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