X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fexit.c;h=5962d7ccf24371ed7aedf4832cac0cbd5e9c3820;hb=5da9a0fb673a0ea0a093862f95f6b89b3390c31e;hp=51d1fe3fb7ad5b60666c7f229d6bacd8942479e9;hpb=3296ca27f50ecbd71db1d808c7a72d311027f919;p=safe%2Fjmp%2Flinux-2.6

diff --git a/kernel/exit.c b/kernel/exit.c
index 51d1fe3..5962d7c 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -12,7 +12,6 @@
 #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>
@@ -48,7 +47,9 @@
 #include <linux/tracehook.h>
 #include <linux/fs_struct.h>
 #include <linux/init_task.h>
+#include <linux/perf_event.h>
 #include <trace/events/sched.h>
+#include <linux/hw_breakpoint.h>
 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
@@ -110,9 +111,9 @@ static void __exit_signal(struct task_struct *tsk)
 		 * We won't ever get here for the group leader, since it
 		 * will have been the last reference on the signal_struct.
 		 */
-		sig->utime = cputime_add(sig->utime, task_utime(tsk));
-		sig->stime = cputime_add(sig->stime, task_stime(tsk));
-		sig->gtime = cputime_add(sig->gtime, task_gtime(tsk));
+		sig->utime = cputime_add(sig->utime, tsk->utime);
+		sig->stime = cputime_add(sig->stime, tsk->stime);
+		sig->gtime = cputime_add(sig->gtime, tsk->gtime);
 		sig->min_flt += tsk->min_flt;
 		sig->maj_flt += tsk->maj_flt;
 		sig->nvcsw += tsk->nvcsw;
@@ -154,6 +155,9 @@ static void delayed_put_task_struct(struct rcu_head *rhp)
 {
 	struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
 
+#ifdef CONFIG_PERF_EVENTS
+	WARN_ON_ONCE(tsk->perf_event_ctxp);
+#endif
 	trace_sched_process_free(tsk);
 	put_task_struct(tsk);
 }
@@ -170,6 +174,7 @@ repeat:
 	atomic_dec(&__task_cred(p)->user->processes);
 
 	proc_flush_task(p);
+
 	write_lock_irq(&tasklist_lock);
 	tracehook_finish_release_task(p);
 	__exit_signal(p);
@@ -370,9 +375,8 @@ static void set_special_pids(struct pid *pid)
 }
 
 /*
- * Let kernel threads use this to say that they
- * allow a certain signal (since daemonize() will
- * have disabled all of them by default).
+ * Let kernel threads use this to say that they allow a certain signal.
+ * Must not be used if kthread was cloned with CLONE_SIGHAND.
  */
 int allow_signal(int sig)
 {
@@ -380,14 +384,14 @@ int allow_signal(int sig)
 		return -EINVAL;
 
 	spin_lock_irq(&current->sighand->siglock);
+	/* This is only needed for daemonize()'ed kthreads */
 	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;
-	}
+	/*
+	 * 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;
@@ -586,7 +590,7 @@ retry:
 	/*
 	 * Search in the siblings
 	 */
-	list_for_each_entry(c, &p->parent->children, sibling) {
+	list_for_each_entry(c, &p->real_parent->children, sibling) {
 		if (c->mm == mm)
 			goto assign_new_owner;
 	}
@@ -753,7 +757,7 @@ static void reparent_thread(struct task_struct *father, struct task_struct *p,
 	p->exit_signal = SIGCHLD;
 
 	/* If it has exited notify the new parent about this child's death. */
-	if (!p->ptrace &&
+	if (!task_ptrace(p) &&
 	    p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) {
 		do_notify_parent(p, p->exit_signal);
 		if (task_detached(p)) {
@@ -778,7 +782,7 @@ static void forget_original_parent(struct task_struct *father)
 	list_for_each_entry_safe(p, n, &father->children, sibling) {
 		p->real_parent = reaper;
 		if (p->parent == father) {
-			BUG_ON(p->ptrace);
+			BUG_ON(task_ptrace(p));
 			p->parent = p->real_parent;
 		}
 		reparent_thread(father, p, &dead_children);
@@ -898,6 +902,8 @@ NORET_TYPE void do_exit(long code)
 
 	tracehook_report_exit(&code);
 
