Initial import of modified Linux 2.6.28 tree

Original upstream URL:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y

1 files changed, 1841 insertions, 0 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
new file mode 100644
index 0000000..10e393b
--- /dev/null
+++ b/kernel/exit.c
@@ -0,0 +1,1841 @@
+/*
+ *  linux/kernel/exit.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/capability.h>
+#include <linux/completion.h>
+#include <linux/personality.h>
+#include <linux/tty.h>
+#include <linux/mnt_namespace.h>
+#include <linux/iocontext.h>
+#include <linux/key.h>
+#include <linux/security.h>
+#include <linux/cpu.h>
+#include <linux/acct.h>
+#include <linux/tsacct_kern.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/binfmts.h>
+#include <linux/nsproxy.h>
+#include <linux/pid_namespace.h>
+#include <linux/ptrace.h>
+#include <linux/profile.h>
+#include <linux/mount.h>
+#include <linux/proc_fs.h>
+#include <linux/kthread.h>
+#include <linux/mempolicy.h>
+#include <linux/taskstats_kern.h>
+#include <linux/delayacct.h>
+#include <linux/freezer.h>
+#include <linux/cgroup.h>
+#include <linux/syscalls.h>
+#include <linux/signal.h>
+#include <linux/posix-timers.h>
+#include <linux/cn_proc.h>
+#include <linux/mutex.h>
+#include <linux/futex.h>
+#include <linux/pipe_fs_i.h>
+#include <linux/audit.h> /* for audit_free() */
+#include <linux/resource.h>
+#include <linux/blkdev.h>
+#include <linux/task_io_accounting_ops.h>
+#include <linux/tracehook.h>
+#include <trace/sched.h>
+
+#include <asm/uaccess.h>
+#include <asm/unistd.h>
+#include <asm/pgtable.h>
+#include <asm/mmu_context.h>
+
+static void exit_mm(struct task_struct * tsk);
+
+static inline int task_detached(struct task_struct *p)
+{
+	return p->exit_signal == -1;
+}
+
+static void __unhash_process(struct task_struct *p)
+{
+	nr_threads--;
+	detach_pid(p, PIDTYPE_PID);
+	if (thread_group_leader(p)) {
+		detach_pid(p, PIDTYPE_PGID);
+		detach_pid(p, PIDTYPE_SID);
+
+		list_del_rcu(&p->tasks);
+		__get_cpu_var(process_counts)--;
+	}
+	list_del_rcu(&p->thread_group);
+	list_del_init(&p->sibling);
+}
+
+/*
+ * This function expects the tasklist_lock write-locked.
+ */
+static void __exit_signal(struct task_struct *tsk)
+{
+	struct signal_struct *sig = tsk->signal;
+	struct sighand_struct *sighand;
+
+	BUG_ON(!sig);
+	BUG_ON(!atomic_read(&sig->count));
+
+	sighand = rcu_dereference(tsk->sighand);
+	spin_lock(&sighand->siglock);
+
+	posix_cpu_timers_exit(tsk);
+	if (atomic_dec_and_test(&sig->count))
+		posix_cpu_timers_exit_group(tsk);
+	else {
+		/*
+		 * If there is any task waiting for the group exit
+		 * then notify it:
+		 */
+		if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count)
+			wake_up_process(sig->group_exit_task);
+
+		if (tsk == sig->curr_target)
+			sig->curr_target = next_thread(tsk);
+		/*
+		 * Accumulate here the counters for all threads but the
+		 * group leader as they die, so they can be added into
+		 * the process-wide totals when those are taken.
+		 * The group leader stays around as a zombie as long
+		 * as there are other threads.  When it gets reaped,
+		 * the exit.c code will add its counts into these totals.
+		 * We won't ever get here for the group leader, since it
+		 * will have been the last reference on the signal_struct.
+		 */
+		sig->gtime = cputime_add(sig->gtime, task_gtime(tsk));
+		sig->min_flt += tsk->min_flt;
+		sig->maj_flt += tsk->maj_flt;
+		sig->nvcsw += tsk->nvcsw;
+		sig->nivcsw += tsk->nivcsw;
+		sig->inblock += task_io_get_inblock(tsk);
+		sig->oublock += task_io_get_oublock(tsk);
+		task_io_accounting_add(&sig->ioac, &tsk->ioac);
+		sig = NULL; /* Marker for below. */
+	}
+
+	__unhash_process(tsk);
+
+	/*
+	 * Do this under ->siglock, we can race with another thread
+	 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
+	 */
+	flush_sigqueue(&tsk->pending);
+
+	tsk->signal = NULL;
+	tsk->sighand = NULL;
+	spin_unlock(&sighand->siglock);
+
+	__cleanup_sighand(sighand);
+	clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
+	if (sig) {
+		flush_sigqueue(&sig->shared_pending);
+		taskstats_tgid_free(sig);
+		/*
+		 * Make sure ->signal can't go away under rq->lock,
+		 * see account_group_exec_runtime().
+		 */
+		task_rq_unlock_wait(tsk);
+		__cleanup_signal(sig);
+	}
+}
+
+static void delayed_put_task_struct(struct rcu_head *rhp)
+{
+	struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
+
+	trace_sched_process_free(tsk);
+	put_task_struct(tsk);
+}
+
+
+void release_task(struct task_struct * p)
+{
+	struct task_struct *leader;
+	int zap_leader;
+repeat:
+	tracehook_prepare_release_task(p);
+	atomic_dec(&p->user->processes);
+	proc_flush_task(p);
+	write_lock_irq(&tasklist_lock);
+	tracehook_finish_release_task(p);
+	__exit_signal(p);
+
+	/*
+	 * If we are the last non-leader member of the thread
+	 * group, and the leader is zombie, then notify the
+	 * group leader's parent process. (if it wants notification.)
+	 */
+	zap_leader = 0;
+	leader = p->group_leader;
+	if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {
+		BUG_ON(task_detached(leader));
+		do_notify_parent(leader, leader->exit_signal);
+		/*
+		 * If we were the last child thread and the leader has
+		 * exited already, and the leader's parent ignores SIGCHLD,
+		 * then we are the one who should release the leader.
+		 *
+		 * do_notify_parent() will have marked it self-reaping in
+		 * that case.
+		 */
+		zap_leader = task_detached(leader);
+
+		/*
+		 * This maintains the invariant that release_task()
+		 * only runs on a task in EXIT_DEAD, just for sanity.
+		 */
+		if (zap_leader)
+			leader->exit_state = EXIT_DEAD;
+	}
+
+	write_unlock_irq(&tasklist_lock);
+	release_thread(p);
+	call_rcu(&p->rcu, delayed_put_task_struct);
+
+	p = leader;
+	if (unlikely(zap_leader))
+		goto repeat;
+}
+
+/*
+ * This checks not only the pgrp, but falls back on the pid if no
+ * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
+ * without this...
+ *
+ * The caller must hold rcu lock or the tasklist lock.
