系统+ usleep +多线程= SEGV / SIGILL

Question

I am using kernel version 2.6.10 and "plain" C.

I have narrowed-down to two threads on why our program crashes.

TIMER THREAD

void TimerThread(void)
{
    while (exec) {
        usleep(10000);

        RSLTCD r = SUCCESS;
        // r = LockMutex(Mtx);
        do {
              // some process
        } while(1);     
        // r = UnlockMutex(Mtx);
    }
    return ;        // Not Reached
}

SYSTEM THREAD

void SystemThread(void)
{
    CreateThread(TimerThread, OALTHRD_DEFAULT_STACKSIZE, THREADPRI_NORMAL, 0, 0);
    for(;;){
        system("echo this is a SYSTEM CALL 1");
        system("echo this is a SYSTEM CALL 2");
    }    
}

I have remove all the rest of the code and even with just running this two "simple" threads, the program will crash after a few loops(50-100). I have also read that system() uses fork() and there are sometimes trouble with fork()ing and mutexes. So I removed the mutex part and still it crashes.

I tried making my own "system call" function using fork()+execv() combo and also posix_spawn(). Both cases resulted with the same result.

Also, I have tried using other sleep functions than usleep.(nano_sleep, etc) Still the programs crashes

Is there trouble with using system() and usleep() in multi-thread processes? What other alternatives do I have other than using these functions?

Answer 1

Basically it is not easy to mix multi-threading and "fork()" and a lot more details about your SW would be needed to provide useful help. Please read http://www.linuxprogrammingblog.com/threads-and-fork-think-twice-before-using-them for description of the problems when mixing threads and fork().