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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 | // SPDX-License-Identifier: GPL-2.0 /* * Basic test for sigtrap support. * * Copyright (C) 2021, Google LLC. */ #include <errno.h> #include <stdint.h> #include <stdlib.h> #include <linux/hw_breakpoint.h> #include <linux/string.h> #include <pthread.h> #include <signal.h> #include <sys/ioctl.h> #include <sys/syscall.h> #include <unistd.h> #include "cloexec.h" #include "debug.h" #include "event.h" #include "tests.h" #include "../perf-sys.h" #define NUM_THREADS 5 static struct { int tids_want_signal; /* Which threads still want a signal. */ int signal_count; /* Sanity check number of signals received. */ volatile int iterate_on; /* Variable to set breakpoint on. */ siginfo_t first_siginfo; /* First observed siginfo_t. */ } ctx; #define TEST_SIG_DATA (~(unsigned long)(&ctx.iterate_on)) static struct perf_event_attr make_event_attr(void) { struct perf_event_attr attr = { .type = PERF_TYPE_BREAKPOINT, .size = sizeof(attr), .sample_period = 1, .disabled = 1, .bp_addr = (unsigned long)&ctx.iterate_on, .bp_type = HW_BREAKPOINT_RW, .bp_len = HW_BREAKPOINT_LEN_1, .inherit = 1, /* Children inherit events ... */ .inherit_thread = 1, /* ... but only cloned with CLONE_THREAD. */ .remove_on_exec = 1, /* Required by sigtrap. */ .sigtrap = 1, /* Request synchronous SIGTRAP on event. */ .sig_data = TEST_SIG_DATA, .exclude_kernel = 1, /* To allow */ .exclude_hv = 1, /* running as !root */ }; return attr; } static void sigtrap_handler(int signum __maybe_unused, siginfo_t *info, void *ucontext __maybe_unused) { if (!__atomic_fetch_add(&ctx.signal_count, 1, __ATOMIC_RELAXED)) ctx.first_siginfo = *info; __atomic_fetch_sub(&ctx.tids_want_signal, syscall(SYS_gettid), __ATOMIC_RELAXED); } static void *test_thread(void *arg) { pthread_barrier_t *barrier = (pthread_barrier_t *)arg; pid_t tid = syscall(SYS_gettid); int i; pthread_barrier_wait(barrier); __atomic_fetch_add(&ctx.tids_want_signal, tid, __ATOMIC_RELAXED); for (i = 0; i < ctx.iterate_on - 1; i++) __atomic_fetch_add(&ctx.tids_want_signal, tid, __ATOMIC_RELAXED); return NULL; } static int run_test_threads(pthread_t *threads, pthread_barrier_t *barrier) { int i; pthread_barrier_wait(barrier); for (i = 0; i < NUM_THREADS; i++) TEST_ASSERT_EQUAL("pthread_join() failed", pthread_join(threads[i], NULL), 0); return TEST_OK; } static int run_stress_test(int fd, pthread_t *threads, pthread_barrier_t *barrier) { int ret; ctx.iterate_on = 3000; TEST_ASSERT_EQUAL("misfired signal?", ctx.signal_count, 0); TEST_ASSERT_EQUAL("enable failed", ioctl(fd, PERF_EVENT_IOC_ENABLE, 0), 0); ret = run_test_threads(threads, barrier); TEST_ASSERT_EQUAL("disable failed", ioctl(fd, PERF_EVENT_IOC_DISABLE, 0), 0); TEST_ASSERT_EQUAL("unexpected sigtraps", ctx.signal_count, NUM_THREADS * ctx.iterate_on); TEST_ASSERT_EQUAL("missing signals or incorrectly delivered", ctx.tids_want_signal, 0); TEST_ASSERT_VAL("unexpected si_addr", ctx.first_siginfo.si_addr == &ctx.iterate_on); #if 0 /* FIXME: enable when libc's signal.h has si_perf_{type,data} */ TEST_ASSERT_EQUAL("unexpected si_perf_type", ctx.first_siginfo.si_perf_type, PERF_TYPE_BREAKPOINT); TEST_ASSERT_EQUAL("unexpected si_perf_data", ctx.first_siginfo.si_perf_data, TEST_SIG_DATA); #endif return ret; } static int test__sigtrap(struct test_suite *test __maybe_unused, int subtest __maybe_unused) { struct perf_event_attr attr = make_event_attr(); struct sigaction action = {}; struct sigaction oldact; pthread_t threads[NUM_THREADS]; pthread_barrier_t barrier; char sbuf[STRERR_BUFSIZE]; int i, fd, ret = TEST_FAIL; if (!BP_SIGNAL_IS_SUPPORTED) { pr_debug("Test not supported on this architecture"); return TEST_SKIP; } pthread_barrier_init(&barrier, NULL, NUM_THREADS + 1); action.sa_flags = SA_SIGINFO | SA_NODEFER; action.sa_sigaction = sigtrap_handler; sigemptyset(&action.sa_mask); if (sigaction(SIGTRAP, &action, &oldact)) { pr_debug("FAILED sigaction(): %s\n", str_error_r(errno, sbuf, sizeof(sbuf))); goto out; } fd = sys_perf_event_open(&attr, 0, -1, -1, perf_event_open_cloexec_flag()); if (fd < 0) { pr_debug("FAILED sys_perf_event_open(): %s\n", str_error_r(errno, sbuf, sizeof(sbuf))); goto out_restore_sigaction; } for (i = 0; i < NUM_THREADS; i++) { if (pthread_create(&threads[i], NULL, test_thread, &barrier)) { pr_debug("FAILED pthread_create(): %s\n", str_error_r(errno, sbuf, sizeof(sbuf))); goto out_close_perf_event; } } ret = run_stress_test(fd, threads, &barrier); out_close_perf_event: close(fd); out_restore_sigaction: sigaction(SIGTRAP, &oldact, NULL); out: pthread_barrier_destroy(&barrier); return ret; } DEFINE_SUITE("Sigtrap", sigtrap); |