]> nv-tegra.nvidia Code Review - linux-3.10.git/blobdiff - kernel/exit.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris...
[linux-3.10.git] / kernel / exit.c
index f7fa21dbced4b17d86347582a410e97c2f5c105c..51d1fe3fb7ad5b60666c7f229d6bacd8942479e9 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/fs_struct.h>
+#include <linux/init_task.h>
+#include <trace/events/sched.h>
 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
 #include <asm/pgtable.h>
 #include <asm/mmu_context.h>
+#include "cred-internals.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--;
@@ -111,15 +110,16 @@ 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. */
        }
@@ -141,36 +141,37 @@ static void __exit_signal(struct task_struct *tsk)
        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);
 
-/*
- * Do final ptrace-related cleanup of a zombie being reaped.
- *
- * Called with write_lock(&tasklist_lock) held.
- */
-static void ptrace_release_task(struct task_struct *p)
-{
-       BUG_ON(!list_empty(&p->ptraced));
-       ptrace_unlink(p);
-       BUG_ON(!list_empty(&p->ptrace_entry));
+       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_release_task(p);
+       tracehook_finish_release_task(p);
        __exit_signal(p);
 
        /*
@@ -192,6 +193,13 @@ 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);
@@ -335,27 +343,23 @@ 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)
 {
        struct task_struct *curr = current->group_leader;
-       pid_t nr = pid_nr(pid);
 
-       if (task_session(curr) != pid) {
+       if (task_session(curr) != pid)
                change_pid(curr, PIDTYPE_SID, pid);
-               set_task_session(curr, nr);
-       }
-       if (task_pgrp(curr) != pid) {
+
+       if (task_pgrp(curr) != pid)
                change_pid(curr, PIDTYPE_PGID, pid);
-               set_task_pgrp(curr, nr);
-       }
 }
 
 static void set_special_pids(struct pid *pid)
@@ -413,7 +417,6 @@ EXPORT_SYMBOL(disallow_signal);
 void daemonize(const char *name, ...)
 {
        va_list args;
-       struct fs_struct *fs;
        sigset_t blocked;
 
        va_start(args, name);
@@ -446,11 +449,7 @@ 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);
@@ -549,32 +548,6 @@ 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
@@ -586,8 +559,6 @@ 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)
@@ -630,6 +601,12 @@ 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:
@@ -650,7 +627,6 @@ 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);
@@ -664,26 +640,40 @@ 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_state->startup);
-               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);
@@ -701,144 +691,89 @@ static void exit_mm(struct task_struct * tsk)
 }
 
 /*
- * 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.
+ * 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 void ptrace_exit(struct task_struct *parent, struct list_head *dead)
+static struct task_struct *find_new_reaper(struct task_struct *father)
 {
-       struct task_struct *p, *n;
-       int ign = -1;
-
-       list_for_each_entry_safe(p, n, &parent->ptraced, ptrace_entry) {
-               __ptrace_unlink(p);
+       struct pid_namespace *pid_ns = task_active_pid_ns(father);
+       struct task_struct *thread;
 
-               if (p->exit_state != EXIT_ZOMBIE)
+       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);
                /*
-                * 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.
+                * 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 (!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);
-               }
+               pid_ns->child_reaper = init_pid_ns.child_reaper;
        }
+
+       return pid_ns->child_reaper;
 }
 
 /*
- * Finish up exit-time ptrace cleanup.
- *
- * Called without locks.
+* Any that need to be release_task'd are put on the @dead list.
  */
-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)
+static void reparent_thread(struct task_struct *father, struct task_struct *p,
+                               struct list_head *dead)
 {
        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
+       if (task_detached(p))
+               return;
+       /*
+        * 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;
+       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))
+       /* If it has exited notify the new parent about this child's death. */
+       if (!p->ptrace &&
+           p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) {
                do_notify_parent(p, p->exit_signal);
+               if (task_detached(p)) {
+                       p->exit_state = EXIT_DEAD;
+                       list_move_tail(&p->sibling, dead);
+               }
+       }
 
        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 void forget_original_parent(struct task_struct *father)
 {
-       struct task_struct *p, *n, *reaper = father;
-       LIST_HEAD(ptrace_dead);
+       struct task_struct *p, *n, *reaper;
+       LIST_HEAD(dead_children);
 
-       write_lock_irq(&tasklist_lock);
+       exit_ptrace(father);
 
