selftests/bpf: Augment send_signal test with remote signaling
Add testcases to test bpf_send_signal_task(). In these new test cases, the main process triggers the BPF program and the forked process receives the signals. The target process's signal handler receives a cookie from the bpf program. Signed-off-by: Puranjay Mohan <puranjay@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20241016084136.10305-3-puranjay@kernel.org
This commit is contained in:
Puranjay Mohan
committed by
Andrii Nakryiko
Andrii Nakryiko
parent
6280cf718d
commit
0e14189459
@@ -8,17 +8,25 @@ static int sigusr1_received;
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static void sigusr1_handler(int signum)
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{
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sigusr1_received = 1;
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sigusr1_received = 8;
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}
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static void sigusr1_siginfo_handler(int s, siginfo_t *i, void *v)
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{
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sigusr1_received = (int)(long long)i->si_value.sival_ptr;
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}
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static void test_send_signal_common(struct perf_event_attr *attr,
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bool signal_thread)
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bool signal_thread, bool remote)
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{
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struct test_send_signal_kern *skel;
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struct sigaction sa;
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int pipe_c2p[2], pipe_p2c[2];
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int err = -1, pmu_fd = -1;
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volatile int j = 0;
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char buf[256];
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pid_t pid;
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int old_prio;
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if (!ASSERT_OK(pipe(pipe_c2p), "pipe_c2p"))
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return;
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@@ -39,11 +47,14 @@ static void test_send_signal_common(struct perf_event_attr *attr,
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}
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if (pid == 0) {
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int old_prio;
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volatile int j = 0;
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/* install signal handler and notify parent */
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ASSERT_NEQ(signal(SIGUSR1, sigusr1_handler), SIG_ERR, "signal");
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if (remote) {
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sa.sa_sigaction = sigusr1_siginfo_handler;
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sa.sa_flags = SA_RESTART | SA_SIGINFO;
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ASSERT_NEQ(sigaction(SIGUSR1, &sa, NULL), -1, "sigaction");
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} else {
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ASSERT_NEQ(signal(SIGUSR1, sigusr1_handler), SIG_ERR, "signal");
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}
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close(pipe_c2p[0]); /* close read */
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close(pipe_p2c[1]); /* close write */
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@@ -52,10 +63,12 @@ static void test_send_signal_common(struct perf_event_attr *attr,
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* that if an interrupt happens, the underlying task
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* is this process.
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*/
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errno = 0;
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old_prio = getpriority(PRIO_PROCESS, 0);
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ASSERT_OK(errno, "getpriority");
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ASSERT_OK(setpriority(PRIO_PROCESS, 0, -20), "setpriority");
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if (!remote) {
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errno = 0;
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old_prio = getpriority(PRIO_PROCESS, 0);
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ASSERT_OK(errno, "getpriority");
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ASSERT_OK(setpriority(PRIO_PROCESS, 0, -20), "setpriority");
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}
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/* notify parent signal handler is installed */
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ASSERT_EQ(write(pipe_c2p[1], buf, 1), 1, "pipe_write");
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@@ -66,20 +79,25 @@ static void test_send_signal_common(struct perf_event_attr *attr,
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/* wait a little for signal handler */
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for (int i = 0; i < 1000000000 && !sigusr1_received; i++) {
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j /= i + j + 1;
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if (!attr)
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/* trigger the nanosleep tracepoint program. */
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usleep(1);
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if (remote)
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sleep(1);
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else
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if (!attr)
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/* trigger the nanosleep tracepoint program. */
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usleep(1);
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}
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buf[0] = sigusr1_received ? '2' : '0';
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ASSERT_EQ(sigusr1_received, 1, "sigusr1_received");
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buf[0] = sigusr1_received;
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ASSERT_EQ(sigusr1_received, 8, "sigusr1_received");
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ASSERT_EQ(write(pipe_c2p[1], buf, 1), 1, "pipe_write");
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/* wait for parent notification and exit */
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ASSERT_EQ(read(pipe_p2c[0], buf, 1), 1, "pipe_read");
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/* restore the old priority */
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ASSERT_OK(setpriority(PRIO_PROCESS, 0, old_prio), "setpriority");
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if (!remote)
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ASSERT_OK(setpriority(PRIO_PROCESS, 0, old_prio), "setpriority");
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close(pipe_c2p[1]);
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close(pipe_p2c[0]);
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@@ -93,6 +111,17 @@ static void test_send_signal_common(struct perf_event_attr *attr,
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if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
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goto skel_open_load_failure;
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/* boost with a high priority so we got a higher chance
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* that if an interrupt happens, the underlying task
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* is this process.
