pthread.c

#include <dlfcn.h>
#include <stdio.h>
#include <pthread.h>
#include <time.h>
#include <stdlib.h>

int (*original_pthread_create)(pthread_t *thread, const pthread_attr_t *attr, void *(*start_routine) (void *), void *arg) = NULL;

void load_original_pthread_create() {
    void *handle = dlopen("libpthread-2.27.so", RTLD_LAZY);
    char *err = dlerror();
    if (err) {
        printf("%s\n", err);
    }
    original_pthread_create = dlsym(handle, "pthread_create");
    err = dlerror();
    if (err) {
        printf("%s\n", err);
    }
}
int pthread_create(pthread_t *thread, const pthread_attr_t *attr, void *(*start_routine) (void *), void *arg) {
    if (original_pthread_create == NULL) {
        load_original_pthread_create();
    }
    static int count = 0;
    if(count == 0) {
        srand(time(NULL));
        count++;
    }
    struct sched_param rr_param;

    pthread_attr_t custom_sched_attr;
    if(!attr)
    	pthread_attr_init(&custom_sched_attr);
    else
        custom_sched_attr = *attr;
    pthread_attr_setscope(&custom_sched_attr, PTHREAD_SCOPE_PROCESS);
    pthread_attr_setinheritsched(&custom_sched_attr, PTHREAD_EXPLICIT_SCHED);
    pthread_attr_setschedpolicy(&custom_sched_attr, SCHED_RR);
    int rr_max_prio = sched_get_priority_max(SCHED_RR);
    int rr_min_prio = sched_get_priority_min(SCHED_RR);
    int prio = rand()%(rr_max_prio - rr_min_prio + 1) + rr_min_prio;
    rr_param.sched_priority = prio;
    pthread_attr_setschedparam(&custom_sched_attr, &rr_param);

    int ret = original_pthread_create(thread, &custom_sched_attr, start_routine, arg);
    printf("%lu %d\n", *thread, prio);

    return ret;
}

A wrapper to pthread_create function call which randomly assigns a priority to a thread. This can be used to detect concurrency bugs. Change pthread library version in line 11 to the one the application binary uses.

Compile

gcc pthread.c -o libmypthread.so -shared -fpic -ldl

Run

sudo LD_PRELOAD=./libmypthread.so ./<application_binary_you_want_to_test>