Take fs_struct handling to new file (fs/fs_struct.c)
[safe/jmp/linux-2.6] / kernel / exit.c
index 7453356..ad83757 100644 (file)
 #include <linux/cn_proc.h>
 #include <linux/mutex.h>
 #include <linux/futex.h>
-#include <linux/compat.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 <linux/init_task.h>
+#include <trace/sched.h>
 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
 #include <asm/pgtable.h>
 #include <asm/mmu_context.h>
+#include "cred-internals.h"
+
+DEFINE_TRACE(sched_process_free);
+DEFINE_TRACE(sched_process_exit);
+DEFINE_TRACE(sched_process_wait);
 
 static void exit_mm(struct task_struct * tsk);
 
@@ -71,7 +78,7 @@ static void __unhash_process(struct task_struct *p)
                __get_cpu_var(process_counts)--;
        }
        list_del_rcu(&p->thread_group);
-       remove_parent(p);
+       list_del_init(&p->sibling);
 }
 
 /*
@@ -85,7 +92,6 @@ static void __exit_signal(struct task_struct *tsk)
        BUG_ON(!sig);
        BUG_ON(!atomic_read(&sig->count));
 
-       rcu_read_lock();
        sighand = rcu_dereference(tsk->sighand);
        spin_lock(&sighand->siglock);
 
@@ -112,15 +118,16 @@ 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, tsk->utime);
-               sig->stime = cputime_add(sig->stime, tsk->stime);
-               sig->gtime = cputime_add(sig->gtime, tsk->gtime);
+               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->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->sum_sched_runtime += tsk->se.sum_exec_runtime;
                sig = NULL; /* Marker for below. */
        }
@@ -136,32 +143,43 @@ static void __exit_signal(struct task_struct *tsk)
        tsk->signal = NULL;
        tsk->sighand = NULL;
        spin_unlock(&sighand->siglock);
-       rcu_read_unlock();
 
        __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)
 {
-       put_task_struct(container_of(rhp, struct task_struct, rcu));
+       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:
-       atomic_dec(&p->user->processes);
+       tracehook_prepare_release_task(p);
+       /* don't need to get the RCU readlock here - the process is dead and
+        * can't be modifying its own credentials */
+       atomic_dec(&__task_cred(p)->user->processes);
+
        proc_flush_task(p);
        write_lock_irq(&tasklist_lock);
-       ptrace_unlink(p);
-       BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children));
+       tracehook_finish_release_task(p);
        __exit_signal(p);
 
        /*
@@ -183,6 +201,13 @@ repeat:
                 * 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);
@@ -315,9 +340,8 @@ static void reparent_to_kthreadd(void)
 
        ptrace_unlink(current);
        /* Reparent to init */
-       remove_parent(current);
        current->real_parent = current->parent = kthreadd_task;
-       add_parent(current);
+       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;
@@ -327,12 +351,12 @@ static void reparent_to_kthreadd(void)
        /* 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));
+
+       atomic_inc(&init_cred.usage);
+       commit_creds(&init_cred);
        write_unlock_irq(&tasklist_lock);
-       switch_uid(INIT_USER);
 }
 
 void __set_special_pids(struct pid *pid)
@@ -405,7 +429,6 @@ EXPORT_SYMBOL(disallow_signal);
 void daemonize(const char *name, ...)
 {
        va_list args;
-       struct fs_struct *fs;
        sigset_t blocked;
 
        va_start(args, name);
@@ -422,7 +445,7 @@ void daemonize(const char *name, ...)
         * We don't want to have TIF_FREEZE set if the system-wide hibernation
         * or suspend transition begins right now.
         */
-       current->flags |= PF_NOFREEZE;
+       current->flags |= (PF_NOFREEZE | PF_KTHREAD);
 
        if (current->nsproxy != &init_nsproxy) {
                get_nsproxy(&init_nsproxy);
@@ -438,11 +461,7 @@ void daemonize(const char *name, ...)
 
