Implementing worker threads (in Linux): How offensive is this?

Question

#include <pthread.h>
static void * worker_thread(void *);

void some_func(void)
{
    pthread_t * tmp;
    tmp = malloc(sizeof(pthread_t));
    if (NULL != tmp)
    {
        if (!pthread_create(tmp, NULL, worker_thread, (void *)tmp))
            pthread_detach(*tmp);
        else
            free(tmp);
    }
}

static void * worker_thread(void * p)
{
    /* do work */
    free(p);
    return(NULL);
}

Answer 1

What I learned from the comments is that the pthread_t structure isn't required to be 'alive' for the duration of thread (which is what I thought and why I used malloc); a stack variable is fine. What I ended up doing was based on Jason Coco's comment:

#include <pthread.h>

static void * worker_thread(void *);

void start_worker(void * arg)
{
    pthread_t tmp;
    (void)pthread_create(& tmp, NULL, worker_thread, arg))
}

static void * worker_thread(void * p)
{
    /* do work */

    /* finished work */
    pthread_detach(pthread_self());
    return (p);
}