+ */
+struct pid *session_of_pgrp(struct pid *pgrp)
+{
+	struct task_struct *p;
+	struct pid *sid = NULL;
+
+	p = pid_task(pgrp, PIDTYPE_PGID);
+	if (p == NULL)
+		p = pid_task(pgrp, PIDTYPE_PID);
+	if (p != NULL)
+		sid = task_session(p);
+
+	return sid;
+}
+
+/*
+ * Determine if a process group is "orphaned", according to the POSIX
+ * definition in 2.2.2.52.  Orphaned process groups are not to be affected
+ * by terminal-generated stop signals.  Newly orphaned process groups are
+ * to receive a SIGHUP and a SIGCONT.
+ *
+ * "I ask you, have you ever known what it is to be an orphan?"
+ */
+static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task)
+{
+	struct task_struct *p;
+
+	do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
+		if ((p == ignored_task) ||
+		    (p->exit_state && thread_group_empty(p)) ||
+		    is_global_init(p->real_parent))
+			continue;
+
+		if (task_pgrp(p->real_parent) != pgrp &&
+		    task_session(p->real_parent) == task_session(p))
+			return 0;
+	} while_each_pid_task(pgrp, PIDTYPE_PGID, p);
+
+	return 1;
+}
+
+int is_current_pgrp_orphaned(void)
+{
+	int retval;
+
+	read_lock(&tasklist_lock);
+	retval = will_become_orphaned_pgrp(task_pgrp(current), NULL);
+	read_unlock(&tasklist_lock);
+
+	return retval;
+}
+
+static int has_stopped_jobs(struct pid *pgrp)
+{
+	int retval = 0;
+	struct task_struct *p;
+
+	do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
+		if (!task_is_stopped(p))
+			continue;
+		retval = 1;
+		break;
+	} while_each_pid_task(pgrp, PIDTYPE_PGID, p);
+	return retval;
+}
+
+/*
+ * Check to see if any process groups have become orphaned as
+ * a result of our exiting, and if they have any stopped jobs,
+ * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
+ */
+static void
+kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent)
+{
+	struct pid *pgrp = task_pgrp(tsk);
+	struct task_struct *ignored_task = tsk;
+
+	if (!parent)
+		 /* exit: our father is in a different pgrp than
+		  * we are and we were the only connection outside.
+		  */
+		parent = tsk->real_parent;
+	else
+		/* reparent: our child is in a different pgrp than
+		 * we are, and it was the only connection outside.
+		 */
+		ignored_task = NULL;
+
+	if (task_pgrp(parent) != pgrp &&
+	    task_session(parent) == task_session(tsk) &&
+	    will_become_orphaned_pgrp(pgrp, ignored_task) &&
+	    has_stopped_jobs(pgrp)) {
+		__kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp);
+		__kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp);
+	}
+}
+
+/**
+ * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd
+ *
+ * If a kernel thread is launched as a result of a system call, or if
+ * it ever exits, it should generally reparent itself to kthreadd so it
+ * isn't in the way of other processes and is correctly cleaned up on exit.
+ *
+ * The various task state such as scheduling policy and priority may have
+ * been inherited from a user process, so we reset them to sane values here.
+ *
+ * NOTE that reparent_to_kthreadd() gives the caller full capabilities.
+ */
+static void reparent_to_kthreadd(void)
+{
+	write_lock_irq(&tasklist_lock);
+
+	ptrace_unlink(current);
+	/* Reparent to init */
+	current->real_parent = current->parent = kthreadd_task;
+	list_move_tail(&current->sibling, &current->real_parent->children);
+
+	/* Set the exit signal to SIGCHLD so we signal init on exit */
+	current->exit_signal = SIGCHLD;
+
+	if (task_nice(current) < 0)
+		set_user_nice(current, 0);
+	/* cpus_allowed? */
+	/* rt_priority? */
+	/* signals? */
+	security_task_reparent_to_init(current);
+	memcpy(current->signal->rlim, init_task.signal->rlim,
+	       sizeof(current->signal->rlim));
+	atomic_inc(&(INIT_USER->__count));
+	write_unlock_irq(&tasklist_lock);
+	switch_uid(INIT_USER);
+}
+
+void __set_special_pids(struct pid *pid)
+{
+	struct task_struct *curr = current->group_leader;
+	pid_t nr = pid_nr(pid);
+
+	if (task_session(curr) != pid) {
+		change_pid(curr, PIDTYPE_SID, pid);
+		set_task_session(curr, nr);
+	}
+	if (task_pgrp(curr) != pid) {
+		change_pid(curr, PIDTYPE_PGID, pid);
+		set_task_pgrp(curr, nr);
+	}
+}
+
+static void set_special_pids(struct pid *pid)
+{
+	write_lock_irq(&tasklist_lock);
+	__set_special_pids(pid);
+	write_unlock_irq(&tasklist_lock);
+}
+
+/*
+ * Let kernel threads use this to say that they
+ * allow a certain signal (since daemonize() will
+ * have disabled all of them by default).
+ */
+int allow_signal(int sig)
+{
+	if (!valid_signal(sig) || sig < 1)
+		return -EINVAL;
+
+	spin_lock_irq(&current->sighand->siglock);
+	sigdelset(&current->blocked, sig);
+	if (!current->mm) {
+		/* Kernel threads handle their own signals.
+		   Let the signal code know it'll be handled, so
+		   that they don't get converted to SIGKILL or
+		   just silently dropped */
+		current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;
+	}
+	recalc_sigpending();
+	spin_unlock_irq(&current->sighand->siglock);
+	return 0;
+}
+
+EXPORT_SYMBOL(allow_signal);
+
+int disallow_signal(int sig)
+{
+	if (!valid_signal(sig) || sig < 1)
+		return -EINVAL;
+
+	spin_lock_irq(&current->sighand->siglock);
+	current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN;
+	recalc_sigpending();
+	spin_unlock_irq(&current->sighand->siglock);
+	return 0;
+}
+
+EXPORT_SYMBOL(disallow_signal);
+
+/*
+ *	Put all the gunge required to become a kernel thread without
+ *	attached user resources in one place where it belongs.
+ */
+
+void daemonize(const char *name, ...)
+{
+	va_list args;
+	struct fs_struct *fs;
+	sigset_t blocked;
+
+	va_start(args, name);
+	vsnprintf(current->comm, sizeof(current->comm), name, args);
+	va_end(args);
+
+	/*
+	 * If we were started as result of loading a module, close all of the
+	 * user space pages.  We don't need them, and if we didn't close them
+	 * they would be locked into memory.
+	 */
+	exit_mm(current);
+	/*
+	 * We don't want to have TIF_FREEZE set if the system-wide hibernation
+	 * or suspend transition begins right now.
+	 */
+	current->flags |= (PF_NOFREEZE | PF_KTHREAD);
+
+	if (current->nsproxy != &init_nsproxy) {
+		get_nsproxy(&init_nsproxy);
+		switch_task_namespaces(current, &init_nsproxy);
+	}
+	set_special_pids(&init_struct_pid);
+	proc_clear_tty(current);
+
+	/* Block and flush all signals */
+	sigfillset(&blocked);
+	sigprocmask(SIG_BLOCK, &blocked, NULL);
+	flush_signals(current);
+
+	/* Become as one with the init task */
+
+	exit_fs(current);	/* current->fs->count--; */
+	fs = init_task.fs;
+	current->fs = fs;
+	atomic_inc(&fs->count);
+
+	exit_files(current);
+	current->files = init_task.files;
+	atomic_inc(&current->files->count);
+
+	reparent_to_kthreadd();
+}
+
+EXPORT_SYMBOL(daemonize);
+
+static void close_files(struct files_struct * files)
+{
+	int i, j;
+	struct fdtable *fdt;
+
+	j = 0;
+
+	/*
+	 * It is safe to dereference the fd table without RCU or
+	 * ->file_lock because this is the last reference to the
+	 * files structure.
