nptl/pthread_create.c

   1 /* Copyright (C) 2002-2014 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   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 <ctype.h>
  20 #include <errno.h>
  21 #include <stdbool.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <stdint.h>
  25 #include "pthreadP.h"
  26 #include <hp-timing.h>
  27 #include <ldsodefs.h>
  28 #include <atomic.h>
  29 #include <libc-internal.h>
  30 #include <resolv.h>
  31 #include <kernel-features.h>
  32 #include <exit-thread.h>
  33
  34 #include <shlib-compat.h>
  35
  36 #include <stap-probe.h>
  37
  38
  39 /* Local function to start thread and handle cleanup.  */
  40 static int start_thread (void *arg);
  41
  42
  43 /* Nozero if debugging mode is enabled.  */
  44 int __pthread_debug;
  45
  46 /* Globally enabled events.  */
  47 static td_thr_events_t __nptl_threads_events __attribute_used__;
  48
  49 /* Pointer to descriptor with the last event.  */
  50 static struct pthread *__nptl_last_event __attribute_used__;
  51
  52 /* Number of threads running.  */
  53 unsigned int __nptl_nthreads = 1;
  54
  55
  56 /* Code to allocate and deallocate a stack.  */
  57 #include "allocatestack.c"
  58
  59 /* Code to create the thread.  */
  60 #include <createthread.c>
  61
  62
  63 struct pthread *
  64 internal_function
  65 __find_in_stack_list (pd)
  66      struct pthread *pd;
  67 {
  68   list_t *entry;
  69   struct pthread *result = NULL;
  70
  71   lll_lock (stack_cache_lock, LLL_PRIVATE);
  72
  73   list_for_each (entry, &stack_used)
  74     {
  75       struct pthread *curp;
  76
  77       curp = list_entry (entry, struct pthread, list);
  78       if (curp == pd)
  79         {
  80           result = curp;
  81           break;
  82         }
  83     }
  84
  85   if (result == NULL)
  86     list_for_each (entry, &__stack_user)
  87       {
  88         struct pthread *curp;
  89
  90         curp = list_entry (entry, struct pthread, list);
  91         if (curp == pd)
  92           {
  93             result = curp;
  94             break;
  95           }
  96       }
  97
  98   lll_unlock (stack_cache_lock, LLL_PRIVATE);
  99
 100   return result;
 101 }
 102
 103
 104 /* Deallocate POSIX thread-local-storage.  */
 105 void
 106 attribute_hidden
 107 __nptl_deallocate_tsd (void)
 108 {
 109   struct pthread *self = THREAD_SELF;
 110
 111   /* Maybe no data was ever allocated.  This happens often so we have
 112      a flag for this.  */
 113   if (THREAD_GETMEM (self, specific_used))
 114     {
 115       size_t round;
 116       size_t cnt;
 117
 118       round = 0;
 119       do
 120         {
 121           size_t idx;
 122
 123           /* So far no new nonzero data entry.  */
 124           THREAD_SETMEM (self, specific_used, false);
 125
 126           for (cnt = idx = 0; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt)
 127             {
 128               struct pthread_key_data *level2;
 129
 130               level2 = THREAD_GETMEM_NC (self, specific, cnt);
 131
 132               if (level2 != NULL)
 133                 {
 134                   size_t inner;
 135
 136                   for (inner = 0; inner < PTHREAD_KEY_2NDLEVEL_SIZE;
 137                        ++inner, ++idx)
 138                     {
 139                       void *data = level2[inner].data;
 140
 141                       if (data != NULL)
 142                         {
 143                           /* Always clear the data.  */
 144                           level2[inner].data = NULL;
 145
 146                           /* Make sure the data corresponds to a valid
 147                              key.  This test fails if the key was
 148                              deallocated and also if it was
 149                              re-allocated.  It is the user's
 150                              responsibility to free the memory in this
 151                              case.  */
 152                           if (level2[inner].seq
 153                               == __pthread_keys[idx].seq
 154                               /* It is not necessary to register a destructor
