b2e3ee7d07
Stack creation code is changed to call _rtld_get_stack_prot() to get the stack protection right. There is a race where thread is created during dlopen() of dso that requires executable stacks. Then, _rtld_get_stack_prot() may return PROT_READ | PROT_WRITE, but thread is still not linked into the thread list. In this case, the callback misses the thread stack, and rechecks the required protection afterward. Reviewed by: davidxu
289 lines
8.0 KiB
C
289 lines
8.0 KiB
C
/*
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* Copyright (c) 2003 Daniel M. Eischen <deischen@gdeb.com>
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* Copyright (c) 2005, David Xu <davidxu@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice unmodified, this list of conditions, and the following
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* disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include "namespace.h"
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#include <sys/types.h>
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#include <sys/rtprio.h>
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#include <sys/signalvar.h>
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#include <errno.h>
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#include <link.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stddef.h>
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#include <pthread.h>
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#include <pthread_np.h>
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#include "un-namespace.h"
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#include "thr_private.h"
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static int create_stack(struct pthread_attr *pattr);
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static void thread_start(struct pthread *curthread);
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__weak_reference(_pthread_create, pthread_create);
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int
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_pthread_create(pthread_t * thread, const pthread_attr_t * attr,
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void *(*start_routine) (void *), void *arg)
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{
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struct pthread *curthread, *new_thread;
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struct thr_param param;
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struct sched_param sched_param;
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struct rtprio rtp;
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int ret = 0, locked, create_suspended;
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sigset_t set, oset;
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cpuset_t *cpusetp = NULL;
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int cpusetsize = 0;
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int old_stack_prot;
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_thr_check_init();
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/*
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* Tell libc and others now they need lock to protect their data.
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*/
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if (_thr_isthreaded() == 0 && _thr_setthreaded(1))
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return (EAGAIN);
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curthread = _get_curthread();
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if ((new_thread = _thr_alloc(curthread)) == NULL)
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return (EAGAIN);
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memset(¶m, 0, sizeof(param));
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if (attr == NULL || *attr == NULL)
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/* Use the default thread attributes: */
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new_thread->attr = _pthread_attr_default;
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else {
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new_thread->attr = *(*attr);
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cpusetp = new_thread->attr.cpuset;
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cpusetsize = new_thread->attr.cpusetsize;
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new_thread->attr.cpuset = NULL;
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new_thread->attr.cpusetsize = 0;
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}
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if (new_thread->attr.sched_inherit == PTHREAD_INHERIT_SCHED) {
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/* inherit scheduling contention scope */
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if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
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new_thread->attr.flags |= PTHREAD_SCOPE_SYSTEM;
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else
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new_thread->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
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new_thread->attr.prio = curthread->attr.prio;
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new_thread->attr.sched_policy = curthread->attr.sched_policy;
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}
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new_thread->tid = TID_TERMINATED;
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old_stack_prot = _rtld_get_stack_prot();
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if (create_stack(&new_thread->attr) != 0) {
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/* Insufficient memory to create a stack: */
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_thr_free(curthread, new_thread);
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return (EAGAIN);
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}
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/*
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* Write a magic value to the thread structure
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* to help identify valid ones:
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*/
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new_thread->magic = THR_MAGIC;
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new_thread->start_routine = start_routine;
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new_thread->arg = arg;
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new_thread->cancel_enable = 1;
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new_thread->cancel_async = 0;
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/* Initialize the mutex queue: */
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TAILQ_INIT(&new_thread->mutexq);
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TAILQ_INIT(&new_thread->pp_mutexq);
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/* Initialise hooks in the thread structure: */
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if (new_thread->attr.suspend == THR_CREATE_SUSPENDED) {
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new_thread->flags = THR_FLAGS_NEED_SUSPEND;
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create_suspended = 1;
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} else {
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create_suspended = 0;
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}
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new_thread->state = PS_RUNNING;
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if (new_thread->attr.flags & PTHREAD_CREATE_DETACHED)
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new_thread->flags |= THR_FLAGS_DETACHED;
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/* Add the new thread. */
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new_thread->refcount = 1;
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_thr_link(curthread, new_thread);
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/*
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* Handle the race between __pthread_map_stacks_exec and
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* thread linkage.
