foo.c

#include <CoreFoundation/CoreFoundation.h>
#include <pthread.h>

void* foo(void *foo) {
    return NULL;
}

int main(int argc, char **argv) {
    pthread_t thread;
    pthread_create(&thread, NULL, &foo, NULL);
    void *t;
    pthread_join(thread, &t);
    execvp("ls", (char *[]){"ls", ".", NULL});
    perror("ls");
    return -1;
}

Cydia Substrate bug, fixed on 0.9.7108 or higher.