Debian pthread_join bus error

Question

I am sitting on a Beaglebone Black and having problem with pthread_join, which gives me Bus error. See the following code below. This is taken directly from a Youtube-tutorial on pthreads.

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

void *myfunc (void *myvar);

int main(int argc, char* argv[])
{
    pthread_t thread1, thread2;
    char *msg1 = "First thread";
    char *msg2 = "Second thread";
    int ret1, ret2;

    ret1 = pthread_create(&thread1, NULL, myfunc, (void *) msg1);
    ret2 = pthread_create(&thread1, NULL, myfunc, (void *) msg2);

    printf("Main function after pthread_create\n");

    pthread_join(thread1, NULL);
    pthread_join(thread2, NULL);

    // Bus error on the above pthread_join
    printf("Here is OK\n"); 
    printf("First thread ret1 = %d\n", ret1);
    printf("Second thread ret2 = %d\n", ret2);

   return 0;
}

void *myfunc (void *myvar)
{
   char *msg;
   msg = (char *) myvar;

   int i;
   for(i=0; i < 10; i++)
   {
       printf("%s %d\n", msg, i);
       sleep(1);
   }

 return NULL;

}

This code works perfectly on my PC running Ubuntu 14.04, although Valgrind shows some "possibly lost" bytes on the pthread_join command. Hence the code is not the problem - I figure it must be something on the Debian running on Beaglebone that's causing it. And yes, I do include the -lpthread library.

The output I get on the Beaglebone is:

Main function after pthread_create
Second thread 0
First thread 0
Second thread 1
First thread 1
Second thread 2
First thread 2
Second thread 3
First thread 3
Second thread 4
First thread 4
Second thread 5
First thread 5
Second thread 6
First thread 6
Second thread 7
First thread 7
Second thread 8
First thread 8
Second thread 9
First thread 9
Bus error

The Debian-version running on Beaglebone:

Distributor ID: Debian
Description:    Debian GNU/Linux 7.8 (wheezy)
Release:        7.8
Codename:       wheezy

EDIT: the following debug info is printed:

Program received signal SIGBUS, Bus error.
0xb6fbdbd0 in pthread_join () from /lib/arm-linux-gnueabih/libpthread.so.0

Thanks for all the tips in advance.

Answer 1

There's a mistake (typo? error in the original?) here:

ret1 = pthread_create(&thread1, NULL, myfunc, (void *) msg1);
ret2 = pthread_create(&thread1, NULL, myfunc, (void *) msg2);

You store both thread IDs in thread1, leaving thread2 uninitialized. The second call to pthread_create() should use &thread2.