called"); + /* this time usdt3 has custom cookie */ + ASSERT_EQ(bss->usdt3_cookie, 0xBADC00C51E, "usdt3_cookie"); + ASSERT_EQ(bss->usdt3_arg_cnt, 3, "usdt3_arg_cnt"); + + ASSERT_EQ(bss->usdt3_arg_rets[0], 0, "usdt3_arg1_ret"); + ASSERT_EQ(bss->usdt3_arg_rets[1], 0, "usdt3_arg2_ret"); + ASSERT_EQ(bss->usdt3_arg_rets[2], 0, "usdt3_arg3_ret"); + ASSERT_EQ(bss->usdt3_args[0], 3, "usdt3_arg1"); + ASSERT_EQ(bss->usdt3_args[1], 42, "usdt3_arg2"); + ASSERT_EQ(bss->usdt3_args[2], (uintptr_t)&bla, "usdt3_arg3"); + +cleanup: + test_usdt__destroy(skel); +} + +unsigned short test_usdt_100_semaphore SEC(".probes"); +unsigned short test_usdt_300_semaphore SEC(".probes"); +unsigned short test_usdt_400_semaphore SEC(".probes"); + +#define R10(F, X) F(X+0); F(X+1);F(X+2); F(X+3); F(X+4); \ + F(X+5); F(X+6); F(X+7); F(X+8); F(X+9); +#define R100(F, X) R10(F,X+ 0);R10(F,X+10);R10(F,X+20);R10(F,X+30);R10(F,X+40); \ + R10(F,X+50);R10(F,X+60);R10(F,X+70);R10(F,X+80);R10(F,X+90); + +/* carefully control that we get exactly 100 inlines by preventing inlining */ +static void __always_inline f100(int x) +{ + STAP_PROBE1(test, usdt_100, x); +} + +__weak void trigger_100_usdts(void) +{ + R100(f100, 0); +} + +/* we shouldn't be able to attach to test:usdt2_300 USDT as we don't have as + * many slots for specs. It's important that each STAP_PROBE2() invocation + * (after untolling) gets different arg spec due to compiler inlining i as + * a constant + */ +static void __always_inline f300(int x) +{ + STAP_PROBE1(test, usdt_300, x); +} + +__weak void trigger_300_usdts(void) +{ + R100(f300, 0); + R100(f300, 100); + R100(f300, 200); +} + +static void __always_inline f400(int x __attribute__((unused))) +{ + STAP_PROBE1(test, usdt_400, 400); +} + +/* this time we have 400 different USDT call sites, but they have uniform + * argument location, so libbpf's spec string deduplication logic should keep + * spec count use very small and so we should be able to attach to all 400 + * call sites + */ +__weak void trigger_400_usdts(void) +{ + R100(f400, 0); + R100(f400, 100); + R100(f400, 200); + R100(f400, 300); +} + +static void subtest_multispec_usdt(void) +{ + LIBBPF_OPTS(bpf_usdt_opts, opts); + struct test_usdt *skel; + struct test_usdt__bss *bss; + int err, i; + + skel = test_usdt__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + bss = skel->bss; + bss->my_pid = getpid(); + + err = test_usdt__attach(skel); + if (!ASSERT_OK(err, "skel_attach")) + goto cleanup; + + /* usdt_100 is auto-attached and there are 100 inlined call sites, + * let's validate that all of them are properly attached to and + * handled from BPF side + */ + trigger_100_usdts(); + + ASSERT_EQ(bss->usdt_100_called, 100, "usdt_100_called"); + ASSERT_EQ(bss->usdt_100_sum, 99 * 100 / 2, "usdt_100_sum"); + + /* Stress test free spec ID tracking. By default libbpf allows up to + * 256 specs to be used, so if we don't return free spec IDs back + * after few detachments and re-attachments we should run out of + * available spec IDs. + */ + for (i = 0; i < 2; i++) { + bpf_link__destroy(skel->links.usdt_100); + + skel->links.usdt_100 = bpf_program__attach_usdt(skel->progs.usdt_100, -1, + "/proc/self/exe", + "test", "usdt_100", NULL); + if (!ASSERT_OK_PTR(skel->links.usdt_100, "usdt_100_reattach")) + goto cleanup; + + bss->usdt_100_sum = 0; + trigger_100_usdts(); + + ASSERT_EQ(bss->usdt_100_called, (i + 1) * 100 + 100, "usdt_100_called"); + ASSERT_EQ(bss->usdt_100_sum, 99 * 100 / 2, "usdt_100_sum"); + } + + /* Now let's step it up and try to attach USDT that requires more than + * 256 attach points with different specs for each. + * Note that we need trigger_300_usdts() only to actually have 300 + * USDT call sites, we are not going to actually trace them. + */ + trigger_300_usdts(); + + /* we'll reuse usdt_100 BPF program for usdt_300 test */ + bpf_link__destroy(skel->links.usdt_100); + skel->links.usdt_100 = bpf_program__attach_usdt(skel->progs.usdt_100, -1, "/proc/self/exe", + "test", "usdt_300", NULL); + err = -errno; + if (!ASSERT_ERR_PTR(skel->links.usdt_100, "usdt_300_bad_attach")) + goto cleanup; + ASSERT_EQ(err, -E2BIG, "usdt_300_attach_err"); + + /* let's check that there are no "dangling" BPF programs attached due + * to partial success of the above test:usdt_300 attachment + */ + bss->usdt_100_called = 0; + bss->usdt_100_sum = 0; + + f300(777); /* this is 301st instance of usdt_300 */ + + ASSERT_EQ(bss->usdt_100_called, 0, "usdt_301_called"); + ASSERT_EQ(bss->usdt_100_sum, 0, "usdt_301_sum"); + + /* This time we have USDT with 400 inlined invocations, but arg specs + * should be the same across all sites, so libbpf will only need to + * use one spec and thus we'll be able to attach 400 uprobes + * successfully. + * + * Again, we are reusing usdt_100 BPF program. + */ + skel->links.usdt_100 = bpf_program__attach_usdt(skel->progs.usdt_100, -1, + "/proc/self/exe", + "test", "usdt_400", NULL); + if (!ASSERT_OK_PTR(skel->links.usdt_100, "usdt_400_attach")) + goto cleanup; + + trigger_400_usdts(); + + ASSERT_EQ(bss->usdt_100_called, 400, "usdt_400_called"); + ASSERT_EQ(bss->usdt_100_sum, 400 * 400, "usdt_400_sum"); + +cleanup: + test_usdt__destroy(skel); +} + +static FILE *urand_spawn(int *pid) +{ + FILE *f; + + /* urandom_read's stdout is wired into f */ + f = popen("./urandom_read 1 report-pid", "r"); + if (!f) + return NULL; + + if (fscanf(f, "%d", pid) != 1) { + pclose(f); + return NULL; + } + + return f; +} + +static int urand_trigger(FILE **urand_pipe) +{ + int exit_code; + + /* pclose() waits for child process to exit and returns their exit code */ + exit_code = pclose(*urand_pipe); + *urand_pipe = NULL; + + return exit_code; +} + +static void subtest_urandom_usdt(bool auto_attach) +{ + struct test_urandom_usdt *skel; + struct test_urandom_usdt__bss *bss; + struct bpf_link *l; + FILE *urand_pipe = NULL; + int err, urand_pid = 0; + + skel = test_urandom_usdt__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + urand_pipe = urand_spawn(&urand_pid); + if (!ASSERT_OK_PTR(urand_pipe, "urand_spawn")) + goto cleanup; + + bss = skel->bss; + bss->urand_pid = urand_pid; + + if (auto_attach) { + err = test_urandom_usdt__attach(skel); + if (!ASSERT_OK(err, "skel_auto_attach")) + goto cleanup; + } else { + l = bpf_program__attach_usdt(skel->progs.urand_read_without_sema, + urand_pid, "./urandom_read", + "urand", "read_without_sema", NULL); + if (!ASSERT_OK_PTR(l, "urand_without_sema_attach")) + goto cleanup; + skel->links.urand_read_without_sema = l; + + l = bpf_program__attach_usdt(skel->progs.urand_read_with_sema, + urand_pid, "./urandom_read", + "urand", "read_with_sema", NULL); + if (!ASSERT_OK_PTR(l, "urand_with_sema_attach")) + goto cleanup; + skel->links.urand_read_with_sema = l; + + l = bpf_program__attach_usdt(skel->progs.urandlib_read_without_sema, + urand_pid, "./liburandom_read.so", + "urandlib", "read_without_sema", NULL); + if (!ASSERT_OK_PTR(l, "urandlib_without_sema_attach")) + goto cleanup; + skel->links.urandlib_read_without_sema = l; + + l = bpf_program__attach_usdt(skel->progs.urandlib_read_with_sema, + urand_pid, "./liburandom_read.so", + "urandlib", "read_with_sema", NULL); + if (!ASSERT_OK_PTR(l, "urandlib_with_sema_attach")) + goto cleanup; + skel->links.urandlib_read_with_sema = l; + + } + + /* trigger urandom_read USDTs */ + ASSERT_OK(urand_trigger(&urand_pipe), "urand_exit_code"); + + ASSERT_EQ(bss->urand_read_without_sema_call_cnt, 1, "urand_wo_sema_cnt"); + ASSERT_EQ(bss->urand_read_without_sema_buf_sz_sum, 256, "urand_wo_sema_sum"); + + ASSERT_EQ(bss->urand_read_with_sema_call_cnt, 1, "urand_w_sema_cnt"); + ASSERT_EQ(bss->urand_read_with_sema_buf_sz_sum, 256, "urand_w_sema_sum"); + + ASSERT_EQ(bss->urandlib_read_without_sema_call_cnt, 1, "urandlib_wo_sema_cnt"); + ASSERT_EQ(bss->urandlib_read_without_sema_buf_sz_sum, 256, "urandlib_wo_sema_sum"); + + ASSERT_EQ(bss->urandlib_read_with_sema_call_cnt, 1, "urandlib_w_sema_cnt"); + ASSERT_EQ(bss->urandlib_read_with_sema_buf_sz_sum, 256, "urandlib_w_sema_sum"); + +cleanup: + if (urand_pipe) + pclose(urand_pipe); + test_urandom_usdt__destroy(skel); +} + +void test_usdt(void) +{ + if (test__start_subtest("basic")) + subtest_basic_usdt(); + if (test__start_subtest("multispec")) + subtest_multispec_usdt(); + if (test__start_subtest("urand_auto_attach")) + subtest_urandom_usdt(true /* auto_attach */); + if (test__start_subtest("urand_pid_attach")) + subtest_urandom_usdt(false /* auto_attach */); +} |