/* Testing race while enabling lock elision.

   Copyright (C) 2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <stdio.h>

#include <stdlib.h>

#include <stdint.h>

#include <pthread.h>

#include <unistd.h>

#include <getopt.h>

#include <support/support.h>

#include <support/xthread.h>

static pthread_barrier_t barrier;

static pthread_mutex_t mutex;

static long long int iteration_count = 1000000;

static unsigned int thread_count = 3;

static void *

thr_func (void *arg)

{

  long long int i;

  for (i = 0; i < iteration_count; i++)

    {

      if ((uintptr_t) arg == 0)

	{

	  xpthread_mutex_destroy (&mutex);

	  xpthread_mutex_init (&mutex, NULL);

	}

      xpthread_barrier_wait (&barrier);

      /* Test if enabling lock elision works if it is enabled concurrently.

	 There was a race in FORCE_ELISION macro which leads to either

	 pthread_mutex_destroy returning EBUSY as the owner was recorded

	 by pthread_mutex_lock - in "normal mutex" code path - but was not

	 resetted in pthread_mutex_unlock - in "elision" code path.

	 Or it leads to the assertion in nptl/pthread_mutex_lock.c:

	 assert (mutex->__data.__owner == 0);

	 Please ensure that the test is run with lock elision:

	 export GLIBC_TUNABLES=glibc.elision.enable=1  */

      xpthread_mutex_lock (&mutex);

      xpthread_mutex_unlock (&mutex);

      xpthread_barrier_wait (&barrier);

    }

  return NULL;

}

static int

do_test (void)

{

  unsigned int i;

  printf ("Starting %d threads to run %lld iterations.\n",

	  thread_count, iteration_count);

  pthread_t *threads = xmalloc (thread_count * sizeof (pthread_t));

  xpthread_barrier_init (&barrier, NULL, thread_count);

  xpthread_mutex_init (&mutex, NULL);

  for (i = 0; i < thread_count; i++)

    threads[i] = xpthread_create (NULL, thr_func, (void *) (uintptr_t) i);

  for (i = 0; i < thread_count; i++)

    xpthread_join (threads[i]);

  xpthread_barrier_destroy (&barrier);

  free (threads);

  return EXIT_SUCCESS;

}

#define OPT_ITERATIONS	10000

#define OPT_THREADS	10001

#define CMDLINE_OPTIONS						\

  { "iterations", required_argument, NULL, OPT_ITERATIONS },	\

  { "threads", required_argument, NULL, OPT_THREADS },

static void

cmdline_process (int c)

{

  long long int arg = strtoll (optarg, NULL, 0);

  switch (c)

    {

    case OPT_ITERATIONS:

      if (arg > 0)

	iteration_count = arg;

      break;

    case OPT_THREADS:

      if (arg > 0 && arg < 100)

	thread_count = arg;

      break;

    }

}

#define CMDLINE_PROCESS cmdline_process

#define TIMEOUT 50

#include <support/test-driver.c>