pthread_deadlock.m

#import <pthread.h>
 
static void unsafe_signal_handler (int signo) {
    /* Try to fetch thread names with the pthread API */
    char name[512];
    NSLog(@"Trying to use the pthread API from a signal handler. Is a deadlock coming?");
    pthread_getname_np(pthread_self(), name, sizeof(name));
      
    // We'll never reach this point. The process will stop here until the OS watchdog
    // kills it in 20+ seconds, or the user force quits it. No crash report (or a partial corrupt
    // one) will be written.
    NSLog(@"We'll never reach this point.");
  
    exit(1);
}
  
static void *enable_threading (void *ctx) {
    return NULL;
}
  
int main(int argc, char *argv[]) {
    /* Remove this line to test your own crash reporter */
    signal(SIGSEGV, unsafe_signal_handler);
 
    /* We have to use pthread_create() to enable locking in malloc/pthreads/etc -- this
     * would happen by default in any real application, as the standard frameworks
     * (such as dispatch) will trigger similar calls into the pthread APIs. */
    pthread_t thr;
    pthread_create(&thr, NULL, enable_threading, NULL);
 
    /* This is the actual code that triggers a reproducible deadlock; include this
     * in your own app to test a different crash reporter's behavior.
     *
     * While this is a simple test case to reliably trigger a deadlock, it's not necessary
     * to crash inside of a pthread call to trigger this bug. Any thread sitting inside of
     * pthread() at the time a crash occurs would trigger the same deadlock. */
    pthread_getname_np(pthread_self(), (char *)0x1, 1);     
 
    return 0;
}