        /* Become as one with the init task */
 
-       exit_fs(current);       /* current->fs->count--; */
-       fs = init_task.fs;
-       current->fs = fs;
-       atomic_inc(&fs->count);
-
+       daemonize_fs_struct();
        exit_files(current);
        current->files = init_task.files;
        atomic_inc(&current->files->count);
@@ -541,32 +560,6 @@ void exit_files(struct task_struct *tsk)
        }
 }
 
-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);
-               if (fs->altroot.dentry)
-                       path_put(&fs->altroot);
-               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
@@ -578,8 +571,6 @@ 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 (!mm)
-               return 0;
        if (atomic_read(&mm->mm_users) <= 1)
                return 0;
        if (mm->owner != p)
@@ -622,6 +613,12 @@ retry:
        } 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.
+        */
+       mm->owner = NULL;
        return;
 
 assign_new_owner:
@@ -642,7 +639,6 @@ assign_new_owner:
                put_task_struct(c);
                goto retry;
        }
-       cgroup_mm_owner_callbacks(mm->owner, c);
        mm->owner = c;
        task_unlock(c);
        put_task_struct(c);
@@ -656,26 +652,40 @@ assign_new_owner:
 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_waiters
+        * We must hold mmap_sem around checking core_state
         * and clearing tsk->mm.  The core-inducing thread
-        * will increment core_waiters for each thread in the
+        * will increment ->nr_threads for each thread in the
         * group with ->mm != NULL.
         */
        down_read(&mm->mmap_sem);
-       if (mm->core_waiters) {
+       core_state = mm->core_state;
+       if (core_state) {
+               struct core_thread self;
                up_read(&mm->mmap_sem);
-               down_write(&mm->mmap_sem);
-               if (!--mm->core_waiters)
-                       complete(mm->core_startup_done);
-               up_write(&mm->mmap_sem);
 
-               wait_for_completion(&mm->core_done);
+               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);
@@ -692,37 +702,97 @@ static void exit_mm(struct task_struct * tsk)
        mmput(mm);
 }
 
-static void
-reparent_thread(struct task_struct *p, struct task_struct *father, int traced)
+/*
+ * 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)
 {
-       if (p->pdeath_signal)
-               /* We already hold the tasklist_lock here.  */
-               group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
+       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;
+}
 
-       /* Move the child from its dying parent to the new one.  */
-       if (unlikely(traced)) {
-               /* Preserve ptrace links if someone else is tracing this child.  */
-               list_del_init(&p->ptrace_list);
-               if (ptrace_reparented(p))
-                       list_add(&p->ptrace_list, &p->real_parent->ptrace_children);
-       } else {
-               /* If this child is being traced, then we're the one tracing it
-                * anyway, so let go of it.
+/*
+ * 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.
                 */
-               p->ptrace = 0;
-               remove_parent(p);
-               p->parent = p->real_parent;
-               add_parent(p);
+               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_is_traced(p)) {
+               if (task_detached(p)) {
                        /*
-                        * If it was at a trace stop, turn it into
-                        * a normal stop since it's no longer being
-                        * traced.
+                        * Mark it as in the process of being reaped.
                         */
-                       ptrace_untrace(p);
+                       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.
@@ -737,7 +807,8 @@ reparent_thread(struct task_struct *p, struct task_struct *father, int traced)
        /* If we'd notified the old parent about this child's death,
         * also notify the new parent.
         */
-       if (!traced && p->exit_state == EXIT_ZOMBIE &&
+       if (!ptrace_reparented(p) &&
+           p->exit_state == EXIT_ZOMBIE &&
            !task_detached(p) && thread_group_empty(p))
                do_notify_parent(p, p->exit_signal);
 
