1 // SPDX-License-Identifier: GPL-2.0 2 #include <test_progs.h> 3 #include <sys/time.h> 4 #include <sys/resource.h> 5 #include "test_send_signal_kern.skel.h" 6 7 static int sigusr1_received; 8 9 static void sigusr1_handler(int signum) 10 { 11 sigusr1_received = 1; 12 } 13 14 static void test_send_signal_common(struct perf_event_attr *attr, 15 bool signal_thread) 16 { 17 struct test_send_signal_kern *skel; 18 int pipe_c2p[2], pipe_p2c[2]; 19 int err = -1, pmu_fd = -1; 20 char buf[256]; 21 pid_t pid; 22 23 if (!ASSERT_OK(pipe(pipe_c2p), "pipe_c2p")) 24 return; 25 26 if (!ASSERT_OK(pipe(pipe_p2c), "pipe_p2c")) { 27 close(pipe_c2p[0]); 28 close(pipe_c2p[1]); 29 return; 30 } 31 32 pid = fork(); 33 if (!ASSERT_GE(pid, 0, "fork")) { 34 close(pipe_c2p[0]); 35 close(pipe_c2p[1]); 36 close(pipe_p2c[0]); 37 close(pipe_p2c[1]); 38 return; 39 } 40 41 if (pid == 0) { 42 int old_prio; 43 volatile int j = 0; 44 45 /* install signal handler and notify parent */ 46 ASSERT_NEQ(signal(SIGUSR1, sigusr1_handler), SIG_ERR, "signal"); 47 48 close(pipe_c2p[0]); /* close read */ 49 close(pipe_p2c[1]); /* close write */ 50 51 /* boost with a high priority so we got a higher chance 52 * that if an interrupt happens, the underlying task 53 * is this process. 54 */ 55 errno = 0; 56 old_prio = getpriority(PRIO_PROCESS, 0); 57 ASSERT_OK(errno, "getpriority"); 58 ASSERT_OK(setpriority(PRIO_PROCESS, 0, -20), "setpriority"); 59 60 /* notify parent signal handler is installed */ 61 ASSERT_EQ(write(pipe_c2p[1], buf, 1), 1, "pipe_write"); 62 63 /* make sure parent enabled bpf program to send_signal */ 64 ASSERT_EQ(read(pipe_p2c[0], buf, 1), 1, "pipe_read"); 65 66 /* wait a little for signal handler */ 67 for (int i = 0; i < 1000000000 && !sigusr1_received; i++) { 68 j /= i + j + 1; 69 if (!attr) 70 /* trigger the nanosleep tracepoint program. */ 71 usleep(1); 72 } 73 74 buf[0] = sigusr1_received ? '2' : '0'; 75 ASSERT_EQ(sigusr1_received, 1, "sigusr1_received"); 76 ASSERT_EQ(write(pipe_c2p[1], buf, 1), 1, "pipe_write"); 77 78 /* wait for parent notification and exit */ 79 ASSERT_EQ(read(pipe_p2c[0], buf, 1), 1, "pipe_read"); 80 81 /* restore the old priority */ 82 ASSERT_OK(setpriority(PRIO_PROCESS, 0, old_prio), "setpriority"); 83 84 close(pipe_c2p[1]); 85 close(pipe_p2c[0]); 86 exit(0); 87 } 88 89 close(pipe_c2p[1]); /* close write */ 90 close(pipe_p2c[0]); /* close read */ 91 92 skel = test_send_signal_kern__open_and_load(); 93 if (!ASSERT_OK_PTR(skel, "skel_open_and_load")) 94 goto skel_open_load_failure; 95 96 if (!attr) { 97 err = test_send_signal_kern__attach(skel); 98 if (!ASSERT_OK(err, "skel_attach")) { 99 err = -1; 100 goto destroy_skel; 101 } 102 } else { 103 pmu_fd = syscall(__NR_perf_event_open, attr, pid, -1 /* cpu */, 104 -1 /* group id */, 0 /* flags */); 105 if (!ASSERT_GE(pmu_fd, 0, "perf_event_open")) { 106 err = -1; 107 goto destroy_skel; 108 } 109 110 skel->links.send_signal_perf = 