 155                                  function.  */
 156                               && __pthread_keys[idx].destr != NULL)
 157                             /* Call the user-provided destructor.  */
 158                             __pthread_keys[idx].destr (data);
 159                         }
 160                     }
 161                 }
 162               else
 163                 idx += PTHREAD_KEY_1STLEVEL_SIZE;
 164             }
 165
 166           if (THREAD_GETMEM (self, specific_used) == 0)
 167             /* No data has been modified.  */
 168             goto just_free;
 169         }
 170       /* We only repeat the process a fixed number of times.  */
 171       while (__builtin_expect (++round < PTHREAD_DESTRUCTOR_ITERATIONS, 0));
 172
 173       /* Just clear the memory of the first block for reuse.  */
 174       memset (&THREAD_SELF->specific_1stblock, '\0',
 175               sizeof (self->specific_1stblock));
 176
 177     just_free:
 178       /* Free the memory for the other blocks.  */
 179       for (cnt = 1; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt)
 180         {
 181           struct pthread_key_data *level2;
 182
 183           level2 = THREAD_GETMEM_NC (self, specific, cnt);
 184           if (level2 != NULL)
 185             {
 186               /* The first block is allocated as part of the thread
 187                  descriptor.  */
 188               free (level2);
 189               THREAD_SETMEM_NC (self, specific, cnt, NULL);
 190             }
 191         }
 192
 193       THREAD_SETMEM (self, specific_used, false);
 194     }
 195 }
 196
 197
 198 /* Deallocate a thread's stack after optionally making sure the thread
 199    descriptor is still valid.  */
 200 void
 201 internal_function
 202 __free_tcb (struct pthread *pd)
 203 {
 204   /* The thread is exiting now.  */
 205   if (__builtin_expect (atomic_bit_test_set (&pd->cancelhandling,
 206                                              TERMINATED_BIT) == 0, 1))
 207     {
 208       /* Remove the descriptor from the list.  */
 209       if (DEBUGGING_P && __find_in_stack_list (pd) == NULL)
 210         /* Something is really wrong.  The descriptor for a still
 211            running thread is gone.  */
 212         abort ();
 213
 214       /* Free TPP data.  */
 215       if (__glibc_unlikely (pd->tpp != NULL))
 216         {
 217           struct priority_protection_data *tpp = pd->tpp;
 218
 219           pd->tpp = NULL;
 220           free (tpp);
 221         }
 222
 223       /* Queue the stack memory block for reuse and exit the process.  The
 224          kernel will signal via writing to the address returned by
 225          QUEUE-STACK when the stack is available.  */
 226       __deallocate_stack (pd);
 227     }
 228 }
 229
 230
 231 static int
 232 start_thread (void *arg)
 233 {
 234   struct pthread *pd = (struct pthread *) arg;
 235
 236 #if HP_TIMING_AVAIL
 237   /* Remember the time when the thread was started.  */
 238   hp_timing_t now;
 239   HP_TIMING_NOW (now);
 240   THREAD_SETMEM (pd, cpuclock_offset, now);
 241 #endif
 242
 243   /* Initialize resolver state pointer.  */
 244   __resp = &pd->res;
 245
 246   /* Initialize pointers to locale data.  */
 247   __ctype_init ();
 248
 249   /* Allow setxid from now onwards.  */
 250   if (__glibc_unlikely (atomic_exchange_acq (&pd->setxid_futex, 0) == -2))
 251     lll_futex_wake (&pd->setxid_futex, 1, LLL_PRIVATE);
 252
 253 #ifdef __NR_set_robust_list
 254 # ifndef __ASSUME_SET_ROBUST_LIST
 255   if (__set_robust_list_avail >= 0)
 256 # endif
 257     {
 258       INTERNAL_SYSCALL_DECL (err);
 259       /* This call should never fail because the initial call in init.c
 260          succeeded.  */
 261       INTERNAL_SYSCALL (set_robust_list, err, 2, &pd->robust_head,
 262                         sizeof (struct robust_list_head));
 263     }
 264 #endif
 265
 266   /* If the parent was running cancellation handlers while creating
 267      the thread the new thread inherited the signal mask.  Reset the
 268      cancellation signal mask.  */
 269   if (__glibc_unlikely (pd->parent_cancelhandling & CANCELING_BITMASK))
