Month: April 2025

I was curious whether pthread_spin_lock() can really detect deadlock scenario, so I wrote a simple program to test:

#include <stdio.h>
#include <pthread.h>

int
main(void)
{
    pthread_spinlock_t lock;
    if (pthread_spin_init(&lock, PTHREAD_PROCESS_PRIVATE) != 0) {
        perror("pthread_spin_init error");
        return 1;
    }

    if (pthread_spin_lock(&lock) != 0) {
        perror("pthread_spin_lock 1 error");
        return 1;
    }

    if (pthread_spin_lock(&lock) != 0) {
        perror("pthread_spin_lock 2 error");
        return 1;
    }

    return 0;
}

Tested it on both Linux and FreeBSD, the program blocked on the second pthread_spin_lock, never return:

$ ./double_lock

P.S., the code can be found here.