+	 */
+	fdt = files_fdtable(files);
+	for (;;) {
+		unsigned long set;
+		i = j * __NFDBITS;
+		if (i >= fdt->max_fds)
+			break;
+		set = fdt->open_fds->fds_bits[j++];
+		while (set) {
+			if (set & 1) {
+				struct file * file = xchg(&fdt->fd[i], NULL);
+				if (file) {
+					filp_close(file, files);
+					cond_resched();
+				}
+			}
+			i++;
+			set >>= 1;
+		}
+	}
+}
+
+struct files_struct *get_files_struct(struct task_struct *task)
+{
+	struct files_struct *files;
+
+	task_lock(task);
+	files = task->files;
+	if (files)
+		atomic_inc(&files->count);
+	task_unlock(task);
+
+	return files;
+}
+
+void put_files_struct(struct files_struct *files)
+{
+	struct fdtable *fdt;
+
+	if (atomic_dec_and_test(&files->count)) {
+		close_files(files);
+		/*
+		 * Free the fd and fdset arrays if we expanded them.
+		 * If the fdtable was embedded, pass files for freeing
+		 * at the end of the RCU grace period. Otherwise,
+		 * you can free files immediately.
+		 */
+		fdt = files_fdtable(files);
+		if (fdt != &files->fdtab)
+			kmem_cache_free(files_cachep, files);
+		free_fdtable(fdt);
+	}
+}
+
+void reset_files_struct(struct files_struct *files)
+{
+	struct task_struct *tsk = current;
+	struct files_struct *old;
+
+	old = tsk->files;
+	task_lock(tsk);
+	tsk->files = files;
+	task_unlock(tsk);
+	put_files_struct(old);
+}
+
+void exit_files(struct task_struct *tsk)
+{
+	struct files_struct * files = tsk->files;
+
+	if (files) {
+		task_lock(tsk);
+		tsk->files = NULL;
+		task_unlock(tsk);
+		put_files_struct(files);
+	}
+}
+
+void put_fs_struct(struct fs_struct *fs)
+{
+	/* No need to hold fs->lock if we are killing it */
+	if (atomic_dec_and_test(&fs->count)) {
+		path_put(&fs->root);
+		path_put(&fs->pwd);
+		kmem_cache_free(fs_cachep, fs);
+	}
+}
+
+void exit_fs(struct task_struct *tsk)
+{
+	struct fs_struct * fs = tsk->fs;
+
+	if (fs) {
+		task_lock(tsk);
+		tsk->fs = NULL;
+		task_unlock(tsk);
+		put_fs_struct(fs);
+	}
+}
+
+EXPORT_SYMBOL_GPL(exit_fs);
+
+#ifdef CONFIG_MM_OWNER
+/*
+ * Task p is exiting and it owned mm, lets find a new owner for it
+ */
+static inline int
+mm_need_new_owner(struct mm_struct *mm, struct task_struct *p)
+{
+	/*
+	 * If there are other users of the mm and the owner (us) is exiting
+	 * we need to find a new owner to take on the responsibility.
+	 */
+	if (atomic_read(&mm->mm_users) <= 1)
+		return 0;
+	if (mm->owner != p)
+		return 0;
+	return 1;
+}
+
+void mm_update_next_owner(struct mm_struct *mm)
+{
+	struct task_struct *c, *g, *p = current;
+
+retry:
+	if (!mm_need_new_owner(mm, p))
+		return;
+
+	read_lock(&tasklist_lock);
+	/*
+	 * Search in the children
+	 */
+	list_for_each_entry(c, &p->children, sibling) {
+		if (c->mm == mm)
+			goto assign_new_owner;
+	}
+
+	/*
+	 * Search in the siblings
+	 */
+	list_for_each_entry(c, &p->parent->children, sibling) {
+		if (c->mm == mm)
+			goto assign_new_owner;
+	}
+
+	/*
+	 * Search through everything else. We should not get
+	 * here often
+	 */
+	do_each_thread(g, c) {
+		if (c->mm == mm)
+			goto assign_new_owner;
+	} while_each_thread(g, c);
+
+	read_unlock(&tasklist_lock);
+	/*
+	 * We found no owner yet mm_users > 1: this implies that we are
+	 * most likely racing with swapoff (try_to_unuse()) or /proc or
+	 * ptrace or page migration (get_task_mm()).  Mark owner as NULL,
+	 * so that subsystems can understand the callback and take action.
+	 */
+	down_write(&mm->mmap_sem);
+	cgroup_mm_owner_callbacks(mm->owner, NULL);
+	mm->owner = NULL;
+	up_write(&mm->mmap_sem);
+	return;
+
+assign_new_owner:
+	BUG_ON(c == p);
+	get_task_struct(c);
+	read_unlock(&tasklist_lock);
+	down_write(&mm->mmap_sem);
+	/*
+	 * The task_lock protects c->mm from changing.
+	 * We always want mm->owner->mm == mm
+	 */
+	task_lock(c);
+	if (c->mm != mm) {
+		task_unlock(c);
+		up_write(&mm->mmap_sem);
+		put_task_struct(c);
+		goto retry;
+	}
+	cgroup_mm_owner_callbacks(mm->owner, c);
+	mm->owner = c;
+	task_unlock(c);
+	up_write(&mm->mmap_sem);
+	put_task_struct(c);
+}
+#endif /* CONFIG_MM_OWNER */
+
+/*
+ * Turn us into a lazy TLB process if we
+ * aren't already..
+ */
+static void exit_mm(struct task_struct * tsk)
+{
+	struct mm_struct *mm = tsk->mm;
+	struct core_state *core_state;
+
+	mm_release(tsk, mm);
+	if (!mm)
+		return;
+	/*
+	 * Serialize with any possible pending coredump.
+	 * We must hold mmap_sem around checking core_state
+	 * and clearing tsk->mm.  The core-inducing thread
+	 * will increment ->nr_threads for each thread in the
+	 * group with ->mm != NULL.
+	 */
+	down_read(&mm->mmap_sem);
+	core_state = mm->core_state;
+	if (core_state) {
+		struct core_thread self;
+		up_read(&mm->mmap_sem);
+
+		self.task = tsk;
+		self.next = xchg(&core_state->dumper.next, &self);
+		/*
+		 * Implies mb(), the result of xchg() must be visible
+		 * to core_state->dumper.
+		 */
+		if (atomic_dec_and_test(&core_state->nr_threads))
+			complete(&core_state->startup);
+
+		for (;;) {
+			set_task_state(tsk, TASK_UNINTERRUPTIBLE);
+			if (!self.task) /* see coredump_finish() */
+				break;
+			schedule();
+		}
+		__set_task_state(tsk, TASK_RUNNING);
+		down_read(&mm->mmap_sem);
+	}
+	atomic_inc(&mm->mm_count);
+	BUG_ON(mm != tsk->active_mm);
+	/* more a memory barrier than a real lock */
+	task_lock(tsk);
+	tsk->mm = NULL;
+	up_read(&mm->mmap_sem);
+	enter_lazy_tlb(mm, current);
+	/* We don't want this task to be frozen prematurely */
+	clear_freeze_flag(tsk);
+	task_unlock(tsk);
+	mm_update_next_owner(mm);
+	mmput(mm);
+}
+
+/*
+ * Return nonzero if @parent's children should reap themselves.