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*/
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if (remote) {
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errno = 0;
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old_prio = getpriority(PRIO_PROCESS, 0);
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ASSERT_OK(errno, "getpriority");
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ASSERT_OK(setpriority(PRIO_PROCESS, 0, -20), "setpriority");
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}
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if (!attr) {
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err = test_send_signal_kern__attach(skel);
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if (!ASSERT_OK(err, "skel_attach")) {
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@@ -100,8 +129,12 @@ static void test_send_signal_common(struct perf_event_attr *attr,
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goto destroy_skel;
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}
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} else {
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pmu_fd = syscall(__NR_perf_event_open, attr, pid, -1 /* cpu */,
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-1 /* group id */, 0 /* flags */);
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if (!remote)
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pmu_fd = syscall(__NR_perf_event_open, attr, pid, -1 /* cpu */,
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-1 /* group id */, 0 /* flags */);
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else
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pmu_fd = syscall(__NR_perf_event_open, attr, getpid(), -1 /* cpu */,
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-1 /* group id */, 0 /* flags */);
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if (!ASSERT_GE(pmu_fd, 0, "perf_event_open")) {
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err = -1;
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goto destroy_skel;
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@@ -119,11 +152,30 @@ static void test_send_signal_common(struct perf_event_attr *attr,
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/* trigger the bpf send_signal */
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skel->bss->signal_thread = signal_thread;
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skel->bss->sig = SIGUSR1;
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skel->bss->pid = pid;
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if (!remote) {
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skel->bss->target_pid = 0;
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skel->bss->pid = pid;
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} else {
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skel->bss->target_pid = pid;
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skel->bss->pid = getpid();
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}
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/* notify child that bpf program can send_signal now */
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ASSERT_EQ(write(pipe_p2c[1], buf, 1), 1, "pipe_write");
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/* For the remote test, the BPF program is triggered from this
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* process but the other process/thread is signaled.
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*/
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if (remote) {
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if (!attr) {
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for (int i = 0; i < 10; i++)
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usleep(1);
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} else {
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for (int i = 0; i < 100000000; i++)
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j /= i + 1;
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}
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}
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/* wait for result */
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err = read(pipe_c2p[0], buf, 1);
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if (!ASSERT_GE(err, 0, "reading pipe"))
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@@ -133,7 +185,7 @@ static void test_send_signal_common(struct perf_event_attr *attr,
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goto disable_pmu;
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}
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ASSERT_EQ(buf[0], '2', "incorrect result");
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ASSERT_EQ(buf[0], 8, "incorrect result");
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/* notify child safe to exit */
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ASSERT_EQ(write(pipe_p2c[1], buf, 1), 1, "pipe_write");
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@@ -142,18 +194,21 @@ disable_pmu:
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close(pmu_fd);
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destroy_skel:
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test_send_signal_kern__destroy(skel);
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/* restore the old priority */
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if (remote)
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ASSERT_OK(setpriority(PRIO_PROCESS, 0, old_prio), "setpriority");
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skel_open_load_failure:
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close(pipe_c2p[0]);
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close(pipe_p2c[1]);
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wait(NULL);
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}
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static void test_send_signal_tracepoint(bool signal_thread)
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static void test_send_signal_tracepoint(bool signal_thread, bool remote)
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{
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test_send_signal_common(NULL, signal_thread);
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test_send_signal_common(NULL, signal_thread, remote);
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}
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static void test_send_signal_perf(bool signal_thread)
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static void test_send_signal_perf(bool signal_thread, bool remote)
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{
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struct perf_event_attr attr = {
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.freq = 1,
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@@ -162,10 +217,10 @@ static void test_send_signal_perf(bool signal_thread)
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.config = PERF_COUNT_SW_CPU_CLOCK,
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};
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test_send_signal_common(&attr, signal_thread);
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test_send_signal_common(&attr, signal_thread, remote);
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}
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static void test_send_signal_nmi(bool signal_thread)
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static void test_send_signal_nmi(bool signal_thread, bool remote)