 270     {
 271       INTERNAL_SYSCALL_DECL (err);
 272       sigset_t mask;
 273       __sigemptyset (&mask);
 274       __sigaddset (&mask, SIGCANCEL);
 275       (void) INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_UNBLOCK, &mask,
 276                                NULL, _NSIG / 8);
 277     }
 278
 279   /* This is where the try/finally block should be created.  For
 280      compilers without that support we do use setjmp.  */
 281   struct pthread_unwind_buf unwind_buf;
 282
 283   /* No previous handlers.  */
 284   unwind_buf.priv.data.prev = NULL;
 285   unwind_buf.priv.data.cleanup = NULL;
 286
 287   int not_first_call;
 288   not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
 289   if (__glibc_likely (! not_first_call))
 290     {
 291       /* Store the new cleanup handler info.  */
 292       THREAD_SETMEM (pd, cleanup_jmp_buf, &unwind_buf);
 293
 294       if (__glibc_unlikely (pd->stopped_start))
 295         {
 296           int oldtype = CANCEL_ASYNC ();
 297
 298           /* Get the lock the parent locked to force synchronization.  */
 299           lll_lock (pd->lock, LLL_PRIVATE);
 300           /* And give it up right away.  */
 301           lll_unlock (pd->lock, LLL_PRIVATE);
 302
 303           CANCEL_RESET (oldtype);
 304         }
 305
 306       LIBC_PROBE (pthread_start, 3, (pthread_t) pd, pd->start_routine, pd->arg);
 307
 308       /* Run the code the user provided.  */
 309 #ifdef CALL_THREAD_FCT
 310       THREAD_SETMEM (pd, result, CALL_THREAD_FCT (pd));
 311 #else
 312       THREAD_SETMEM (pd, result, pd->start_routine (pd->arg));
 313 #endif
 314     }
 315
 316   /* Call destructors for the thread_local TLS variables.  */
 317 #ifndef SHARED
 318   if (&__call_tls_dtors != NULL)
 319 #endif
 320     __call_tls_dtors ();
 321
 322   /* Run the destructor for the thread-local data.  */
 323   __nptl_deallocate_tsd ();
 324
 325   /* Clean up any state libc stored in thread-local variables.  */
 326   __libc_thread_freeres ();
 327
 328   /* If this is the last thread we terminate the process now.  We
 329      do not notify the debugger, it might just irritate it if there
 330      is no thread left.  */
 331   if (__glibc_unlikely (atomic_decrement_and_test (&__nptl_nthreads)))
 332     /* This was the last thread.  */
 333     exit (0);
 334
 335   /* Report the death of the thread if this is wanted.  */
 336   if (__glibc_unlikely (pd->report_events))
 337     {
 338       /* See whether TD_DEATH is in any of the mask.  */
 339       const int idx = __td_eventword (TD_DEATH);
 340       const uint32_t mask = __td_eventmask (TD_DEATH);
 341
 342       if ((mask & (__nptl_threads_events.event_bits[idx]
 343                    | pd->eventbuf.eventmask.event_bits[idx])) != 0)
 344         {
 345           /* Yep, we have to signal the death.  Add the descriptor to
 346              the list but only if it is not already on it.  */
 347           if (pd->nextevent == NULL)
 348             {
 349               pd->eventbuf.eventnum = TD_DEATH;
 350               pd->eventbuf.eventdata = pd;
 351
 352               do
 353                 pd->nextevent = __nptl_last_event;
 354               while (atomic_compare_and_exchange_bool_acq (&__nptl_last_event,
 355                                                            pd, pd->nextevent));
 356             }
 357
 358           /* Now call the function to signal the event.  */
 359           __nptl_death_event ();
 360         }
 361     }
 362
 363   /* The thread is exiting now.  Don't set this bit until after we've hit
 364      the event-reporting breakpoint, so that td_thr_get_info on us while at
 365      the breakpoint reports TD_THR_RUN state rather than TD_THR_ZOMBIE.  */
 366   atomic_bit_set (&pd->cancelhandling, EXITING_BIT);
 367
 368 #ifndef __ASSUME_SET_ROBUST_LIST
 369   /* If this thread has any robust mutexes locked, handle them now.  */
 370 # ifdef __PTHREAD_MUTEX_HAVE_PREV
 371   void *robust = pd->robust_head.list;
 372 # else
 373   __pthread_slist_t *robust = pd->robust_list.__next;
 374 # endif
 375   /* We let the kernel do the notification if it is able to do so.