+ *
+ * Called with write_lock_irq(&tasklist_lock) held.
+ */
+static int ignoring_children(struct task_struct *parent)
+{
+	int ret;
+	struct sighand_struct *psig = parent->sighand;
+	unsigned long flags;
+	spin_lock_irqsave(&psig->siglock, flags);
+	ret = (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
+	       (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT));
+	spin_unlock_irqrestore(&psig->siglock, flags);
+	return ret;
+}
+
+/*
+ * Detach all tasks we were using ptrace on.
+ * Any that need to be release_task'd are put on the @dead list.
+ *
+ * Called with write_lock(&tasklist_lock) held.
+ */
+static void ptrace_exit(struct task_struct *parent, struct list_head *dead)
+{
+	struct task_struct *p, *n;
+	int ign = -1;
+
+	list_for_each_entry_safe(p, n, &parent->ptraced, ptrace_entry) {
+		__ptrace_unlink(p);
+
+		if (p->exit_state != EXIT_ZOMBIE)
+			continue;
+
+		/*
+		 * If it's a zombie, our attachedness prevented normal
+		 * parent notification or self-reaping.  Do notification
+		 * now if it would have happened earlier.  If it should
+		 * reap itself, add it to the @dead list.  We can't call
+		 * release_task() here because we already hold tasklist_lock.
+		 *
+		 * If it's our own child, there is no notification to do.
+		 * But if our normal children self-reap, then this child
+		 * was prevented by ptrace and we must reap it now.
+		 */
+		if (!task_detached(p) && thread_group_empty(p)) {
+			if (!same_thread_group(p->real_parent, parent))
+				do_notify_parent(p, p->exit_signal);
+			else {
+				if (ign < 0)
+					ign = ignoring_children(parent);
+				if (ign)
+					p->exit_signal = -1;
+			}
+		}
+
+		if (task_detached(p)) {
+			/*
+			 * Mark it as in the process of being reaped.
+			 */
+			p->exit_state = EXIT_DEAD;
+			list_add(&p->ptrace_entry, dead);
+		}
+	}
+}
+
+/*
+ * Finish up exit-time ptrace cleanup.
+ *
+ * Called without locks.
+ */
+static void ptrace_exit_finish(struct task_struct *parent,
+			       struct list_head *dead)
+{
+	struct task_struct *p, *n;
+
+	BUG_ON(!list_empty(&parent->ptraced));
+
+	list_for_each_entry_safe(p, n, dead, ptrace_entry) {
+		list_del_init(&p->ptrace_entry);
+		release_task(p);
+	}
+}
+
+static void reparent_thread(struct task_struct *p, struct task_struct *father)
+{
+	if (p->pdeath_signal)
+		/* We already hold the tasklist_lock here.  */
+		group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
+
+	list_move_tail(&p->sibling, &p->real_parent->children);
+
+	/* If this is a threaded reparent there is no need to
+	 * notify anyone anything has happened.
+	 */
+	if (same_thread_group(p->real_parent, father))
+		return;
+
+	/* We don't want people slaying init.  */
+	if (!task_detached(p))
+		p->exit_signal = SIGCHLD;
+
+	/* If we'd notified the old parent about this child's death,
+	 * also notify the new parent.
+	 */
+	if (!ptrace_reparented(p) &&
+	    p->exit_state == EXIT_ZOMBIE &&
+	    !task_detached(p) && thread_group_empty(p))
+		do_notify_parent(p, p->exit_signal);
+
+	kill_orphaned_pgrp(p, father);
+}
+
+/*
+ * When we die, we re-parent all our children.
+ * Try to give them to another thread in our thread
+ * group, and if no such member exists, give it to
+ * the child reaper process (ie "init") in our pid
+ * space.
+ */
+static struct task_struct *find_new_reaper(struct task_struct *father)
+{
+	struct pid_namespace *pid_ns = task_active_pid_ns(father);
+	struct task_struct *thread;
+
+	thread = father;
+	while_each_thread(father, thread) {
+		if (thread->flags & PF_EXITING)
+			continue;
+		if (unlikely(pid_ns->child_reaper == father))
+			pid_ns->child_reaper = thread;
+		return thread;
+	}
+
+	if (unlikely(pid_ns->child_reaper == father)) {
+		write_unlock_irq(&tasklist_lock);
+		if (unlikely(pid_ns == &init_pid_ns))
+			panic("Attempted to kill init!");
+
+		zap_pid_ns_processes(pid_ns);
+		write_lock_irq(&tasklist_lock);
+		/*
+		 * We can not clear ->child_reaper or leave it alone.
+		 * There may by stealth EXIT_DEAD tasks on ->children,
+		 * forget_original_parent() must move them somewhere.
+		 */
+		pid_ns->child_reaper = init_pid_ns.child_reaper;
+	}
+
+	return pid_ns->child_reaper;
+}
+
+static void forget_original_parent(struct task_struct *father)
+{
+	struct task_struct *p, *n, *reaper;
+	LIST_HEAD(ptrace_dead);
+
+	write_lock_irq(&tasklist_lock);
+	reaper = find_new_reaper(father);
+	/*
+	 * First clean up ptrace if we were using it.
+	 */
+	ptrace_exit(father, &ptrace_dead);
+
+	list_for_each_entry_safe(p, n, &father->children, sibling) {
+		p->real_parent = reaper;
+		if (p->parent == father) {
+			BUG_ON(p->ptrace);
+			p->parent = p->real_parent;
+		}
+		reparent_thread(p, father);
+	}
+
+	write_unlock_irq(&tasklist_lock);
+	BUG_ON(!list_empty(&father->children));
+
+	ptrace_exit_finish(father, &ptrace_dead);
+}
+
+/*
+ * Send signals to all our closest relatives so that they know
+ * to properly mourn us..
+ */
+static void exit_notify(struct task_struct *tsk, int group_dead)
+{
+	int signal;
+	void *cookie;
+
+	/*
+	 * This does two things:
+	 *
+  	 * A.  Make init inherit all the child processes
+	 * B.  Check to see if any process groups have become orphaned
+	 *	as a result of our exiting, and if they have any stopped
+	 *	jobs, send them a SIGHUP and then a SIGCONT.  (POSIX 3.2.2.2)
+	 */
+	forget_original_parent(tsk);
+	exit_task_namespaces(tsk);
+
+	write_lock_irq(&tasklist_lock);
+	if (group_dead)
+		kill_orphaned_pgrp(tsk->group_leader, NULL);
+
+	/* Let father know we died
+	 *
+	 * Thread signals are configurable, but you aren't going to use
+	 * that to send signals to arbitary processes.
+	 * That stops right now.
+	 *
+	 * If the parent exec id doesn't match the exec id we saved
+	 * when we started then we know the parent has changed security
+	 * domain.
+	 *
+	 * If our self_exec id doesn't match our parent_exec_id then
+	 * we have changed execution domain as these two values started
+	 * the same after a fork.
