Simulate MT unsafe issues https://github.com/libuv/libuv/issues/271

main.c

#include <assert.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <uv.h>


static int iterations = 0;


void *thread1() {
  int status = uv_set_process_title("Arizona");
  assert(status == 0);
  return NULL;
}


void *thread2() {
  char *buffer = (char *) malloc(sizeof(char) * 100);
  int status = uv_get_process_title(buffer, 100);
  assert(status == 0);

  if ((strcmp(buffer, "Arizona") != 0) &&
    (strcmp(buffer, "New York") != 0)) {

    printf("Incorrect result %s after %d iterations\n", buffer, iterations);
    exit(1);
  }

  return NULL;
}


int main(int argc, char** argv) {
  setbuf(stdout, NULL);

  uv_setup_args(argc, argv);

  int status;

  status = uv_set_process_title("New York");
  assert(status == 0);

  pthread_t t1;
  pthread_t t2;

  while(++iterations) {
    printf("\r%d iterations", iterations);

    pthread_create(&t2, NULL, thread2, NULL);
    pthread_create(&t1, NULL, thread1, NULL);

    pthread_join(t1, NULL);
    pthread_join(t2, NULL);

    status = uv_set_process_title("New York");
    assert(status == 0);

    if (iterations == 1e4) {
      printf("No failures after %f iterations", 1e4);
      exit(1);
    }
  }

  return 0;
}

If I run this with master I'll get following logged to console:

Incorrect result Neizona after 1859 iterations

Running with the branch in my PR, it will complete (10k iterations) without error.