commit 71e6e5e52d7205a6a792bf9b754550a8719db6b1
Author: Asim YarKhan <yarkhan@icl.utk.edu>
Date:   Wed Feb 25 12:17:40 2015 -0500

    Sync thread exit in krental_threads.c
    
    Thanks to William Cohen for this patch and to Phil Mucci for approving it.
    
    William Cohnen and Michael Petlan noticed that this test can have
    threads dangling after the main thread is done.  This patch tracks the
    created threads and ensures that they are joined before the code
    exits.
    
    Note: There is still some problem remaining. For example, the following
    test will sometimes (maybe 1 of 10 runs) generate an error message.
    > ./ctests/krentel_pthreads 8 2000 10
    ....
    [10] time = 8, count = 38110, iter = 20, rate = 1905500.0/Kiter
    PAPI Error: thread->running_eventset == NULL in _papi_pe_dispatch_timer for fd 14!.
    [0] time = 8, count = 38161, iter = 20, rate = 1908050.0/Kiter
    krentel_pthreads.c               PASSED

diff --git a/src/ctests/krentel_pthreads.c b/src/ctests/krentel_pthreads.c
index 2417976..9fa3e25 100644
--- a/src/ctests/krentel_pthreads.c
+++ b/src/ctests/krentel_pthreads.c
@@ -143,7 +143,7 @@ my_thread( void *v )
 int
 main( int argc, char **argv )
 {
-	pthread_t td;
+	pthread_t *td = NULL;
 	long n;
 
 	tests_quiet( argc, argv );	/*Set TESTS_QUIET variable */
@@ -155,6 +155,10 @@ main( int argc, char **argv )
 	if ( argc < 4 || sscanf( argv[3], "%d", &num_threads ) < 1 )
 		num_threads = 3;
 
+	td = malloc((num_threads+1) * sizeof(pthread_t));
+	if (!td)
+		test_fail( __FILE__, __LINE__, "td malloc failed", 1 );
+
 	printf( "program_time = %d, threshold = %d, num_threads = %d\n\n",
 			program_time, threshold, num_threads );
 
@@ -171,15 +175,22 @@ main( int argc, char **argv )
 	gettimeofday( &start, NULL );
 
 	for ( n = 1; n <= num_threads; n++ ) {
-		if ( pthread_create( &td, NULL, my_thread, ( void * ) n ) != 0 )
+		if ( pthread_create( &(td[n]), NULL, my_thread, ( void * ) n ) != 0 )
 			test_fail( __FILE__, __LINE__, "pthread create failed", 1 );
 	}
 
 	my_thread( ( void * ) 0 );
 
+	/* wait for all the threads */
+	for ( n = 1; n <= num_threads; n++ ) {
+	  	if ( pthread_join( td[n], NULL))
+			test_fail( __FILE__, __LINE__, "pthread join failed", 1 );
+	}
+
+	free(td);
+
 	printf( "done\n" );
 
 	test_pass( __FILE__, NULL, 0 );
-	pthread_exit( NULL );
 	return ( 0 );
 }