+	 */
+	if (tsk->exit_signal != SIGCHLD && !task_detached(tsk) &&
+	    (tsk->parent_exec_id != tsk->real_parent->self_exec_id ||
+	     tsk->self_exec_id != tsk->parent_exec_id) &&
+	    !capable(CAP_KILL))
+		tsk->exit_signal = SIGCHLD;
+
+	signal = tracehook_notify_death(tsk, &cookie, group_dead);
+	if (signal >= 0)
+		signal = do_notify_parent(tsk, signal);
+
+	tsk->exit_state = signal == DEATH_REAP ? EXIT_DEAD : EXIT_ZOMBIE;
+
+	/* mt-exec, de_thread() is waiting for us */
+	if (thread_group_leader(tsk) &&
+	    tsk->signal->group_exit_task &&
+	    tsk->signal->notify_count < 0)
+		wake_up_process(tsk->signal->group_exit_task);
+
+	write_unlock_irq(&tasklist_lock);
+
+	tracehook_report_death(tsk, signal, cookie, group_dead);
+
+	/* If the process is dead, release it - nobody will wait for it */
+	if (signal == DEATH_REAP)
+		release_task(tsk);
+}
+
+#ifdef CONFIG_DEBUG_STACK_USAGE
+static void check_stack_usage(void)
+{
+	static DEFINE_SPINLOCK(low_water_lock);
+	static int lowest_to_date = THREAD_SIZE;
+	unsigned long *n = end_of_stack(current);
+	unsigned long free;
+
+	while (*n == 0)
+		n++;
+	free = (unsigned long)n - (unsigned long)end_of_stack(current);
+
+	if (free >= lowest_to_date)
+		return;
+
+	spin_lock(&low_water_lock);
+	if (free < lowest_to_date) {
+		printk(KERN_WARNING "%s used greatest stack depth: %lu bytes "
+				"left\n",
+				current->comm, free);
+		lowest_to_date = free;
+	}
+	spin_unlock(&low_water_lock);
+}
+#else
+static inline void check_stack_usage(void) {}
+#endif
+
+NORET_TYPE void do_exit(long code)
+{
+	struct task_struct *tsk = current;
+	int group_dead;
+
+	profile_task_exit(tsk);
+
+	WARN_ON(atomic_read(&tsk->fs_excl));
+
+	if (unlikely(in_interrupt()))
+		panic("Aiee, killing interrupt handler!");
+	if (unlikely(!tsk->pid))
+		panic("Attempted to kill the idle task!");
+
+	tracehook_report_exit(&code);
+
+	/*
+	 * We're taking recursive faults here in do_exit. Safest is to just
+	 * leave this task alone and wait for reboot.
+	 */
+	if (unlikely(tsk->flags & PF_EXITING)) {
+		printk(KERN_ALERT
+			"Fixing recursive fault but reboot is needed!\n");
+		/*
+		 * We can do this unlocked here. The futex code uses
+		 * this flag just to verify whether the pi state
+		 * cleanup has been done or not. In the worst case it
+		 * loops once more. We pretend that the cleanup was
+		 * done as there is no way to return. Either the
+		 * OWNER_DIED bit is set by now or we push the blocked
+		 * task into the wait for ever nirwana as well.
+		 */
+		tsk->flags |= PF_EXITPIDONE;
+		if (tsk->io_context)
+			exit_io_context();
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		schedule();
+	}
+
+	exit_signals(tsk);  /* sets PF_EXITING */
+	/*
+	 * tsk->flags are checked in the futex code to protect against
+	 * an exiting task cleaning up the robust pi futexes.
+	 */
+	smp_mb();
+	spin_unlock_wait(&tsk->pi_lock);
+
+	if (unlikely(in_atomic()))
+		printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
+				current->comm, task_pid_nr(current),
+				preempt_count());
+
+	acct_update_integrals(tsk);
+	if (tsk->mm) {
+		update_hiwater_rss(tsk->mm);
+		update_hiwater_vm(tsk->mm);
+	}
+	group_dead = atomic_dec_and_test(&tsk->signal->live);
+	if (group_dead) {
+		hrtimer_cancel(&tsk->signal->real_timer);
+		exit_itimers(tsk->signal);
+	}
+	acct_collect(code, group_dead);
+	if (group_dead)
+		tty_audit_exit();
+	if (unlikely(tsk->audit_context))
+		audit_free(tsk);
+
+	tsk->exit_code = code;
+	taskstats_exit(tsk, group_dead);
+
+	exit_mm(tsk);
+
+	if (group_dead)
+		acct_process();
+	trace_sched_process_exit(tsk);
+
+	exit_sem(tsk);
+	exit_files(tsk);
+	exit_fs(tsk);
+	check_stack_usage();
+	exit_thread();
+	cgroup_exit(tsk, 1);
+	exit_keys(tsk);
+
+	if (group_dead && tsk->signal->leader)
+		disassociate_ctty(1);
+
+	module_put(task_thread_info(tsk)->exec_domain->module);
+	if (tsk->binfmt)
+		module_put(tsk->binfmt->module);
+
+	proc_exit_connector(tsk);
+	exit_notify(tsk, group_dead);
+#ifdef CONFIG_NUMA
+	mpol_put(tsk->mempolicy);
+	tsk->mempolicy = NULL;
+#endif
+#ifdef CONFIG_FUTEX
+	/*
+	 * This must happen late, after the PID is not
+	 * hashed anymore:
+	 */
+	if (unlikely(!list_empty(&tsk->pi_state_list)))
+		exit_pi_state_list(tsk);
+	if (unlikely(current->pi_state_cache))
+		kfree(current->pi_state_cache);
+#endif
+	/*
+	 * Make sure we are holding no locks:
+	 */
+	debug_check_no_locks_held(tsk);
+	/*
+	 * We can do this unlocked here. The futex code uses this flag
+	 * just to verify whether the pi state cleanup has been done
+	 * or not. In the worst case it loops once more.
+	 */
+	tsk->flags |= PF_EXITPIDONE;
+
+	if (tsk->io_context)
+		exit_io_context();
+
+	if (tsk->splice_pipe)
+		__free_pipe_info(tsk->splice_pipe);
+
+	preempt_disable();
+	/* causes final put_task_struct in finish_task_switch(). */
+	tsk->state = TASK_DEAD;
+
+	schedule();
+	BUG();
+	/* Avoid "noreturn function does return".  */
+	for (;;)
+		cpu_relax();	/* For when BUG is null */
+}
+
+EXPORT_SYMBOL_GPL(do_exit);
+
+NORET_TYPE void complete_and_exit(struct completion *comp, long code)
+{
+	if (comp)
+		complete(comp);
+
+	do_exit(code);
+}
+
+EXPORT_SYMBOL(complete_and_exit);
+
+SYSCALL_DEFINE1(exit, int, error_code)
+{
+	do_exit((error_code&0xff)<<8);
+}
+
+/*
+ * Take down every thread in the group.  This is called by fatal signals
+ * as well as by sys_exit_group (below).