 376      If we have to do it here there for sure are no PI mutexes involved
 377      since the kernel support for them is even more recent.  */
 378   if (__set_robust_list_avail < 0
 379       && __builtin_expect (robust != (void *) &pd->robust_head, 0))
 380     {
 381       do
 382         {
 383           struct __pthread_mutex_s *this = (struct __pthread_mutex_s *)
 384             ((char *) robust - offsetof (struct __pthread_mutex_s,
 385                                          __list.__next));
 386           robust = *((void **) robust);
 387
 388 # ifdef __PTHREAD_MUTEX_HAVE_PREV
 389           this->__list.__prev = NULL;
 390 # endif
 391           this->__list.__next = NULL;
 392
 393           lll_robust_dead (this->__lock, /* XYZ */ LLL_SHARED);
 394         }
 395       while (robust != (void *) &pd->robust_head);
 396     }
 397 #endif
 398
 399   /* Mark the memory of the stack as usable to the kernel.  We free
 400      everything except for the space used for the TCB itself.  */
 401   size_t pagesize_m1 = __getpagesize () - 1;
 402 #ifdef _STACK_GROWS_DOWN
 403   char *sp = CURRENT_STACK_FRAME;
 404   size_t freesize = (sp - (char *) pd->stackblock) & ~pagesize_m1;
 405 #else
 406 # error "to do"
 407 #endif
 408   assert (freesize < pd->stackblock_size);
 409   if (freesize > PTHREAD_STACK_MIN)
 410     __madvise (pd->stackblock, freesize - PTHREAD_STACK_MIN, MADV_DONTNEED);
 411
 412   /* If the thread is detached free the TCB.  */
 413   if (IS_DETACHED (pd))
 414     /* Free the TCB.  */
 415     __free_tcb (pd);
 416   else if (__glibc_unlikely (pd->cancelhandling & SETXID_BITMASK))
 417     {
 418       /* Some other thread might call any of the setXid functions and expect
 419          us to reply.  In this case wait until we did that.  */
 420       do
 421         lll_futex_wait (&pd->setxid_futex, 0, LLL_PRIVATE);
 422       while (pd->cancelhandling & SETXID_BITMASK);
 423
 424       /* Reset the value so that the stack can be reused.  */
 425       pd->setxid_futex = 0;
 426     }
 427
 428   /* We cannot call '_exit' here.  '_exit' will terminate the process.
 429
 430      The 'exit' implementation in the kernel will signal when the
 431      process is really dead since 'clone' got passed the CLONE_CHILD_CLEARTID
 432      flag.  The 'tid' field in the TCB will be set to zero.