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*/
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if (old_stack_prot != _rtld_get_stack_prot())
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_thr_stack_fix_protection(new_thread);
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/* Return thread pointer eariler so that new thread can use it. */
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(*thread) = new_thread;
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if (SHOULD_REPORT_EVENT(curthread, TD_CREATE) || cpusetp != NULL) {
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THR_THREAD_LOCK(curthread, new_thread);
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locked = 1;
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} else
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locked = 0;
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param.start_func = (void (*)(void *)) thread_start;
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param.arg = new_thread;
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param.stack_base = new_thread->attr.stackaddr_attr;
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param.stack_size = new_thread->attr.stacksize_attr;
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param.tls_base = (char *)new_thread->tcb;
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param.tls_size = sizeof(struct tcb);
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param.child_tid = &new_thread->tid;
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param.parent_tid = &new_thread->tid;
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param.flags = 0;
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if (new_thread->attr.flags & PTHREAD_SCOPE_SYSTEM)
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param.flags |= THR_SYSTEM_SCOPE;
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if (new_thread->attr.sched_inherit == PTHREAD_INHERIT_SCHED)
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param.rtp = NULL;
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else {
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sched_param.sched_priority = new_thread->attr.prio;
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_schedparam_to_rtp(new_thread->attr.sched_policy,
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&sched_param, &rtp);
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param.rtp = &rtp;
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}
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/* Schedule the new thread. */
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if (create_suspended) {
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SIGFILLSET(set);
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SIGDELSET(set, SIGTRAP);
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__sys_sigprocmask(SIG_SETMASK, &set, &oset);
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new_thread->sigmask = oset;
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SIGDELSET(new_thread->sigmask, SIGCANCEL);
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}
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ret = thr_new(¶m, sizeof(param));
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if (ret != 0) {
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ret = errno;
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/*
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* Translate EPROCLIM into well-known POSIX code EAGAIN.
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*/
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if (ret == EPROCLIM)
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ret = EAGAIN;
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}
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if (create_suspended)
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__sys_sigprocmask(SIG_SETMASK, &oset, NULL);
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if (ret != 0) {
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if (!locked)
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THR_THREAD_LOCK(curthread, new_thread);
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new_thread->state = PS_DEAD;
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new_thread->tid = TID_TERMINATED;
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new_thread->flags |= THR_FLAGS_DETACHED;
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new_thread->refcount--;
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if (new_thread->flags & THR_FLAGS_NEED_SUSPEND) {
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new_thread->cycle++;
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_thr_umtx_wake(&new_thread->cycle, INT_MAX, 0);
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}
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_thr_try_gc(curthread, new_thread); /* thread lock released */
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atomic_add_int(&_thread_active_threads, -1);
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} else if (locked) {
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if (cpusetp != NULL) {
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if (cpuset_setaffinity(CPU_LEVEL_WHICH, CPU_WHICH_TID,
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TID(new_thread), cpusetsize, cpusetp)) {
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ret = errno;
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/* kill the new thread */
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new_thread->force_exit = 1;
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new_thread->flags |= THR_FLAGS_DETACHED;
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_thr_try_gc(curthread, new_thread);
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/* thread lock released */
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goto out;
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}
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}
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_thr_report_creation(curthread, new_thread);
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THR_THREAD_UNLOCK(curthread, new_thread);
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}
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out:
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if (ret)
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(*thread) = 0;
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return (ret);
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}
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static int
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create_stack(struct pthread_attr *pattr)
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{
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int ret;
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/* Check if a stack was specified in the thread attributes: */
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if ((pattr->stackaddr_attr) != NULL) {
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pattr->guardsize_attr = 0;
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pattr->flags |= THR_STACK_USER;
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ret = 0;
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}
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else
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ret = _thr_stack_alloc(pattr);
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return (ret);
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}
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static void
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thread_start(struct pthread *curthread)
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{
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sigset_t set;
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if (curthread->attr.suspend == THR_CREATE_SUSPENDED)
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set = curthread->sigmask;
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/*
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* This is used as a serialization point to allow parent
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* to report 'new thread' event to debugger or tweak new thread's
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* attributes before the new thread does real-world work.
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*/
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THR_LOCK(curthread);
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THR_UNLOCK(curthread);
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if (curthread->force_exit)
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_pthread_exit(PTHREAD_CANCELED);
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if (curthread->attr.suspend == THR_CREATE_SUSPENDED) {
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#if 0
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/* Done in THR_UNLOCK() */
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_thr_ast(curthread);
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#endif
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/*
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* Parent thread have stored signal mask for us,
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* we should restore it now.
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*/
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__sys_sigprocmask(SIG_SETMASK, &set, NULL);
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}
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#ifdef _PTHREAD_FORCED_UNWIND
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curthread->unwind_stackend = (char *)curthread->attr.stackaddr_attr +
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curthread->attr.stacksize_attr;
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#endif
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/* Run the current thread's start routine with argument: */
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_pthread_exit(curthread->start_routine(curthread->arg));
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/* This point should never be reached. */
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PANIC("Thread has resumed after exit");
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}
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