+ */
+NORET_TYPE void
+do_group_exit(int exit_code)
+{
+	struct signal_struct *sig = current->signal;
+
+	BUG_ON(exit_code & 0x80); /* core dumps don't get here */
+
+	if (signal_group_exit(sig))
+		exit_code = sig->group_exit_code;
+	else if (!thread_group_empty(current)) {
+		struct sighand_struct *const sighand = current->sighand;
+		spin_lock_irq(&sighand->siglock);
+		if (signal_group_exit(sig))
+			/* Another thread got here before we took the lock.  */
+			exit_code = sig->group_exit_code;
+		else {
+			sig->group_exit_code = exit_code;
+			sig->flags = SIGNAL_GROUP_EXIT;
+			zap_other_threads(current);
+		}
+		spin_unlock_irq(&sighand->siglock);
+	}
+
+	do_exit(exit_code);
+	/* NOTREACHED */
+}
+
+/*
+ * this kills every thread in the thread group. Note that any externally
+ * wait4()-ing process will get the correct exit code - even if this
+ * thread is not the thread group leader.
+ */
+SYSCALL_DEFINE1(exit_group, int, error_code)
+{
+	do_group_exit((error_code & 0xff) << 8);
+	/* NOTREACHED */
+	return 0;
+}
+
+static struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
+{
+	struct pid *pid = NULL;
+	if (type == PIDTYPE_PID)
+		pid = task->pids[type].pid;
+	else if (type < PIDTYPE_MAX)
+		pid = task->group_leader->pids[type].pid;
+	return pid;
+}
+
+static int eligible_child(enum pid_type type, struct pid *pid, int options,
+			  struct task_struct *p)
+{
+	int err;
+
+	if (type < PIDTYPE_MAX) {
+		if (task_pid_type(p, type) != pid)
+			return 0;
+	}
+
+	/* Wait for all children (clone and not) if __WALL is set;
+	 * otherwise, wait for clone children *only* if __WCLONE is
+	 * set; otherwise, wait for non-clone children *only*.  (Note:
+	 * A "clone" child here is one that reports to its parent
+	 * using a signal other than SIGCHLD.) */
+	if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
+	    && !(options & __WALL))
+		return 0;
+
+	err = security_task_wait(p);
+	if (err)
+		return err;
+
+	return 1;
+}
+
+static int wait_noreap_copyout(struct task_struct *p, pid_t pid, uid_t uid,
+			       int why, int status,
+			       struct siginfo __user *infop,
+			       struct rusage __user *rusagep)
+{
+	int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0;
+
+	put_task_struct(p);
+	if (!retval)
+		retval = put_user(SIGCHLD, &infop->si_signo);
+	if (!retval)
+		retval = put_user(0, &infop->si_errno);
+	if (!retval)
+		retval = put_user((short)why, &infop->si_code);
+	if (!retval)
+		retval = put_user(pid, &infop->si_pid);
+	if (!retval)
+		retval = put_user(uid, &infop->si_uid);
+	if (!retval)
+		retval = put_user(status, &infop->si_status);
+	if (!retval)
+		retval = pid;
+	return retval;
+}
+
+/*
+ * Handle sys_wait4 work for one task in state EXIT_ZOMBIE.  We hold
+ * read_lock(&tasklist_lock) on entry.  If we return zero, we still hold
+ * the lock and this task is uninteresting.  If we return nonzero, we have
+ * released the lock and the system call should return.
+ */
+static int wait_task_zombie(struct task_struct *p, int options,
+			    struct siginfo __user *infop,
+			    int __user *stat_addr, struct rusage __user *ru)
+{
+	unsigned long state;
+	int retval, status, traced;
+	pid_t pid = task_pid_vnr(p);
+
+	if (!likely(options & WEXITED))
+		return 0;
+
+	if (unlikely(options & WNOWAIT)) {
+		uid_t uid = p->uid;
+		int exit_code = p->exit_code;
+		int why, status;
+
+		get_task_struct(p);
+		read_unlock(&tasklist_lock);
+		if ((exit_code & 0x7f) == 0) {
+			why = CLD_EXITED;
+			status = exit_code >> 8;
+		} else {
+			why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;
+			status = exit_code & 0x7f;
+		}
+		return wait_noreap_copyout(p, pid, uid, why,
+					   status, infop, ru);
+	}
+
+	/*
+	 * Try to move the task's state to DEAD
+	 * only one thread is allowed to do this:
+	 */
+	state = xchg(&p->exit_state, EXIT_DEAD);
+	if (state != EXIT_ZOMBIE) {
+		BUG_ON(state != EXIT_DEAD);
+		return 0;
+	}
+
+	traced = ptrace_reparented(p);
+
+	if (likely(!traced)) {
+		struct signal_struct *psig;
+		struct signal_struct *sig;
+		struct task_cputime cputime;
+
+		/*
+		 * The resource counters for the group leader are in its
+		 * own task_struct.  Those for dead threads in the group
+		 * are in its signal_struct, as are those for the child
+		 * processes it has previously reaped.  All these
+		 * accumulate in the parent's signal_struct c* fields.
+		 *
+		 * We don't bother to take a lock here to protect these
+		 * p->signal fields, because they are only touched by
+		 * __exit_signal, which runs with tasklist_lock
+		 * write-locked anyway, and so is excluded here.  We do
+		 * need to protect the access to p->parent->signal fields,
+		 * as other threads in the parent group can be right
+		 * here reaping other children at the same time.
+		 *
+		 * We use thread_group_cputime() to get times for the thread
+		 * group, which consolidates times for all threads in the
+		 * group including the group leader.
+		 */
+		spin_lock_irq(&p->parent->sighand->siglock);
+		psig = p->parent->signal;
+		sig = p->signal;
+		thread_group_cputime(p, &cputime);
+		psig->cutime =
+			cputime_add(psig->cutime,
+			cputime_add(cputime.utime,
+				    sig->cutime));
+		psig->cstime =
+			cputime_add(psig->cstime,
+			cputime_add(cputime.stime,
+				    sig->cstime));
+		psig->cgtime =
+			cputime_add(psig->cgtime,
+			cputime_add(p->gtime,
+			cputime_add(sig->gtime,
+				    sig->cgtime)));
+		psig->cmin_flt +=
+			p->min_flt + sig->min_flt + sig->cmin_flt;
+		psig->cmaj_flt +=
+			p->maj_flt + sig->maj_flt + sig->cmaj_flt;
+		psig->cnvcsw +=
+			p->nvcsw + sig->nvcsw + sig->cnvcsw;
+		psig->cnivcsw +=
+			p->nivcsw + sig->nivcsw + sig->cnivcsw;
+		psig->cinblock +=
+			task_io_get_inblock(p) +
+			sig->inblock + sig->cinblock;
+		psig->coublock +=
+			task_io_get_oublock(p) +
+			sig->oublock + sig->coublock;
+		task_io_accounting_add(&psig->ioac, &p->ioac);
+		task_io_accounting_add(&psig->ioac, &sig->ioac);
+		spin_unlock_irq(&p->parent->sighand->siglock);
+	}
+
+	/*
+	 * Now we are sure this task is interesting, and no other
+	 * thread can reap it because we set its state to EXIT_DEAD.