@@ -751,75 +822,63 @@ reparent_thread(struct task_struct *p, struct task_struct *father, int traced)
  * the child reaper process (ie "init") in our pid
  * space.
  */
-static void forget_original_parent(struct task_struct *father)
+static struct task_struct *find_new_reaper(struct task_struct *father)
 {
-       struct task_struct *p, *n, *reaper = father;
-       struct list_head ptrace_dead;
-
-       INIT_LIST_HEAD(&ptrace_dead);
-
-       write_lock_irq(&tasklist_lock);
-
-       do {
-               reaper = next_thread(reaper);
-               if (reaper == father) {
-                       reaper = task_child_reaper(father);
-                       break;
-               }
-       } while (reaper->flags & PF_EXITING);
-
-       /*
-        * There are only two places where our children can be:
-        *
-        * - in our child list
-        * - in our ptraced child list
-        *
-        * Search them and reparent children.
-        */
-       list_for_each_entry_safe(p, n, &father->children, sibling) {
-               int ptrace;
-
-               ptrace = p->ptrace;
+       struct pid_namespace *pid_ns = task_active_pid_ns(father);
+       struct task_struct *thread;
 
-               /* if father isn't the real parent, then ptrace must be enabled */
-               BUG_ON(father != p->real_parent && !ptrace);
+       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 (father == p->real_parent) {
-                       /* reparent with a reaper, real father it's us */
-                       p->real_parent = reaper;
-                       reparent_thread(p, father, 0);
-               } else {
-                       /* reparent ptraced task to its real parent */
-                       __ptrace_unlink (p);
-                       if (p->exit_state == EXIT_ZOMBIE && !task_detached(p) &&
-                           thread_group_empty(p))
-                               do_notify_parent(p, p->exit_signal);
-               }
+       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);
                /*
-                * if the ptraced child is a detached zombie we must collect
-                * it before we exit, or it will remain zombie forever since
-                * we prevented it from self-reap itself while it was being
-                * traced by us, to be able to see it in wait4.
+                * 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.
                 */
-               if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && task_detached(p)))
-                       list_add(&p->ptrace_list, &ptrace_dead);
+               pid_ns->child_reaper = init_pid_ns.child_reaper;
        }
 
-       list_for_each_entry_safe(p, n, &father->ptrace_children, ptrace_list) {
+       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;
-               reparent_thread(p, father, 1);
+               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));
-       BUG_ON(!list_empty(&father->ptrace_children));
-
-       list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_list) {
-               list_del_init(&p->ptrace_list);
-               release_task(p);
-       }
 
+       ptrace_exit_finish(father, &ptrace_dead);
 }
 
 /*
@@ -828,7 +887,8 @@ static void forget_original_parent(struct task_struct *father)
  */
 static void exit_notify(struct task_struct *tsk, int group_dead)
 {
-       int state;
+       int signal;
+       void *cookie;
 
        /*
         * This does two things:
@@ -865,33 +925,24 @@ static void exit_notify(struct task_struct *tsk, int group_dead)
            !capable(CAP_KILL))
                tsk->exit_signal = SIGCHLD;
 
-       /* If something other than our normal parent is ptracing us, then
-        * send it a SIGCHLD instead of honoring exit_signal.  exit_signal
-        * only has special meaning to our real parent.
-        */
-       if (!task_detached(tsk) && thread_group_empty(tsk)) {
-               int signal = ptrace_reparented(tsk) ?
-                               SIGCHLD : tsk->exit_signal;
-               do_notify_parent(tsk, signal);
-       } else if (tsk->ptrace) {
-               do_notify_parent(tsk, SIGCHLD);
-       }
+       signal = tracehook_notify_death(tsk, &cookie, group_dead);
+       if (signal >= 0)
+               signal = do_notify_parent(tsk, signal);
 
-       state = EXIT_ZOMBIE;
-       if (task_detached(tsk) && likely(!tsk->ptrace))
-               state = EXIT_DEAD;
-       tsk->exit_state = state;
+       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->notify_count < 0 &&
-           tsk->signal->group_exit_task)
+           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 (state == EXIT_DEAD)
+       if (signal == DEATH_REAP)
                release_task(tsk);
 }
 
@@ -900,12 +951,9 @@ 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);
+       free = stack_not_used(current);
 
        if (free >= lowest_to_date)
                return;
@@ -923,39 +971,6 @@ static void check_stack_usage(void)
 static inline void check_stack_usage(void) {}
 #endif
 