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{
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struct perf_event_attr attr = {
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.sample_period = 1,
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@@ -191,21 +246,35 @@ static void test_send_signal_nmi(bool signal_thread)
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close(pmu_fd);
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}
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test_send_signal_common(&attr, signal_thread);
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test_send_signal_common(&attr, signal_thread, remote);
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}
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void test_send_signal(void)
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{
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if (test__start_subtest("send_signal_tracepoint"))
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test_send_signal_tracepoint(false);
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test_send_signal_tracepoint(false, false);
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if (test__start_subtest("send_signal_perf"))
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test_send_signal_perf(false);
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test_send_signal_perf(false, false);
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if (test__start_subtest("send_signal_nmi"))
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test_send_signal_nmi(false);
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test_send_signal_nmi(false, false);
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if (test__start_subtest("send_signal_tracepoint_thread"))
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test_send_signal_tracepoint(true);
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test_send_signal_tracepoint(true, false);
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if (test__start_subtest("send_signal_perf_thread"))
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test_send_signal_perf(true);
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test_send_signal_perf(true, false);
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if (test__start_subtest("send_signal_nmi_thread"))
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test_send_signal_nmi(true);
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test_send_signal_nmi(true, false);
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/* Signal remote thread and thread group */
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if (test__start_subtest("send_signal_tracepoint_remote"))
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test_send_signal_tracepoint(false, true);
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if (test__start_subtest("send_signal_perf_remote"))
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test_send_signal_perf(false, true);
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if (test__start_subtest("send_signal_nmi_remote"))
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test_send_signal_nmi(false, true);
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if (test__start_subtest("send_signal_tracepoint_thread_remote"))
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test_send_signal_tracepoint(true, true);
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if (test__start_subtest("send_signal_perf_thread_remote"))
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test_send_signal_perf(true, true);
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if (test__start_subtest("send_signal_nmi_thread_remote"))
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test_send_signal_nmi(true, true);
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}
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@@ -1,27 +1,50 @@
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// SPDX-License-Identifier: GPL-2.0
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// Copyright (c) 2019 Facebook
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#include <linux/bpf.h>
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#include <vmlinux.h>
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#include <linux/version.h>
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#include <bpf/bpf_helpers.h>
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__u32 sig = 0, pid = 0, status = 0, signal_thread = 0;
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struct task_struct *bpf_task_from_pid(int pid) __ksym;
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void bpf_task_release(struct task_struct *p) __ksym;
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int bpf_send_signal_task(struct task_struct *task, int sig, enum pid_type type, u64 value) __ksym;
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__u32 sig = 0, pid = 0, status = 0, signal_thread = 0, target_pid = 0;
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static __always_inline int bpf_send_signal_test(void *ctx)
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{
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struct task_struct *target_task = NULL;
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int ret;
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u64 value;
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if (status != 0 || pid == 0)
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return 0;
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if ((bpf_get_current_pid_tgid() >> 32) == pid) {
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if (signal_thread)
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ret = bpf_send_signal_thread(sig);
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else
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ret = bpf_send_signal(sig);
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if (target_pid) {
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target_task = bpf_task_from_pid(target_pid);
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if (!target_task)
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return 0;
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value = 8;
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}
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if (signal_thread) {
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if (target_pid)
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ret = bpf_send_signal_task(target_task, sig, PIDTYPE_PID, value);
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else
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ret = bpf_send_signal_thread(sig);
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} else {
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if (target_pid)
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ret = bpf_send_signal_task(target_task, sig, PIDTYPE_TGID, value);
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else
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ret = bpf_send_signal(sig);
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}
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if (ret == 0)
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status = 1;
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}
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if (target_task)
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bpf_task_release(target_task);
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return 0;
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}
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