+	validate_creds_for_do_exit(tsk);
+
 	/*
 	 * We're taking recursive faults here in do_exit. Safest is to just
 	 * leave this task alone and wait for reboot.
@@ -927,7 +933,7 @@ NORET_TYPE void do_exit(long code)
 	 * an exiting task cleaning up the robust pi futexes.
 	 */
 	smp_mb();
-	spin_unlock_wait(&tsk->pi_lock);
+	raw_spin_unlock_wait(&tsk->pi_lock);
 
 	if (unlikely(in_atomic()))
 		printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
@@ -940,6 +946,8 @@ NORET_TYPE void do_exit(long code)
 	if (group_dead) {
 		hrtimer_cancel(&tsk->signal->real_timer);
 		exit_itimers(tsk->signal);
+		if (tsk->mm)
+			setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm);
 	}
 	acct_collect(code, group_dead);
 	if (group_dead)
@@ -963,26 +971,29 @@ NORET_TYPE void do_exit(long code)
 	exit_thread();
 	cgroup_exit(tsk, 1);
 
-	if (group_dead && tsk->signal->leader)
+	if (group_dead)
 		disassociate_ctty(1);
 
 	module_put(task_thread_info(tsk)->exec_domain->module);
-	if (tsk->binfmt)
-		module_put(tsk->binfmt->module);
 
 	proc_exit_connector(tsk);
+
+	/*
+	 * FIXME: do that only when needed, using sched_exit tracepoint
+	 */
+	flush_ptrace_hw_breakpoint(tsk);
+	/*
+	 * Flush inherited counters to the parent - before the parent
+	 * gets woken up by child-exit notifications.
+	 */
+	perf_event_exit_task(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
@@ -998,12 +1009,15 @@ NORET_TYPE void do_exit(long code)
 	tsk->flags |= PF_EXITPIDONE;
 
 	if (tsk->io_context)
-		exit_io_context();
+		exit_io_context(tsk);
 
 	if (tsk->splice_pipe)
 		__free_pipe_info(tsk->splice_pipe);
 
+	validate_creds_for_do_exit(tsk);
+
 	preempt_disable();
+	exit_rcu();
 	/* causes final put_task_struct in finish_task_switch(). */
 	tsk->state = TASK_DEAD;
 	schedule();
@@ -1073,62 +1087,72 @@ SYSCALL_DEFINE1(exit_group, int, error_code)
 	return 0;
 }
 
-static struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
+struct wait_opts {
+	enum pid_type		wo_type;
+	int			wo_flags;
+	struct pid		*wo_pid;
+
+	struct siginfo __user	*wo_info;
+	int __user		*wo_stat;
+	struct rusage __user	*wo_rusage;
+
+	wait_queue_t		child_wait;
+	int			notask_error;
+};
+
+static inline
+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;
+	if (type != PIDTYPE_PID)
+		task = task->group_leader;
+	return task->pids[type].pid;
 }
 
-static int eligible_child(enum pid_type type, struct pid *pid, int options,
-			  struct task_struct *p)
+static int eligible_pid(struct wait_opts *wo, struct task_struct *p)
 {
-	int err;
-
-	if (type < PIDTYPE_MAX) {
-		if (task_pid_type(p, type) != pid)
-			return 0;
-	}
+	return	wo->wo_type == PIDTYPE_MAX ||
+		task_pid_type(p, wo->wo_type) == wo->wo_pid;
+}
 