 433
 434      The exit code is zero since in case all threads exit by calling
 435      'pthread_exit' the exit status must be 0 (zero).  */
 436   __exit_thread ();
 437
 438   /* NOTREACHED */
 439   return 0;
 440 }
 441
 442
 443 int
 444 __pthread_create_2_1 (newthread, attr, start_routine, arg)
 445      pthread_t *newthread;
 446      const pthread_attr_t *attr;
 447      void *(*start_routine) (void *);
 448      void *arg;
 449 {
 450   STACK_VARIABLES;
 451
 452   const struct pthread_attr *iattr = (struct pthread_attr *) attr;
 453   struct pthread_attr default_attr;
 454   bool free_cpuset = false;
 455   if (iattr == NULL)
 456     {
 457       lll_lock (__default_pthread_attr_lock, LLL_PRIVATE);
 458       default_attr = __default_pthread_attr;
 459       size_t cpusetsize = default_attr.cpusetsize;
 460       if (cpusetsize > 0)
 461         {
 462           cpu_set_t *cpuset;
 463           if (__glibc_likely (__libc_use_alloca (cpusetsize)))
 464             cpuset = __alloca (cpusetsize);
 465           else
 466             {
 467               cpuset = malloc (cpusetsize);
 468               if (cpuset == NULL)
 469                 {
 470                   lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE);
 471                   return ENOMEM;
 472                 }
 473               free_cpuset = true;
 474             }
 475           memcpy (cpuset, default_attr.cpuset, cpusetsize);
 476           default_attr.cpuset = cpuset;
 477         }
 478       lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE);
 479       iattr = &default_attr;
 480     }
 481
 482   struct pthread *pd = NULL;
 483   int err = ALLOCATE_STACK (iattr, &pd);
 484   int retval = 0;
 485
 486   if (__glibc_unlikely (err != 0))
 487     /* Something went wrong.  Maybe a parameter of the attributes is
 488        invalid or we could not allocate memory.  Note we have to
 489        translate error codes.  */
 490     {
 491       retval = err == ENOMEM ? EAGAIN : err;
 492       goto out;
 493     }
 494
 495
 496   /* Initialize the TCB.  All initializations with zero should be
 497      performed in 'get_cached_stack'.  This way we avoid doing this if
 498      the stack freshly allocated with 'mmap'.  */
 499
 500 #if TLS_TCB_AT_TP
 501   /* Reference to the TCB itself.  */
 502   pd->header.self = pd;
 503
 504   /* Self-reference for TLS.  */
 505   pd->header.tcb = pd;
 506 #endif
 507
 508   /* Store the address of the start routine and the parameter.  Since
 509      we do not start the function directly the stillborn thread will
 510      get the information from its thread descriptor.  */
 511   pd->start_routine = start_routine;
 512   pd->arg = arg;
 513
 514   /* Copy the thread attribute flags.  */
 515   struct pthread *self = THREAD_SELF;
 516   pd->flags = ((iattr->flags & ~(ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET))
 517                | (self->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)));
 518
 519   /* Initialize the field for the ID of the thread which is waiting
 520      for us.  This is a self-reference in case the thread is created
 521      detached.  */
 522   pd->joinid = iattr->flags & ATTR_FLAG_DETACHSTATE ? pd : NULL;
 523
 524   /* The debug events are inherited from the parent.  */
 525   pd->eventbuf = self->eventbuf;
 526
 527
 528   /* Copy the parent's scheduling parameters.  The flags will say what
 529      is valid and what is not.  */
 530   pd->schedpolicy = self->schedpolicy;
 531   pd->schedparam = self->schedparam;
 532
 533   /* Copy the stack guard canary.  */
 534 #ifdef THREAD_COPY_STACK_GUARD
 535   THREAD_COPY_STACK_GUARD (pd);
 536 #endif
 537
 538   /* Copy the pointer guard value.  */
 539 #ifdef THREAD_COPY_POINTER_GUARD
 540   THREAD_COPY_POINTER_GUARD (pd);
 541 #endif
 542
 543   /* Determine scheduling parameters for the thread.  */
 544   if (__builtin_expect ((iattr->flags & ATTR_FLAG_NOTINHERITSCHED) != 0, 0)
 545       && (iattr->flags & (ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET)) != 0)
 546     {
 547       INTERNAL_SYSCALL_DECL (scerr);
 548
 549       /* Use the scheduling parameters the user provided.  */
 550       if (iattr->flags & ATTR_FLAG_POLICY_SET)
