pthread_mutex_timedlock problem

["Robert Strycek" <strycek@posam.sk>]

Hello All,
I'm working on an rw-mutex and found something like a dead lock when 
testing timed lock functions.
To be sure, I wrote a simple test program, which hangs up, too.
after ~4 loops it's dead (on 1GHz P3, Win2k)
Here it is:

#include <windows.h>
#include <sys/timeb.h>
#include "lib/pthreads/pthread.h"
#define DELAY                   200
#define _log(what)              OutputDebugString( what )

pthread_mutex_t mut;

void * thread_proc_w( void * );

int APIENTRY WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR 
lpCmdLine, int nCmdShow )
{
        int i;
        pthread_t th_w[2];
        pthread_mutexattr_t m;
        pthread_mutexattr_init( &m );
        pthread_mutexattr_settype( &m, PTHREAD_MUTEX_NORMAL ); 
//PTHREAD_MUTEX_RECURSIVE
        pthread_mutex_init( &mut, &m );
        pthread_mutexattr_destroy( &m );
        for( i=0; i<2; i++ )
                pthread_create( &th_w[i], NULL, thread_proc_w, (void *) i 
);
        while( 1 )
                Sleep( 1000 );
        return 0;
}

void * thread_proc_w( void * param )
{
        timespec ts;
        _timeb tb;
        while( 1 ) {
                Sleep( 100 );
                while( 1 ) {
                        _ftime( &tb );
                        ts.tv_sec = DELAY/1000 + tb.time;
                        ts.tv_nsec = (DELAY%1000 + tb.millitm) * 1000000;

                        int ret = pthread_mutex_timedlock( &mut, &ts );  
// this makes problems
                        if( ret == 0 )
                                break;
                }
                _log( param ? "\r\nL0" : "\r\nL1" );    //I'm alive
                Sleep( 500 );
                _log( param ? "u0" : "u1" );            //unlocking ...
                pthread_mutex_unlock( &mut );
        }
        pthread_exit( 0 );
        return 0;
}

-------------------------------

(values in Sleep() do matter - some values work fine)
After a few loops, the mutex 'mut' cannot be locked no more.
Does anyone have any idea what's wrong ?

Thanks,

Robo