+static int eligible_child(struct wait_opts *wo, struct task_struct *p)
+{
+	if (!eligible_pid(wo, p))
+		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))
+	if (((p->exit_signal != SIGCHLD) ^ !!(wo->wo_flags & __WCLONE))
+	    && !(wo->wo_flags & __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)
+static int wait_noreap_copyout(struct wait_opts *wo, struct task_struct *p,
+				pid_t pid, uid_t uid, int why, int status)
 {
-	int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0;
+	struct siginfo __user *infop;
+	int retval = wo->wo_rusage
+		? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 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);
+	infop = wo->wo_info;
+	if (infop) {
+		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;
@@ -1140,19 +1164,18 @@ static int wait_noreap_copyout(struct task_struct *p, pid_t pid, uid_t uid,
  * 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)
+static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
 {
 	unsigned long state;
 	int retval, status, traced;
 	pid_t pid = task_pid_vnr(p);
 	uid_t uid = __task_cred(p)->uid;
+	struct siginfo __user *infop;
 
-	if (!likely(options & WEXITED))
+	if (!likely(wo->wo_flags & WEXITED))
 		return 0;
 
-	if (unlikely(options & WNOWAIT)) {
+	if (unlikely(wo->wo_flags & WNOWAIT)) {
 		int exit_code = p->exit_code;
 		int why, status;
 
@@ -1165,8 +1188,7 @@ static int wait_task_zombie(struct task_struct *p, int options,
 			why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;
 			status = exit_code & 0x7f;
 		}
-		return wait_noreap_copyout(p, pid, uid, why,
-					   status, infop, ru);
+		return wait_noreap_copyout(wo, p, pid, uid, why, status);
 	}
 
 	/*
@@ -1180,11 +1202,15 @@ static int wait_task_zombie(struct task_struct *p, int options,
 	}
 
 	traced = ptrace_reparented(p);
-
-	if (likely(!traced)) {
+	/*
+	 * It can be ptraced but not reparented, check
+	 * !task_detached() to filter out sub-threads.
+	 */
+	if (likely(!traced) && likely(!task_detached(p))) {
 		struct signal_struct *psig;
 		struct signal_struct *sig;
-		struct task_cputime cputime;
+		unsigned long maxrss;
+		cputime_t tgutime, tgstime;
 
 		/*
 		 * The resource counters for the group leader are in its
@@ -1197,25 +1223,25 @@ static int wait_task_zombie(struct task_struct *p, int options,
 		 * 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,
+		 * need to protect the access to 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
+		 * We use thread_group_times() to get times for the thread
 		 * group, which consolidates times for all threads in the
 		 * group including the group leader.
 		 */
-		thread_group_cputime(p, &cputime);
-		spin_lock_irq(&p->parent->sighand->siglock);
-		psig = p->parent->signal;
+		thread_group_times(p, &tgutime, &tgstime);
+		spin_lock_irq(&p->real_parent->sighand->siglock);
+		psig = p->real_parent->signal;
 		sig = p->signal;
 		psig->cutime =
 			cputime_add(psig->cutime,
-			cputime_add(cputime.utime,
+			cputime_add(tgutime,
 				    sig->cutime));
 		psig->cstime =
 			cputime_add(psig->cstime,
-			cputime_add(cputime.stime,
+			cputime_add(tgstime,
 				    sig->cstime));
 		psig->cgtime =
 			cputime_add(psig->cgtime,
@@ -1236,9 +1262,12 @@ static int wait_task_zombie(struct task_struct *p, int options,
 		psig->coublock +=
 			task_io_get_oublock(p) +
 			sig->oublock + sig->coublock;
+		maxrss = max(sig->maxrss, sig->cmaxrss);
+		if (psig->cmaxrss < maxrss)
+			psig->cmaxrss = maxrss;
 		task_io_accounting_add(&psig->ioac, &p->ioac);
 		task_io_accounting_add(&psig->ioac, &sig->ioac);
-		spin_unlock_irq(&p->parent->sighand->siglock);
+		spin_unlock_irq(&p->real_parent->sighand->siglock);
 	}
 
 	/*
@@ -1247,11 +1276,14 @@ static int wait_task_zombie(struct task_struct *p, int options,
 	 */
 	read_unlock(&tasklist_lock);
 
