tools/perf/tests/sigtrap.c

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