+	 */
+	read_unlock(&tasklist_lock);
+
+	retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
+	status = (p->signal->flags & SIGNAL_GROUP_EXIT)
+		? p->signal->group_exit_code : p->exit_code;
+	if (!retval && stat_addr)
+		retval = put_user(status, stat_addr);
+	if (!retval && infop)
+		retval = put_user(SIGCHLD, &infop->si_signo);
+	if (!retval && infop)
+		retval = put_user(0, &infop->si_errno);
+	if (!retval && infop) {
+		int why;
+
+		if ((status & 0x7f) == 0) {
+			why = CLD_EXITED;
+			status >>= 8;
+		} else {
+			why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
+			status &= 0x7f;
+		}
+		retval = put_user((short)why, &infop->si_code);
+		if (!retval)
+			retval = put_user(status, &infop->si_status);
+	}
+	if (!retval && infop)
+		retval = put_user(pid, &infop->si_pid);
+	if (!retval && infop)
+		retval = put_user(p->uid, &infop->si_uid);
+	if (!retval)
+		retval = pid;
+
+	if (traced) {
+		write_lock_irq(&tasklist_lock);
+		/* We dropped tasklist, ptracer could die and untrace */
+		ptrace_unlink(p);
+		/*
+		 * If this is not a detached task, notify the parent.
+		 * If it's still not detached after that, don't release
+		 * it now.
+		 */
+		if (!task_detached(p)) {
+			do_notify_parent(p, p->exit_signal);
+			if (!task_detached(p)) {
+				p->exit_state = EXIT_ZOMBIE;
+				p = NULL;
+			}
+		}
+		write_unlock_irq(&tasklist_lock);
+	}
+	if (p != NULL)
+		release_task(p);
+
+	return retval;
+}
+
+/*
+ * Handle sys_wait4 work for one task in state TASK_STOPPED.  We hold
+ * read_lock(&tasklist_lock) on entry.  If we return zero, we still hold
+ * the lock and this task is uninteresting.  If we return nonzero, we have
+ * released the lock and the system call should return.
+ */
+static int wait_task_stopped(int ptrace, struct task_struct *p,
+			     int options, struct siginfo __user *infop,
+			     int __user *stat_addr, struct rusage __user *ru)
+{
+	int retval, exit_code, why;
+	uid_t uid = 0; /* unneeded, required by compiler */
+	pid_t pid;
+
+	if (!(options & WUNTRACED))
+		return 0;
+
+	exit_code = 0;
+	spin_lock_irq(&p->sighand->siglock);
+
+	if (unlikely(!task_is_stopped_or_traced(p)))
+		goto unlock_sig;
+
+	if (!ptrace && p->signal->group_stop_count > 0)
+		/*
+		 * A group stop is in progress and this is the group leader.
+		 * We won't report until all threads have stopped.
+		 */
+		goto unlock_sig;
+
+	exit_code = p->exit_code;
+	if (!exit_code)
+		goto unlock_sig;
+
+	if (!unlikely(options & WNOWAIT))
+		p->exit_code = 0;
+
+	uid = p->uid;
+unlock_sig:
+	spin_unlock_irq(&p->sighand->siglock);
+	if (!exit_code)
+		return 0;
+
+	/*
+	 * Now we are pretty sure this task is interesting.
+	 * Make sure it doesn't get reaped out from under us while we
+	 * give up the lock and then examine it below.  We don't want to
+	 * keep holding onto the tasklist_lock while we call getrusage and
+	 * possibly take page faults for user memory.
+	 */
+	get_task_struct(p);
+	pid = task_pid_vnr(p);
+	why = ptrace ? CLD_TRAPPED : CLD_STOPPED;
+	read_unlock(&tasklist_lock);
+
+	if (unlikely(options & WNOWAIT))
+		return wait_noreap_copyout(p, pid, uid,
+					   why, exit_code,
+					   infop, ru);
+
+	retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
+	if (!retval && stat_addr)
+		retval = put_user((exit_code << 8) | 0x7f, stat_addr);
+	if (!retval && infop)
+		retval = put_user(SIGCHLD, &infop->si_signo);
+	if (!retval && infop)
+		retval = put_user(0, &infop->si_errno);
+	if (!retval && infop)
+		retval = put_user((short)why, &infop->si_code);
+	if (!retval && infop)
+		retval = put_user(exit_code, &infop->si_status);
+	if (!retval && infop)
+		retval = put_user(pid, &infop->si_pid);
+	if (!retval && infop)
+		retval = put_user(uid, &infop->si_uid);
+	if (!retval)
+		retval = pid;
+	put_task_struct(p);
+
+	BUG_ON(!retval);
+	return retval;
+}
+
+/*
+ * Handle do_wait work for one task in a live, non-stopped state.
+ * read_lock(&tasklist_lock) on entry.  If we return zero, we still hold
+ * the lock and this task is uninteresting.  If we return nonzero, we have
+ * released the lock and the system call should return.
+ */
+static int wait_task_continued(struct task_struct *p, int options,
+			       struct siginfo __user *infop,
+			       int __user *stat_addr, struct rusage __user *ru)
+{
+	int retval;
+	pid_t pid;
+	uid_t uid;
+
+	if (!unlikely(options & WCONTINUED))
+		return 0;
+
+	if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
+		return 0;
+
+	spin_lock_irq(&p->sighand->siglock);
+	/* Re-check with the lock held.  */
+	if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
+		spin_unlock_irq(&p->sighand->siglock);
+		return 0;
+	}
+	if (!unlikely(options & WNOWAIT))
+		p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
+	spin_unlock_irq(&p->sighand->siglock);
+
+	pid = task_pid_vnr(p);
+	uid = p->uid;
+	get_task_struct(p);
+	read_unlock(&tasklist_lock);
+
+	if (!infop) {
+		retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
+		put_task_struct(p);
+		if (!retval && stat_addr)
+			retval = put_user(0xffff, stat_addr);
+		if (!retval)
+			retval = pid;
+	} else {
+		retval = wait_noreap_copyout(p, pid, uid,
+					     CLD_CONTINUED, SIGCONT,
+					     infop, ru);
+		BUG_ON(retval == 0);
+	}
+
+	return retval;
+}
+
+/*
+ * Consider @p for a wait by @parent.
+ *
+ * -ECHILD should be in *@notask_error before the first call.
+ * Returns nonzero for a final return, when we have unlocked tasklist_lock.
+ * Returns zero if the search for a child should continue;
+ * then *@notask_error is 0 if @p is an eligible child,
+ * or another error from security_task_wait(), or still -ECHILD.
+ */
+static int wait_consider_task(struct task_struct *parent, int ptrace,
+			      struct task_struct *p, int *notask_error,
+			      enum pid_type type, struct pid *pid, int options,
+			      struct siginfo __user *infop,
+			      int __user *stat_addr, struct rusage __user *ru)
+{
+	int ret = eligible_child(type, pid, options, p);
+	if (!ret)
+		return ret;
+
+	if (unlikely(ret < 0)) {
+		/*
+		 * If we have not yet seen any eligible child,
+		 * then let this error code replace -ECHILD.
+		 * A permission error will give the user a clue
+		 * to look for security policy problems, rather
+		 * than for mysterious wait bugs.
+		 */
+		if (*notask_error)
+			*notask_error = ret;
+	}
+
+	if (likely(!ptrace) && unlikely(p->ptrace)) {
+		/*
+		 * This child is hidden by ptrace.
+		 * We aren't allowed to see it now, but eventually we will.