-	retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
+	retval = wo->wo_rusage
+		? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 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 && wo->wo_stat)
+		retval = put_user(status, wo->wo_stat);
+
+	infop = wo->wo_info;
 	if (!retval && infop)
 		retval = put_user(SIGCHLD, &infop->si_signo);
 	if (!retval && infop)
@@ -1319,15 +1351,18 @@ static int *task_stopped_code(struct task_struct *p, bool ptrace)
  * 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)
+static int wait_task_stopped(struct wait_opts *wo,
+				int ptrace, struct task_struct *p)
 {
+	struct siginfo __user *infop;
 	int retval, exit_code, *p_code, why;
 	uid_t uid = 0; /* unneeded, required by compiler */
 	pid_t pid;
 
-	if (!(options & WUNTRACED))
+	/*
+	 * Traditionally we see ptrace'd stopped tasks regardless of options.
+	 */
+	if (!ptrace && !(wo->wo_flags & WUNTRACED))
 		return 0;
 
 	exit_code = 0;
@@ -1341,7 +1376,7 @@ static int wait_task_stopped(int ptrace, struct task_struct *p,
 	if (!exit_code)
 		goto unlock_sig;
 
-	if (!unlikely(options & WNOWAIT))
+	if (!unlikely(wo->wo_flags & WNOWAIT))
 		*p_code = 0;
 
 	/* don't need the RCU readlock here as we're holding a spinlock */
@@ -1363,14 +1398,15 @@ unlock_sig:
 	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);
+	if (unlikely(wo->wo_flags & WNOWAIT))
+		return wait_noreap_copyout(wo, p, pid, uid, why, exit_code);
+
+	retval = wo->wo_rusage
+		? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
+	if (!retval && wo->wo_stat)
+		retval = put_user((exit_code << 8) | 0x7f, wo->wo_stat);
 
-	retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
-	if (!retval && stat_addr)
-		retval = put_user((exit_code << 8) | 0x7f, stat_addr);
+	infop = wo->wo_info;
 	if (!retval && infop)
 		retval = put_user(SIGCHLD, &infop->si_signo);
 	if (!retval && infop)
@@ -1397,15 +1433,13 @@ unlock_sig:
  * 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)
+static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
 {
 	int retval;
 	pid_t pid;
 	uid_t uid;
 
-	if (!unlikely(options & WCONTINUED))
+	if (!unlikely(wo->wo_flags & WCONTINUED))
 		return 0;
 
 	if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
@@ -1417,7 +1451,7 @@ static int wait_task_continued(struct task_struct *p, int options,
 		spin_unlock_irq(&p->sighand->siglock);
 		return 0;
 	}
-	if (!unlikely(options & WNOWAIT))
+	if (!unlikely(wo->wo_flags & WNOWAIT))
 		p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
 	uid = __task_cred(p)->uid;
 	spin_unlock_irq(&p->sighand->siglock);
@@ -1426,17 +1460,17 @@ static int wait_task_continued(struct task_struct *p, int options,
 	get_task_struct(p);
 	read_unlock(&tasklist_lock);
 
-	if (!infop) {
-		retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
+	if (!wo->wo_info) {
+		retval = wo->wo_rusage
+			? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
 		put_task_struct(p);
-		if (!retval && stat_addr)
-			retval = put_user(0xffff, stat_addr);
+		if (!retval && wo->wo_stat)
+			retval = put_user(0xffff, wo->wo_stat);
 		if (!retval)
 			retval = pid;
 	} else {
-		retval = wait_noreap_copyout(p, pid, uid,
-					     CLD_CONTINUED, SIGCONT,
-					     infop, ru);
+		retval = wait_noreap_copyout(wo, p, pid, uid,
+					     CLD_CONTINUED, SIGCONT);
 		BUG_ON(retval == 0);
 	}
 