111 bpf_program__attach_perf_event(skel->progs.send_signal_perf, pmu_fd); 112 if (!ASSERT_OK_PTR(skel->links.send_signal_perf, "attach_perf_event")) 113 goto disable_pmu; 114 } 115 116 /* wait until child signal handler installed */ 117 ASSERT_EQ(read(pipe_c2p[0], buf, 1), 1, "pipe_read"); 118 119 /* trigger the bpf send_signal */ 120 skel->bss->signal_thread = signal_thread; 121 skel->bss->sig = SIGUSR1; 122 skel->bss->pid = pid; 123 124 /* notify child that bpf program can send_signal now */ 125 ASSERT_EQ(write(pipe_p2c[1], buf, 1), 1, "pipe_write"); 126 127 /* wait for result */ 128 err = read(pipe_c2p[0], buf, 1); 129 if (!ASSERT_GE(err, 0, "reading pipe")) 130 goto disable_pmu; 131 if (!ASSERT_GT(err, 0, "reading pipe error: size 0")) { 132 err = -1; 133 goto disable_pmu; 134 } 135 136 ASSERT_EQ(buf[0], '2', "incorrect result"); 137 138 /* notify child safe to exit */ 139 ASSERT_EQ(write(pipe_p2c[1], buf, 1), 1, "pipe_write"); 140 141 disable_pmu: 142 close(pmu_fd); 143 destroy_skel: 144 test_send_signal_kern__destroy(skel); 145 skel_open_load_failure: 146 close(pipe_c2p[0]); 147 close(pipe_p2c[1]); 148 wait(NULL); 149 } 150 151 static void test_send_signal_tracepoint(bool signal_thread) 152 { 153 test_send_signal_common(NULL, signal_thread); 154 } 155 156 static void test_send_signal_perf(bool signal_thread) 157 { 158 struct perf_event_attr attr = { 159 .sample_period = 1, 160 .type = PERF_TYPE_SOFTWARE, 161 .config = PERF_COUNT_SW_CPU_CLOCK, 162 }; 163 164 test_send_signal_common(&attr, signal_thread); 165 } 166 167 static void test_send_signal_nmi(bool signal_thread) 168 { 169 struct perf_event_attr attr = { 170 .sample_period = 1, 171 .type = PERF_TYPE_HARDWARE, 172 .config = PERF_COUNT_HW_CPU_CYCLES, 173 }; 174 int pmu_fd; 175 176 /* Some setups (e.g. virtual machines) might run with hardware 177 * perf events disabled. If this is the case, skip this test. 178 */ 179 pmu_fd = syscall(__NR_perf_event_open, &attr, 0 /* pid */, 180 -1 /* cpu */, -1 /* group_fd */, 0 /* flags */); 181 if (pmu_fd == -1) { 182 if (errno == ENOENT) { 183 printf("%s:SKIP:no PERF_COUNT_HW_CPU_CYCLES\n", 184 __func__); 185 test__skip(); 186 return; 187 } 188 /* Let the test fail with a more informative message */ 189 } else { 190 close(pmu_fd); 191 } 192 193 test_send_signal_common(&attr, signal_thread); 194 } 195 196 void test_send_signal(void) 197 { 198 if (test__start_subtest("send_signal_tracepoint")) 199 test_send_signal_tracepoint(false); 200 if (test__start_subtest("send_signal_perf")) 201 test_send_signal_perf(false); 202 if (test__start_subtest("send_signal_nmi")) 203 test_send_signal_nmi(false); 204 if (test__start_subtest("send_signal_tracepoint_thread")) 205 test_send_signal_tracepoint(true); 206 if (test__start_subtest("send_signal_perf_thread")) 207 test_send_signal_perf(true); 208 if (test__start_subtest("send_signal_nmi_thread")) 209 test_send_signal_nmi(true); 210 } 211