-       /*
-        * First clean up ptrace if we were using it.
-        */
-       ptrace_exit(father, &ptrace_dead);
-
-       do {
-               reaper = next_thread(reaper);
-               if (reaper == father) {
-                       reaper = task_child_reaper(father);
-                       break;
-               }
-       } while (reaper->flags & PF_EXITING);
+       write_lock_irq(&tasklist_lock);
+       reaper = find_new_reaper(father);
 
        list_for_each_entry_safe(p, n, &father->children, sibling) {
                p->real_parent = reaper;
@@ -846,13 +781,16 @@ static void forget_original_parent(struct task_struct *father)
                        BUG_ON(p->ptrace);
                        p->parent = p->real_parent;
                }
-               reparent_thread(p, father);
+               reparent_thread(father, p, &dead_children);
        }
-
        write_unlock_irq(&tasklist_lock);
+
        BUG_ON(!list_empty(&father->children));
 
-       ptrace_exit_finish(father, &ptrace_dead);
+       list_for_each_entry_safe(p, n, &dead_children, sibling) {
+               list_del_init(&p->sibling);
+               release_task(p);
+       }
 }
 
 /*
@@ -861,7 +799,8 @@ 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:
@@ -894,37 +833,27 @@ static void exit_notify(struct task_struct *tsk, int group_dead)
         */
        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->self_exec_id != tsk->parent_exec_id))
                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);
 }
 
@@ -933,12 +862,9 @@ 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;
@@ -956,39 +882,6 @@ 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;
@@ -1003,10 +896,7 @@ 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
@@ -1025,12 +915,12 @@ 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();
        }
 
+       exit_irq_thread();
+
        exit_signals(tsk);  /* sets PF_EXITING */
        /*
         * tsk->flags are checked in the futex code to protect against
@@ -1045,25 +935,13 @@ 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))
@@ -1076,13 +954,14 @@ 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);
@@ -1127,7 +1006,6 @@ 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".  */
@@ -1147,7 +1025,7 @@ 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);
 }
@@ -1188,9 +1066,11 @@ 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)
@@ -1267,12 +1147,12 @@ 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;
 
@@ -1304,6 +1184,7 @@ 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
@@ -1319,20 +1200,23 @@ 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,
@@ -1352,6 +1236,8 @@ 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);
        }
 
@@ -1387,7 +1273,7 @@ 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;
 
@@ -1415,6 +1301,18 @@ static int wait_task_zombie(struct task_struct *p, int options,
        return retval;
 }
 
+static int *task_stopped_code(struct task_struct *p, bool ptrace)
+{
+       if (ptrace) {
+               if (task_is_stopped_or_traced(p))
+                       return &p->exit_code;
+       } else {
+               if (p->signal->flags & SIGNAL_STOP_STOPPED)
+                       return &p->signal->group_exit_code;
+       }
+       return NULL;
+}
+
 /*
  * 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
@@ -1425,7 +1323,7 @@ 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;
+       int retval, exit_code, *p_code, why;
        uid_t uid = 0; /* unneeded, required by compiler */
        pid_t pid;
 
@@ -1435,24 +1333,19 @@ static int wait_task_stopped(int ptrace, struct task_struct *p,
        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.
-                */
+       p_code = task_stopped_code(p, ptrace);
+       if (unlikely(!p_code))
                goto unlock_sig;
 
-       exit_code = p->exit_code;
+       exit_code = *p_code;
        if (!exit_code)
                goto unlock_sig;
 
        if (!unlikely(options & WNOWAIT))
-               p->exit_code = 0;
+               *p_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)
@@ -1526,10 +1419,10 @@ 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);
 
@@ -1579,6 +1472,7 @@ static int wait_consider_task(struct task_struct *parent, int ptrace,
                 */
                if (*notask_error)
                        *notask_error = ret;
+               return 0;
        }
 
        if (likely(!ptrace) && unlikely(p->ptrace)) {
@@ -1605,7 +1499,7 @@ static int wait_consider_task(struct task_struct *parent, int ptrace,
         */
        *notask_error = 0;
 
-       if (task_is_stopped_or_traced(p))
+       if (task_stopped_code(p, ptrace))
                return wait_task_stopped(ptrace, p, options,
                                         infop, stat_addr, ru);
 
@@ -1675,6 +1569,8 @@ 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:
        /*
@@ -1749,9 +1645,8 @@ 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;
@@ -1790,8 +1685,8 @@ 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;
@@ -1808,7 +1703,7 @@ asmlinkage long sys_wait4(pid_t upid, int __user *stat_addr,
                pid = find_get_pid(-upid);
        } else if (upid == 0) {
                type = PIDTYPE_PGID;
-               pid = get_pid(task_pgrp(current));
+               pid = get_task_pid(current, PIDTYPE_PGID);
        } else /* upid > 0 */ {
                type = PIDTYPE_PID;
                pid = find_get_pid(upid);
@@ -1828,7 +1723,7 @@ 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);
 }