-static inline void exit_child_reaper(struct task_struct *tsk)
-{
-       if (likely(tsk->group_leader != task_child_reaper(tsk)))
-               return;
-
-       if (tsk->nsproxy->pid_ns == &init_pid_ns)
-               panic("Attempted to kill init!");
-
-       /*
-        * @tsk is the last thread in the 'cgroup-init' and is exiting.
-        * Terminate all remaining processes in the namespace and reap them
-        * before exiting @tsk.
-        *
-        * Note that @tsk (last thread of cgroup-init) may not necessarily
-        * be the child-reaper (i.e main thread of cgroup-init) of the
-        * namespace i.e the child_reaper may have already exited.
-        *
-        * Even after a child_reaper exits, we let it inherit orphaned children,
-        * because, pid_ns->child_reaper remains valid as long as there is
-        * at least one living sub-thread in the cgroup init.
-
-        * This living sub-thread of the cgroup-init will be notified when
-        * a child inherited by the 'child-reaper' exits (do_notify_parent()
-        * uses __group_send_sig_info()). Further, when reaping child processes,
-        * do_wait() iterates over children of all living sub threads.
-
-        * i.e even though 'child_reaper' thread is listed as the parent of the
-        * orphaned children, any living sub-thread in the cgroup-init can
-        * perform the role of the child_reaper.
-        */
-       zap_pid_ns_processes(tsk->nsproxy->pid_ns);
-}
-
 NORET_TYPE void do_exit(long code)
 {
        struct task_struct *tsk = current;
@@ -970,10 +985,7 @@ NORET_TYPE void do_exit(long code)
        if (unlikely(!tsk->pid))
                panic("Attempted to kill the idle task!");
 
-       if (unlikely(current->ptrace & PT_TRACE_EXIT)) {
-               current->ptrace_message = code;
-               ptrace_notify((PTRACE_EVENT_EXIT << 8) | SIGTRAP);
-       }
+       tracehook_report_exit(&code);
 
        /*
         * We're taking recursive faults here in do_exit. Safest is to just
@@ -992,8 +1004,6 @@ NORET_TYPE void do_exit(long code)
                 * 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();
        }
@@ -1012,25 +1022,13 @@ NORET_TYPE void do_exit(long code)
                                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) {
-               exit_child_reaper(tsk);
                hrtimer_cancel(&tsk->signal->real_timer);
                exit_itimers(tsk->signal);
        }
        acct_collect(code, group_dead);
-#ifdef CONFIG_FUTEX
-       if (unlikely(tsk->robust_list))
-               exit_robust_list(tsk);
-#ifdef CONFIG_COMPAT
-       if (unlikely(tsk->compat_robust_list))
-               compat_exit_robust_list(tsk);
-#endif
-#endif
        if (group_dead)
                tty_audit_exit();
        if (unlikely(tsk->audit_context))
@@ -1043,13 +1041,14 @@ NORET_TYPE void do_exit(long code)
 
        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);
@@ -1094,7 +1093,6 @@ NORET_TYPE void do_exit(long code)
        preempt_disable();
        /* causes final put_task_struct in finish_task_switch(). */
        tsk->state = TASK_DEAD;
-
        schedule();
        BUG();
        /* Avoid "noreturn function does return".  */
@@ -1114,7 +1112,7 @@ NORET_TYPE void complete_and_exit(struct completion *comp, long code)
 
 EXPORT_SYMBOL(complete_and_exit);
 
-asmlinkage long sys_exit(int error_code)
+SYSCALL_DEFINE1(exit, int, error_code)
 {
        do_exit((error_code&0xff)<<8);
 }
@@ -1155,9 +1153,11 @@ do_group_exit(int exit_code)
  * wait4()-ing process will get the correct exit code - even if this
  * thread is not the thread group leader.
  */
-asmlinkage void sys_exit_group(int error_code)
+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)
@@ -1180,13 +1180,6 @@ static int eligible_child(enum pid_type type, struct pid *pid, int options,
                        return 0;
        }
 