@@ -1446,22 +1480,20 @@ static int wait_task_continued(struct task_struct *p, int options,
 /*
  * Consider @p for a wait by @parent.
  *
- * -ECHILD should be in *@notask_error before the first call.
+ * -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,
+ * 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)
+static int wait_consider_task(struct wait_opts *wo, int ptrace,
+				struct task_struct *p)
 {
-	int ret = eligible_child(type, pid, options, p);
+	int ret = eligible_child(wo, p);
 	if (!ret)
 		return ret;
 
+	ret = security_task_wait(p);
 	if (unlikely(ret < 0)) {
 		/*
 		 * If we have not yet seen any eligible child,
@@ -1470,17 +1502,17 @@ static int wait_consider_task(struct task_struct *parent, int ptrace,
 		 * to look for security policy problems, rather
 		 * than for mysterious wait bugs.
 		 */
-		if (*notask_error)
-			*notask_error = ret;
+		if (wo->notask_error)
+			wo->notask_error = ret;
 		return 0;
 	}
 
-	if (likely(!ptrace) && unlikely(p->ptrace)) {
+	if (likely(!ptrace) && unlikely(task_ptrace(p))) {
 		/*
 		 * This child is hidden by ptrace.
 		 * We aren't allowed to see it now, but eventually we will.
 		 */
-		*notask_error = 0;
+		wo->notask_error = 0;
 		return 0;
 	}
 
@@ -1491,34 +1523,30 @@ static int wait_consider_task(struct task_struct *parent, int ptrace,
 	 * 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);
+		return wait_task_zombie(wo, p);
 
 	/*
 	 * It's stopped or running now, so it might
 	 * later continue, exit, or stop again.
 	 */
-	*notask_error = 0;
+	wo->notask_error = 0;
 
 	if (task_stopped_code(p, ptrace))
-		return wait_task_stopped(ptrace, p, options,
-					 infop, stat_addr, ru);
+		return wait_task_stopped(wo, ptrace, p);
 
-	return wait_task_continued(p, options, infop, stat_addr, ru);
+	return wait_task_continued(wo, p);
 }
 
 /*
  * Do the work of do_wait() for one thread in the group, @tsk.
  *
- * -ECHILD should be in *@notask_error before the first call.
+ * -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,
+ * ->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)
+static int do_wait_thread(struct wait_opts *wo, struct task_struct *tsk)
 {
 	struct task_struct *p;
 
@@ -1527,9 +1555,7 @@ static int do_wait_thread(struct task_struct *tsk, int *notask_error,
 		 * 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);
+			int ret = wait_consider_task(wo, 0, p);
 			if (ret)
 				return ret;
 		}
@@ -1538,22 +1564,12 @@ static int do_wait_thread(struct task_struct *tsk, int *notask_error,
 	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)
+static int ptrace_do_wait(struct wait_opts *wo, struct task_struct *tsk)
 {
 	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);
+		int ret = wait_consider_task(wo, 1, p);
 		if (ret)
 			return ret;
 	}
@@ -1561,93 +1577,86 @@ static int ptrace_do_wait(struct task_struct *tsk, int *notask_error,
 	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)
+static int child_wait_callback(wait_queue_t *wait, unsigned mode,
+				int sync, void *key)
+{
+	struct wait_opts *wo = container_of(wait, struct wait_opts,
+						child_wait);
+	struct task_struct *p = key;
+
+	if (!eligible_pid(wo, p))
+		return 0;
+
+	if ((wo->wo_flags & __WNOTHREAD) && wait->private != p->parent)
+		return 0;
+
+	return default_wake_function(wait, mode, sync, key);
+}
+
+void __wake_up_parent(struct task_struct *p, struct task_struct *parent)
+{
+	__wake_up_sync_key(&parent->signal->wait_chldexit,
+				TASK_INTERRUPTIBLE, 1, p);
+}
+
+static long do_wait(struct wait_opts *wo)
 {
-	DECLARE_WAITQUEUE(wait, current);
 	struct task_struct *tsk;
 	int retval;
 
