Strange deadlock problem with glibc 2.1.91

[Craig Rodrigues <rodrigc at mediaone dot net>]

Hi,

I am trying to track down why Realplayer7 does not seem to
work with glibc 2.1.91 obtained from rawhide.redhat.com.

I started running gdb against Realplayer, and saw that
it seemed to be hanging in places with a backtrace like:
#0  0x4004fa98 in __sigsuspend (set=0xbfffeff0)
    at ../sysdeps/unix/sysv/linux/sigsuspend.c:53
#1  0x4029f953 in __pthread_wait_for_restart_signal (self=0x402a8ce0)
    at pthread.c:806
#2  0x4029c298 in pthread_join (thread_id=1026, thread_return=0xbffff1a4)
    at restart.h:36

I suspected it might be a thread deadlocking problem, so I wrote
a small test program test_thread.cpp.  If I uncomment the line in
my test program:
cout << "Hello in cout" << endl;

then this test program consistently deadlocks, but if I take it out, it is
fine.

On a Linux system with glibc 2.1, I saw no problems with the same program.

Does anybody have any idea what could be wrong?

Thanks.

-- 
Craig Rodrigues        
http://www.gis.net/~craigr    
rodrigc@mediaone.net          
#include <stdio.h>


#include <pthread.h>
#include <sched.h>
#include <iostream>


void *Test(void *);      // Must be void *, defined in pthread.h !

int COUNT = 0;

/**********************************************************************/

int main (int argc, char **argv)

{ pthread_t tid[4];;
 int i,ret;

 // Create some threads

 ret = pthread_create(&(tid[0]), NULL, Test, (void *)"");
 ret = pthread_create(&(tid[1]), NULL, Test, (void *)"");
 ret = pthread_create(&(tid[2]), NULL, Test, (void *)"");
 ret = pthread_create(&(tid[3]), NULL, Test, (void *)"");

 printf( "Parent thread waiting...\n");

 // If we don't wait for the threads, they will be killed
 // before they can start...

 for (i = 0; i < 4; i++)
   {
     ret = pthread_join(tid[i],(void **)NULL);
   }

 printf( "Parent thread continuing\n");
 printf("COUNT = %d\n", COUNT);
}

/**********************************************************************/

void *Test(void *fname)

{ 
  pthread_mutex_t mutex;
  int ret;

  int i=0;
  while ( i++ != 500)
    {
   
      ret = pthread_mutex_lock(&mutex);
      COUNT++;
      ret = pthread_mutex_unlock(&mutex);
      printf("%d\n", COUNT);   
      printf("Hello in printf");
   
      // Uncomment the next line to see a deadlock 
      //cout << "Hello in cout" << endl;
    }

}