Demonstrate signal safety of recursive mutexes

Author: jart

test/posix/exit_async_signal_safety_test.c

@@ -0,0 +1,30 @@
+#include <pthread.h>
+#include <stdatomic.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+atomic_bool ready;
+
+void* work(void* arg) {
+  pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, 0);
+  ready = true;
+  pthread_exit(0);
+}
+
+int main() {
+
+  for (int i = 0; i < 1000; ++i) {
+    pthread_t th;
+    if (pthread_create(&th, 0, work, 0))
+      _Exit(1);
+    for (;;)
+      if (ready)
+        break;
+    pthread_cancel(th);
+    if (pthread_join(th, 0))
+      _Exit(3);
+  }
+
+  while (!pthread_orphan_np())
+    pthread_decimate_np();
+}

test/posix/mutex_async_signal_safety_test.c

@@ -0,0 +1,82 @@
+#include <pthread.h>
+#include <signal.h>
+#include <stdatomic.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+// tests that recursive mutexes are implemented atomically
+//
+// glibc fails this test
+
+atomic_bool done;
+atomic_bool ready;
+pthread_mutex_t lock;
+
+void hand(int sig) {
+  if (pthread_mutex_lock(&lock))
+    _Exit(50);
+  if (pthread_mutex_unlock(&lock))
+    _Exit(51);
+}
+
+void* work(void* arg) {
+  ready = true;
+  while (!done) {
+    if (pthread_mutex_lock(&lock))
+      _Exit(60);
+    if (pthread_mutex_unlock(&lock))
+      _Exit(61);
+  }
+  return 0;
+}
+
+int main() {
+
+  struct sigaction sa;
+  sa.sa_handler = hand;
+  sa.sa_flags = SA_NODEFER;
+  sigemptyset(&sa.sa_mask);
+  if (sigaction(SIGUSR1, &sa, 0))
+    _Exit(1);
+
+  pthread_mutexattr_t attr;
+  if (pthread_mutexattr_init(&attr))
+    _Exit(2);
+  if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE))
+    _Exit(3);
+  if (pthread_mutex_init(&lock, &attr))
+    _Exit(4);
+  if (pthread_mutexattr_destroy(&attr))
+    _Exit(5);
+
+  pthread_t th;
+  pthread_attr_t tattr;
+  if (pthread_attr_init(&tattr))
+    _Exit(6);
+  if (pthread_attr_setstacksize(&tattr, 8 * 1024 * 1024))
+    _Exit(7);
+  if (pthread_attr_setguardsize(&tattr, 64 * 1024))
+    _Exit(8);
+  if (pthread_create(&th, &tattr, work, 0))
+    _Exit(9);
+  if (pthread_attr_destroy(&tattr))
+    _Exit(10);
+  for (;;)
+    if (ready)
+      break;
+
+  for (int i = 0; i < 1000; ++i) {
+    if (pthread_kill(th, SIGUSR1))
+      _Exit(11);
+    if (pthread_kill(th, SIGUSR1))
+      _Exit(12);
+    usleep(1);
+  }
+
+  done = true;
+  if (pthread_join(th, 0))
+    _Exit(13);
+  if (pthread_mutex_destroy(&lock))
+    _Exit(14);
+}