-	trace_sched_process_wait(pid);
+	trace_sched_process_wait(wo->wo_pid);
 
-	add_wait_queue(&current->signal->wait_chldexit,&wait);
+	init_waitqueue_func_entry(&wo->child_wait, child_wait_callback);
+	wo->child_wait.private = current;
+	add_wait_queue(&current->signal->wait_chldexit, &wo->child_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.
+	 * We will clear ->notask_error 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;
+	wo->notask_error = -ECHILD;
+	if ((wo->wo_type < PIDTYPE_MAX) &&
+	   (!wo->wo_pid || hlist_empty(&wo->wo_pid->tasks[wo->wo_type])))
+		goto notask;
 
-	current->state = TASK_INTERRUPTIBLE;
+	set_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;
+		retval = do_wait_thread(wo, tsk);
+		if (retval)
+			goto end;
+
+		retval = ptrace_do_wait(wo, tsk);
+		if (retval)
 			goto end;
-		}
 
-		if (options & __WNOTHREAD)
+		if (wo->wo_flags & __WNOTHREAD)
 			break;
-		tsk = next_thread(tsk);
-		BUG_ON(tsk->signal != current->signal);
-	} while (tsk != current);
+	} while_each_thread(current, tsk);
 	read_unlock(&tasklist_lock);
 
-	if (!retval && !(options & WNOHANG)) {
+notask:
+	retval = wo->notask_error;
+	if (!retval && !(wo->wo_flags & 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);
-		}
-	}
+	__set_current_state(TASK_RUNNING);
+	remove_wait_queue(&current->signal->wait_chldexit, &wo->child_wait);
 	return retval;
 }
 
 SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
 		infop, int, options, struct rusage __user *, ru)
 {
+	struct wait_opts wo;
 	struct pid *pid = NULL;
 	enum pid_type type;
 	long ret;
@@ -1677,7 +1686,37 @@ SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
 
 	if (type < PIDTYPE_MAX)
 		pid = find_get_pid(upid);
-	ret = do_wait(type, pid, options, infop, NULL, ru);
+
+	wo.wo_type	= type;
+	wo.wo_pid	= pid;
+	wo.wo_flags	= options;
+	wo.wo_info	= infop;
+	wo.wo_stat	= NULL;
+	wo.wo_rusage	= ru;
+	ret = do_wait(&wo);
+
+	if (ret > 0) {
+		ret = 0;
+	} else if (infop) {
+		/*
+		 * For a WNOHANG return, clear out all the fields
+		 * we would set so the user can easily tell the
+		 * difference.
+		 */
+		if (!ret)
+			ret = put_user(0, &infop->si_signo);
+		if (!ret)
+			ret = put_user(0, &infop->si_errno);
+		if (!ret)
+			ret = put_user(0, &infop->si_code);
+		if (!ret)
+			ret = put_user(0, &infop->si_pid);
+		if (!ret)
+			ret = put_user(0, &infop->si_uid);
+		if (!ret)
+			ret = put_user(0, &infop->si_status);
+	}
+
 	put_pid(pid);
 
 	/* avoid REGPARM breakage on x86: */
@@ -1688,6 +1727,7 @@ SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
 SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,
 		int, options, struct rusage __user *, ru)
 {
+	struct wait_opts wo;
 	struct pid *pid = NULL;
 	enum pid_type type;
 	long ret;
@@ -1709,7 +1749,13 @@ SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,
 		pid = find_get_pid(upid);
 	}
 
-	ret = do_wait(type, pid, options | WEXITED, NULL, stat_addr, ru);
+	wo.wo_type	= type;
+	wo.wo_pid	= pid;
+	wo.wo_flags	= options | WEXITED;
+	wo.wo_info	= NULL;
+	wo.wo_stat	= stat_addr;
+	wo.wo_rusage	= ru;
+	ret = do_wait(&wo);
 	put_pid(pid);
 
 	/* avoid REGPARM breakage on x86: */