1  /* Test concurrent dlopen and pthread_create: BZ 19329.
       2     Copyright (C) 2021-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <http://www.gnu.org/licenses/>.  */
      18  
      19  #include <dlfcn.h>
      20  #include <pthread.h>
      21  #include <stdio.h>
      22  #include <stdatomic.h>
      23  #include <support/xdlfcn.h>
      24  #include <support/xthread.h>
      25  
      26  #define THREADS 10000
      27  
      28  static atomic_int done;
      29  
      30  static void *
      31  start (void *a)
      32  {
      33    /* Load a module with many dependencies that each have TLS.  */
      34    xdlopen ("tst-tls21mod.so", RTLD_LAZY);
      35    atomic_store_explicit (&done, 1, memory_order_release);
      36    return 0;
      37  }
      38  
      39  static void *
      40  nop (void *a)
      41  {
      42    return 0;
      43  }
      44  
      45  static int
      46  do_test (void)
      47  {
      48    pthread_t t1, t2;
      49    int i;
      50  
      51    /* Load a module with lots of dependencies and TLS.  */
      52    t1 = xpthread_create (0, start, 0);
      53  
      54    /* Concurrently create lots of threads until dlopen is observably done.  */
      55    for (i = 0; i < THREADS; i++)
      56      {
      57        if (atomic_load_explicit (&done, memory_order_acquire) != 0)
      58  	break;
      59        t2 = xpthread_create (0, nop, 0);
      60        xpthread_join (t2);
      61      }
      62  
      63    xpthread_join (t1);
      64    printf ("threads created during dlopen: %d\n", i);
      65    return 0;
      66  }
      67  
      68  #include <support/test-driver.c>