-       /*
-        * Do not consider detached threads that are
-        * not ptraced:
-        */
-       if (task_detached(p) && !p->ptrace)
-               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:
@@ -1197,14 +1190,10 @@ static int eligible_child(enum pid_type type, struct pid *pid, int options,
                return 0;
 
        err = security_task_wait(p);
-       if (likely(!err))
-               return 1;
+       if (err)
+               return err;
 
-       if (type != PIDTYPE_PID)
-               return 0;
-       /* This child was explicitly requested, abort */
-       read_unlock(&tasklist_lock);
-       return err;
+       return 1;
 }
 
 static int wait_noreap_copyout(struct task_struct *p, pid_t pid, uid_t uid,
@@ -1245,12 +1234,12 @@ static int wait_task_zombie(struct task_struct *p, int options,
        unsigned long state;
        int retval, status, traced;
        pid_t pid = task_pid_vnr(p);
+       uid_t uid = __task_cred(p)->uid;
 
        if (!likely(options & WEXITED))
                return 0;
 
        if (unlikely(options & WNOWAIT)) {
-               uid_t uid = p->uid;
                int exit_code = p->exit_code;
                int why, status;
 
@@ -1282,6 +1271,7 @@ static int wait_task_zombie(struct task_struct *p, int options,
        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
@@ -1297,20 +1287,23 @@ static int wait_task_zombie(struct task_struct *p, int options,
                 * 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.
                 */
+               thread_group_cputime(p, &cputime);
                spin_lock_irq(&p->parent->sighand->siglock);
                psig = p->parent->signal;
                sig = p->signal;
                psig->cutime =
                        cputime_add(psig->cutime,
-                       cputime_add(p->utime,
-                       cputime_add(sig->utime,
-                                   sig->cutime)));
+                       cputime_add(cputime.utime,
+                                   sig->cutime));
                psig->cstime =
                        cputime_add(psig->cstime,
-                       cputime_add(p->stime,
-                       cputime_add(sig->stime,
-                                   sig->cstime)));
+                       cputime_add(cputime.stime,
+                                   sig->cstime));
                psig->cgtime =
                        cputime_add(psig->cgtime,
                        cputime_add(p->gtime,
@@ -1330,6 +1323,8 @@ static int wait_task_zombie(struct task_struct *p, int options,
                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);
        }
 
@@ -1365,7 +1360,7 @@ static int wait_task_zombie(struct task_struct *p, int options,
        if (!retval && infop)
                retval = put_user(pid, &infop->si_pid);
        if (!retval && infop)
-               retval = put_user(p->uid, &infop->si_uid);
+               retval = put_user(uid, &infop->si_uid);
        if (!retval)
                retval = pid;
 
@@ -1399,7 +1394,7 @@ static int wait_task_zombie(struct task_struct *p, int options,
  * 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(struct task_struct *p,
+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)
 {
@@ -1407,7 +1402,7 @@ static int wait_task_stopped(struct task_struct *p,
        uid_t uid = 0; /* unneeded, required by compiler */
        pid_t pid;
 
-       if (!(p->ptrace & PT_PTRACED) && !(options & WUNTRACED))
+       if (!(options & WUNTRACED))
                return 0;
 
        exit_code = 0;
@@ -1416,7 +1411,7 @@ static int wait_task_stopped(struct task_struct *p,
        if (unlikely(!task_is_stopped_or_traced(p)))
                goto unlock_sig;
 
-       if (!(p->ptrace & PT_PTRACED) && p->signal->group_stop_count > 0)
+       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.
@@ -1430,7 +1425,8 @@ static int wait_task_stopped(struct task_struct *p,
        if (!unlikely(options & WNOWAIT))
                p->exit_code = 0;
 
