Merge branch 'master' into next
[linux-3.10.git] / kernel / exit.c
index d2e8239..036e8d7 100644 (file)
@@ -46,6 +46,7 @@
 #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/sched.h>
 
@@ -61,11 +62,6 @@ DEFINE_TRACE(sched_process_wait);
 
 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--;
@@ -362,16 +358,12 @@ static void reparent_to_kthreadd(void)
 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)
@@ -429,7 +421,6 @@ EXPORT_SYMBOL(disallow_signal);
 void daemonize(const char *name, ...)
 {
        va_list args;
-       struct fs_struct *fs;
        sigset_t blocked;
 
        va_start(args, name);
@@ -462,11 +453,7 @@ 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);
@@ -565,30 +552,6 @@ 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);
-               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
@@ -732,119 +695,6 @@ 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.
- */
-static void ptrace_exit(struct task_struct *parent, struct list_head *dead)
-{
-       struct task_struct *p, *n;
-       int ign = -1;
-
-       list_for_each_entry_safe(p, n, &parent->ptraced, ptrace_entry) {
-               __ptrace_unlink(p);
-
-               if (p->exit_state != EXIT_ZOMBIE)
-                       continue;
-
-               /*
-                * If it's a zombie, our attachedness prevented normal
-                * parent notification or self-reaping.  Do notification
-                * now if it would have happened earlier.  If it should
-                * reap itself, add it to the @dead list.  We can't call
-                * release_task() here because we already hold tasklist_lock.
-                *
-                * If it's our own child, there is no notification to do.
-                * But if our normal children self-reap, then this child
-                * was prevented by ptrace and we must reap it now.
-                */
-               if (!task_detached(p) && thread_group_empty(p)) {
-                       if (!same_thread_group(p->real_parent, parent))
-                               do_notify_parent(p, p->exit_signal);
-                       else {
-                               if (ign < 0)
-                                       ign = ignoring_children(parent);
-                               if (ign)
-                                       p->exit_signal = -1;
-                       }
-               }
-
-               if (task_detached(p)) {
-                       /*
-                        * Mark it as in the process of being reaped.
-                        */
-                       p->exit_state = EXIT_DEAD;
-                       list_add(&p->ptrace_entry, dead);
-               }
-       }
-}
-
-/*
- * Finish up exit-time ptrace cleanup.
- *
- * Called without locks.
- */
-static void ptrace_exit_finish(struct task_struct *parent,
-                              struct list_head *dead)
-{
-       struct task_struct *p, *n;
-
-       BUG_ON(!list_empty(&parent->ptraced));
-
-       list_for_each_entry_safe(p, n, dead, ptrace_entry) {
-               list_del_init(&p->ptrace_entry);
-               release_task(p);
-       }
-}
-
-static void reparent_thread(struct task_struct *p, struct task_struct *father)
-{
-       if (p->pdeath_signal)
-               /* We already hold the tasklist_lock here.  */
-               group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
-
-       list_move_tail(&p->sibling, &p->real_parent->children);
-
-       /* If this is a threaded reparent there is no need to
-        * notify anyone anything has happened.
-        */
-       if (same_thread_group(p->real_parent, father))
-               return;
-
-       /* We don't want people slaying init.  */
-       if (!task_detached(p))
-               p->exit_signal = SIGCHLD;
-
-       /* If we'd notified the old parent about this child's death,
-        * also notify the new parent.
-        */
-       if (!ptrace_reparented(p) &&
-           p->exit_state == EXIT_ZOMBIE &&
-           !task_detached(p) && thread_group_empty(p))
-               do_notify_parent(p, p->exit_signal);
-
-       kill_orphaned_pgrp(p, father);
-}
-
-/*
  * When we die, we re-parent all our children.
  * Try to give them to another thread in our thread
  * group, and if no such member exists, give it to
@@ -883,17 +733,51 @@ static struct task_struct *find_new_reaper(struct task_struct *father)
        return pid_ns->child_reaper;
 }
 
+/*
+* Any that need to be release_task'd are put on the @dead list.
+ */
+static void reparent_thread(struct task_struct *father, struct task_struct *p,
+                               struct list_head *dead)
+{
+       if (p->pdeath_signal)
+               group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
+
+       list_move_tail(&p->sibling, &p->real_parent->children);
+
+       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.  */
+       p->exit_signal = SIGCHLD;
+
+       /* 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);
+}
+
 static void forget_original_parent(struct task_struct *father)
 {
        struct task_struct *p, *n, *reaper;
-       LIST_HEAD(ptrace_dead);
+       LIST_HEAD(dead_children);
+
+       exit_ptrace(father);
 
        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;
@@ -901,13 +785,16 @@ 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);
+       }
 }
 
 /*
@@ -950,8 +837,7 @@ 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;
 
        signal = tracehook_notify_death(tsk, &cookie, group_dead);
@@ -1037,6 +923,8 @@ NORET_TYPE void do_exit(long code)
                schedule();
        }
 
+       exit_irq_thread();
+
        exit_signals(tsk);  /* sets PF_EXITING */
        /*
         * tsk->flags are checked in the futex code to protect against
@@ -1417,6 +1305,18 @@ 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
@@ -1427,7 +1327,7 @@ 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;
 
@@ -1437,22 +1337,16 @@ 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;
 
        /* don't need the RCU readlock here as we're holding a spinlock */
        uid = __task_cred(p)->uid;
@@ -1609,7 +1503,7 @@ 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);
 
@@ -1813,7 +1707,7 @@ SYSCALL_DEFINE4(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);