125 lines
3.2 KiB
C++
125 lines
3.2 KiB
C++
// RUN: %clang_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
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// Test case for recursive signal handlers, adopted from:
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// https://code.google.com/p/thread-sanitizer/issues/detail?id=71
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#include "test.h"
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#include <semaphore.h>
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#include <signal.h>
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#include <errno.h>
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static const int kSigSuspend = SIGUSR1;
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static const int kSigRestart = SIGUSR2;
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static sem_t g_thread_suspend_ack_sem;
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static bool g_busy_thread_received_restart;
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static volatile bool g_busy_thread_garbage_collected;
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static void SaveRegistersInStack() {
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// Mono walks thread stacks to detect unreferenced objects.
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// If last object reference is kept in register the object will be collected
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// This is why threads can't be suspended with something like pthread_suspend
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}
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static void fail(const char *what) {
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fprintf(stderr, "FAILED: %s (errno=%d)\n", what, errno);
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exit(1);
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}
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static void SuspendHandler(int sig) {
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int old_errno = errno;
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SaveRegistersInStack();
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// Enable kSigRestart handling, tsan disables signals around signal handlers.
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sigset_t sigset;
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sigemptyset(&sigset);
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pthread_sigmask(SIG_SETMASK, &sigset, 0);
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// Acknowledge that thread is saved and suspended
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if (sem_post(&g_thread_suspend_ack_sem) != 0)
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fail("sem_post failed");
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// Wait for wakeup signal.
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while (!g_busy_thread_received_restart)
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usleep(100); // wait for kSigRestart signal
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// Acknowledge that thread restarted
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if (sem_post(&g_thread_suspend_ack_sem) != 0)
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fail("sem_post failed");
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g_busy_thread_garbage_collected = true;
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errno = old_errno;
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}
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static void RestartHandler(int sig) {
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g_busy_thread_received_restart = true;
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}
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static void StopWorld(pthread_t thread) {
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if (pthread_kill(thread, kSigSuspend) != 0)
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fail("pthread_kill failed");
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while (sem_wait(&g_thread_suspend_ack_sem) != 0) {
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if (errno != EINTR)
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fail("sem_wait failed");
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}
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}
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static void StartWorld(pthread_t thread) {
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if (pthread_kill(thread, kSigRestart) != 0)
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fail("pthread_kill failed");
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while (sem_wait(&g_thread_suspend_ack_sem) != 0) {
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if (errno != EINTR)
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fail("sem_wait failed");
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}
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}
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static void CollectGarbage(pthread_t thread) {
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StopWorld(thread);
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// Walk stacks
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StartWorld(thread);
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}
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static void Init() {
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if (sem_init(&g_thread_suspend_ack_sem, 0, 0) != 0)
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fail("sem_init failed");
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struct sigaction act = {};
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act.sa_flags = SA_RESTART;
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act.sa_handler = &SuspendHandler;
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if (sigaction(kSigSuspend, &act, NULL) != 0)
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fail("sigaction failed");
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act.sa_handler = &RestartHandler;
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if (sigaction(kSigRestart, &act, NULL) != 0)
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fail("sigaction failed");
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}
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void* BusyThread(void *arg) {
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(void)arg;
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while (!g_busy_thread_garbage_collected) {
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usleep(100); // Tsan deadlocks without these sleeps
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}
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return NULL;
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}
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int main(int argc, const char *argv[]) {
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Init();
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pthread_t busy_thread;
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if (pthread_create(&busy_thread, NULL, &BusyThread, NULL) != 0)
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fail("pthread_create failed");
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CollectGarbage(busy_thread);
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if (pthread_join(busy_thread, 0) != 0)
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fail("pthread_join failed");
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fprintf(stderr, "DONE\n");
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return 0;
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}
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// CHECK-NOT: FAILED
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// CHECK-NOT: ThreadSanitizer CHECK failed
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// CHECK-NOT: WARNING: ThreadSanitizer:
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// CHECK: DONE
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