-       uid = p->uid;
+       /* don't need the RCU readlock here as we're holding a spinlock */
+       uid = __task_cred(p)->uid;
 unlock_sig:
        spin_unlock_irq(&p->sighand->siglock);
        if (!exit_code)
@@ -1445,7 +1441,7 @@ unlock_sig:
         */
        get_task_struct(p);
        pid = task_pid_vnr(p);
-       why = (p->ptrace & PT_PTRACED) ? CLD_TRAPPED : CLD_STOPPED;
+       why = ptrace ? CLD_TRAPPED : CLD_STOPPED;
        read_unlock(&tasklist_lock);
 
        if (unlikely(options & WNOWAIT))
@@ -1504,10 +1500,10 @@ static int wait_task_continued(struct task_struct *p, int options,
        }
        if (!unlikely(options & WNOWAIT))
                p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
+       uid = __task_cred(p)->uid;
        spin_unlock_irq(&p->sighand->siglock);
 
        pid = task_pid_vnr(p);
-       uid = p->uid;
        get_task_struct(p);
        read_unlock(&tasklist_lock);
 
@@ -1534,18 +1530,40 @@ static int wait_task_continued(struct task_struct *p, int options,
  * -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 still -ECHILD.
+ * 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,
+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 <= 0)
+       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;
 
@@ -1562,7 +1580,8 @@ static int wait_consider_task(struct task_struct *parent,
        *notask_error = 0;
 
        if (task_is_stopped_or_traced(p))
-               return wait_task_stopped(p, options, infop, stat_addr, ru);
+               return wait_task_stopped(ptrace, p, options,
+                                        infop, stat_addr, ru);
 
        return wait_task_continued(p, options, infop, stat_addr, ru);
 }
@@ -1573,7 +1592,8 @@ static int wait_consider_task(struct task_struct *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 there were any eligible children, or still -ECHILD.
+ * *@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,
@@ -1583,11 +1603,16 @@ static int do_wait_thread(struct task_struct *tsk, int *notask_error,
        struct task_struct *p;
 
        list_for_each_entry(p, &tsk->children, sibling) {
-               int ret = wait_consider_task(tsk, p, notask_error,
-                                            type, pid, options,
-                                            infop, stat_addr, ru);
-               if (ret)
-                       return ret;
+               /*
+                * 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;
@@ -1601,21 +1626,16 @@ static int ptrace_do_wait(struct task_struct *tsk, int *notask_error,
        struct task_struct *p;
 
        /*
-        * If we never saw an eligile child, check for children stolen by
-        * ptrace.  We don't leave -ECHILD in *@notask_error if there are any,
-        * because we will eventually be allowed to wait for them again.
+        * Traditionally we see ptrace'd stopped tasks regardless of options.
         */
-       if (!*notask_error)
-               return 0;
+       options |= WUNTRACED;
 
-       list_for_each_entry(p, &tsk->ptrace_children, ptrace_list) {
-               int ret = eligible_child(type, pid, options, p);
-               if (unlikely(ret < 0))
+       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;
-               if (ret) {
-                       *notask_error = 0;
-                       return 0;
-               }
        }
 
        return 0;
@@ -1629,6 +1649,8 @@ static long do_wait(enum pid_type type, struct pid *pid, int options,
        struct task_struct *tsk;
        int retval;
 
+       trace_sched_process_wait(pid);
+
        add_wait_queue(&current->signal->wait_chldexit,&wait);
 repeat:
        /*
@@ -1703,9 +1725,8 @@ end:
        return retval;
 }
 
-asmlinkage long sys_waitid(int which, pid_t upid,
-                          struct siginfo __user *infop, int options,
-                          struct rusage __user *ru)
+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;
@@ -1744,8 +1765,8 @@ asmlinkage long sys_waitid(int which, pid_t upid,
        return ret;
 }
 
-asmlinkage long sys_wait4(pid_t upid, int __user *stat_addr,
-                         int options, struct rusage __user *ru)
+SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,
+               int, options, struct rusage __user *, ru)
 {
        struct pid *pid = NULL;
        enum pid_type type;
@@ -1782,7 +1803,7 @@ asmlinkage long sys_wait4(pid_t upid, int __user *stat_addr,
  * sys_waitpid() remains for compatibility. waitpid() should be
  * implemented by calling sys_wait4() from libc.a.
  */
-asmlinkage long sys_waitpid(pid_t pid, int __user *stat_addr, int options)
+SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options)
 {
        return sys_wait4(pid, stat_addr, options, NULL);
 }