+		 */
+		*notask_error = 0;
+		return 0;
+	}
+
+	if (p->exit_state == EXIT_DEAD)
+		return 0;
+
+	/*
+	 * We don't reap group leaders with subthreads.
+	 */
+	if (p->exit_state == EXIT_ZOMBIE && !delay_group_leader(p))
+		return wait_task_zombie(p, options, infop, stat_addr, ru);
+
+	/*
+	 * It's stopped or running now, so it might
+	 * later continue, exit, or stop again.
+	 */
+	*notask_error = 0;
+
+	if (task_is_stopped_or_traced(p))
+		return wait_task_stopped(ptrace, p, options,
+					 infop, stat_addr, ru);
+
+	return wait_task_continued(p, options, infop, stat_addr, ru);
+}
+
+/*
+ * Do the work of do_wait() for one thread in the group, @tsk.
+ *
+ * -ECHILD should be in *@notask_error before the first call.
+ * Returns nonzero for a final return, when we have unlocked tasklist_lock.
+ * Returns zero if the search for a child should continue; then
+ * *@notask_error is 0 if there were any eligible children,
+ * or another error from security_task_wait(), or still -ECHILD.
+ */
+static int do_wait_thread(struct task_struct *tsk, int *notask_error,
+			  enum pid_type type, struct pid *pid, int options,
+			  struct siginfo __user *infop, int __user *stat_addr,
+			  struct rusage __user *ru)
+{
+	struct task_struct *p;
+
+	list_for_each_entry(p, &tsk->children, sibling) {
+		/*
+		 * Do not consider detached threads.
+		 */
+		if (!task_detached(p)) {
+			int ret = wait_consider_task(tsk, 0, p, notask_error,
+						     type, pid, options,
+						     infop, stat_addr, ru);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int ptrace_do_wait(struct task_struct *tsk, int *notask_error,
+			  enum pid_type type, struct pid *pid, int options,
+			  struct siginfo __user *infop, int __user *stat_addr,
+			  struct rusage __user *ru)
+{
+	struct task_struct *p;
+
+	/*
+	 * Traditionally we see ptrace'd stopped tasks regardless of options.
+	 */
+	options |= WUNTRACED;
+
+	list_for_each_entry(p, &tsk->ptraced, ptrace_entry) {
+		int ret = wait_consider_task(tsk, 1, p, notask_error,
+					     type, pid, options,
+					     infop, stat_addr, ru);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static long do_wait(enum pid_type type, struct pid *pid, int options,
+		    struct siginfo __user *infop, int __user *stat_addr,
+		    struct rusage __user *ru)
+{
+	DECLARE_WAITQUEUE(wait, current);
+	struct task_struct *tsk;
+	int retval;
+
+	trace_sched_process_wait(pid);
+
+	add_wait_queue(&current->signal->wait_chldexit,&wait);
+repeat:
+	/*
+	 * If there is nothing that can match our critiera just get out.
+	 * We will clear @retval to zero if we see any child that might later
+	 * match our criteria, even if we are not able to reap it yet.
+	 */
+	retval = -ECHILD;
+	if ((type < PIDTYPE_MAX) && (!pid || hlist_empty(&pid->tasks[type])))
+		goto end;
+
+	current->state = TASK_INTERRUPTIBLE;
+	read_lock(&tasklist_lock);
+	tsk = current;
+	do {
+		int tsk_result = do_wait_thread(tsk, &retval,
+						type, pid, options,
+						infop, stat_addr, ru);
+		if (!tsk_result)
+			tsk_result = ptrace_do_wait(tsk, &retval,
+						    type, pid, options,
+						    infop, stat_addr, ru);
+		if (tsk_result) {
+			/*
+			 * tasklist_lock is unlocked and we have a final result.
+			 */
+			retval = tsk_result;
+			goto end;
+		}
+
+		if (options & __WNOTHREAD)
+			break;
+		tsk = next_thread(tsk);
+		BUG_ON(tsk->signal != current->signal);
+	} while (tsk != current);
+	read_unlock(&tasklist_lock);
+
+	if (!retval && !(options & WNOHANG)) {
+		retval = -ERESTARTSYS;
+		if (!signal_pending(current)) {
+			schedule();
+			goto repeat;
+		}
+	}
+
+end:
+	current->state = TASK_RUNNING;
+	remove_wait_queue(&current->signal->wait_chldexit,&wait);
+	if (infop) {
+		if (retval > 0)
+			retval = 0;
+		else {
+			/*
+			 * For a WNOHANG return, clear out all the fields
+			 * we would set so the user can easily tell the
+			 * difference.
+			 */
+			if (!retval)
+				retval = put_user(0, &infop->si_signo);
+			if (!retval)
+				retval = put_user(0, &infop->si_errno);
+			if (!retval)
+				retval = put_user(0, &infop->si_code);
+			if (!retval)
+				retval = put_user(0, &infop->si_pid);
+			if (!retval)
+				retval = put_user(0, &infop->si_uid);
+			if (!retval)
+				retval = put_user(0, &infop->si_status);
+		}
+	}
+	return retval;
+}
+
+SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
+		infop, int, options, struct rusage __user *, ru)
+{
+	struct pid *pid = NULL;
+	enum pid_type type;
+	long ret;
+
+	if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
+		return -EINVAL;
+	if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
+		return -EINVAL;
+
+	switch (which) {
+	case P_ALL:
+		type = PIDTYPE_MAX;
+		break;
+	case P_PID:
+		type = PIDTYPE_PID;
+		if (upid <= 0)
+			return -EINVAL;
+		break;
+	case P_PGID:
+		type = PIDTYPE_PGID;
+		if (upid <= 0)
+			return -EINVAL;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (type < PIDTYPE_MAX)
+		pid = find_get_pid(upid);
+	ret = do_wait(type, pid, options, infop, NULL, ru);
+	put_pid(pid);
+
+	/* avoid REGPARM breakage on x86: */
+	asmlinkage_protect(5, ret, which, upid, infop, options, ru);
+	return ret;
+}
+
+SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,
+		int, options, struct rusage __user *, ru)
+{
+	struct pid *pid = NULL;
+	enum pid_type type;
+	long ret;
+
+	if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
+			__WNOTHREAD|__WCLONE|__WALL))
+		return -EINVAL;
+
+	if (upid == -1)
+		type = PIDTYPE_MAX;
+	else if (upid < 0) {
+		type = PIDTYPE_PGID;
+		pid = find_get_pid(-upid);
+	} else if (upid == 0) {
+		type = PIDTYPE_PGID;
+		pid = get_pid(task_pgrp(current));
+	} else /* upid > 0 */ {
+		type = PIDTYPE_PID;
+		pid = find_get_pid(upid);
+	}
+
+	ret = do_wait(type, pid, options | WEXITED, NULL, stat_addr, ru);
+	put_pid(pid);
+
+	/* avoid REGPARM breakage on x86: */
+	asmlinkage_protect(4, ret, upid, stat_addr, options, ru);
+	return ret;
+}
+
+#ifdef __ARCH_WANT_SYS_WAITPID
+
+/*
+ * sys_waitpid() remains for compatibility. waitpid() should be
+ * implemented by calling sys_wait4() from libc.a.
+ */
+SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options)
+{
+	return sys_wait4(pid, stat_addr, options, NULL);
+}
+
+#endif