 551         pd->schedpolicy = iattr->schedpolicy;
 552       else if ((pd->flags & ATTR_FLAG_POLICY_SET) == 0)
 553         {
 554           pd->schedpolicy = INTERNAL_SYSCALL (sched_getscheduler, scerr, 1, 0);
 555           pd->flags |= ATTR_FLAG_POLICY_SET;
 556         }
 557
 558       if (iattr->flags & ATTR_FLAG_SCHED_SET)
 559         memcpy (&pd->schedparam, &iattr->schedparam,
 560                 sizeof (struct sched_param));
 561       else if ((pd->flags & ATTR_FLAG_SCHED_SET) == 0)
 562         {
 563           INTERNAL_SYSCALL (sched_getparam, scerr, 2, 0, &pd->schedparam);
 564           pd->flags |= ATTR_FLAG_SCHED_SET;
 565         }
 566
 567       /* Check for valid priorities.  */
 568       int minprio = INTERNAL_SYSCALL (sched_get_priority_min, scerr, 1,
 569                                       iattr->schedpolicy);
 570       int maxprio = INTERNAL_SYSCALL (sched_get_priority_max, scerr, 1,
 571                                       iattr->schedpolicy);
 572       if (pd->schedparam.sched_priority < minprio
 573           || pd->schedparam.sched_priority > maxprio)
 574         {
 575           /* Perhaps a thread wants to change the IDs and if waiting
 576              for this stillborn thread.  */
 577           if (__builtin_expect (atomic_exchange_acq (&pd->setxid_futex, 0)
 578                                 == -2, 0))
 579             lll_futex_wake (&pd->setxid_futex, 1, LLL_PRIVATE);
 580
 581           __deallocate_stack (pd);
 582
 583           retval = EINVAL;
 584           goto out;
 585         }
 586     }
 587
 588   /* Pass the descriptor to the caller.  */
 589   *newthread = (pthread_t) pd;
 590
 591   LIBC_PROBE (pthread_create, 4, newthread, attr, start_routine, arg);
 592
 593   /* Start the thread.  */
 594   retval = create_thread (pd, iattr, STACK_VARIABLES_ARGS);
 595
 596  out:
 597   if (__glibc_unlikely (free_cpuset))
 598     free (default_attr.cpuset);
 599
 600   return retval;
 601 }
 602 versioned_symbol (libpthread, __pthread_create_2_1, pthread_create, GLIBC_2_1);
 603
 604
 605 #if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
 606 int
 607 __pthread_create_2_0 (newthread, attr, start_routine, arg)
 608      pthread_t *newthread;
 609      const pthread_attr_t *attr;
 610      void *(*start_routine) (void *);
 611      void *arg;
 612 {
 613   /* The ATTR attribute is not really of type `pthread_attr_t *'.  It has
 614      the old size and access to the new members might crash the program.
 615      We convert the struct now.  */
 616   struct pthread_attr new_attr;
 617
 618   if (attr != NULL)
 619     {
 620       struct pthread_attr *iattr = (struct pthread_attr *) attr;
 621       size_t ps = __getpagesize ();
 622
 623       /* Copy values from the user-provided attributes.  */
 624       new_attr.schedparam = iattr->schedparam;
 625       new_attr.schedpolicy = iattr->schedpolicy;
 626       new_attr.flags = iattr->flags;
 627
 628       /* Fill in default values for the fields not present in the old
 629          implementation.  */
 630       new_attr.guardsize = ps;
 631       new_attr.stackaddr = NULL;
 632       new_attr.stacksize = 0;
 633       new_attr.cpuset = NULL;
 634
 635       /* We will pass this value on to the real implementation.  */
 636       attr = (pthread_attr_t *) &new_attr;
 637     }
 638
 639   return __pthread_create_2_1 (newthread, attr, start_routine, arg);
 640 }
 641 compat_symbol (libpthread, __pthread_create_2_0, pthread_create,
 642                GLIBC_2_0);
 643 #endif
 644 \f
 645 /* Information for libthread_db.  */
 646
 647 #include "../nptl_db/db_info.c"
 648 \f
 649 /* If pthread_create is present, libgcc_eh.a and libsupc++.a expects some other POSIX thread
 650    functions to be present as well.  */
 651 PTHREAD_STATIC_FN_REQUIRE (pthread_mutex_lock)
 652 PTHREAD_STATIC_FN_REQUIRE (pthread_mutex_trylock)
 653 PTHREAD_STATIC_FN_REQUIRE (pthread_mutex_unlock)
 654
 655 PTHREAD_STATIC_FN_REQUIRE (pthread_once)
 656 PTHREAD_STATIC_FN_REQUIRE (pthread_cancel)
 657
 658 PTHREAD_STATIC_FN_REQUIRE (pthread_key_create)
 659 PTHREAD_STATIC_FN_REQUIRE (pthread_key_delete)
 660 PTHREAD_STATIC_FN_REQUIRE (pthread_setspecific)
 661 PTHREAD_STATIC_FN_REQUIRE (pthread_getspecific)