X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fexit.c;h=073005b1cfb2b072245f64edd313fe8c466c6992;hb=6fd36390117f7844ad147377878ddb52088f583a;hp=8d289bfc13d1c3f87c7f819595f05ebbd58481d6;hpb=937949d9edbf4049bd41af6c9f92c26280584564;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/exit.c b/kernel/exit.c index 8d289bf..073005b 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -7,13 +7,12 @@ #include #include #include -#include #include #include #include #include #include -#include +#include #include #include #include @@ -22,14 +21,17 @@ #include #include #include +#include #include #include #include #include +#include #include #include #include -#include +#include +#include #include #include #include @@ -41,15 +43,13 @@ #include /* for audit_free() */ #include #include +#include #include #include #include #include -extern void sem_exit (void); -extern struct task_struct *child_reaper; - static void exit_mm(struct task_struct * tsk); static void __unhash_process(struct task_struct *p) @@ -90,10 +90,9 @@ static void __exit_signal(struct task_struct *tsk) * If there is any task waiting for the group exit * then notify it: */ - if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count) { + if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count) wake_up_process(sig->group_exit_task); - sig->group_exit_task = NULL; - } + if (tsk == sig->curr_target) sig->curr_target = next_thread(tsk); /* @@ -108,11 +107,14 @@ static void __exit_signal(struct task_struct *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; sig->nivcsw += tsk->nivcsw; - sig->sched_time += tsk->sched_time; + sig->inblock += task_io_get_inblock(tsk); + sig->oublock += task_io_get_oublock(tsk); + sig->sum_sched_runtime += tsk->se.sum_exec_runtime; sig = NULL; /* Marker for below. */ } @@ -144,6 +146,7 @@ void release_task(struct task_struct * p) int zap_leader; repeat: atomic_dec(&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)); @@ -170,9 +173,7 @@ repeat: zap_leader = (leader->exit_signal == -1); } - sched_exit(p); write_unlock_irq(&tasklist_lock); - proc_flush_task(p); release_thread(p); call_rcu(&p->rcu, delayed_put_task_struct); @@ -185,25 +186,20 @@ repeat: * This checks not only the pgrp, but falls back on the pid if no * satisfactory pgrp is found. I dunno - gdb doesn't work correctly * without this... + * + * The caller must hold rcu lock or the tasklist lock. */ -int session_of_pgrp(int pgrp) +struct pid *session_of_pgrp(struct pid *pgrp) { struct task_struct *p; - int sid = -1; + struct pid *sid = NULL; + + p = pid_task(pgrp, PIDTYPE_PGID); + if (p == NULL) + p = pid_task(pgrp, PIDTYPE_PID); + if (p != NULL) + sid = task_session(p); - read_lock(&tasklist_lock); - do_each_task_pid(pgrp, PIDTYPE_PGID, p) { - if (process_session(p) > 0) { - sid = process_session(p); - goto out; - } - } while_each_task_pid(pgrp, PIDTYPE_PGID, p); - p = find_task_by_pid(pgrp); - if (p) - sid = process_session(p); -out: - read_unlock(&tasklist_lock); - return sid; } @@ -215,77 +211,106 @@ out: * * "I ask you, have you ever known what it is to be an orphan?" */ -static int will_become_orphaned_pgrp(int pgrp, struct task_struct *ignored_task) +static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task) { struct task_struct *p; - int ret = 1; - do_each_task_pid(pgrp, PIDTYPE_PGID, p) { - if (p == ignored_task - || p->exit_state - || is_init(p->real_parent)) + do_each_pid_task(pgrp, PIDTYPE_PGID, p) { + if ((p == ignored_task) || + (p->exit_state && thread_group_empty(p)) || + is_global_init(p->real_parent)) continue; - if (process_group(p->real_parent) != pgrp && - process_session(p->real_parent) == process_session(p)) { - ret = 0; - break; - } - } while_each_task_pid(pgrp, PIDTYPE_PGID, p); - return ret; /* (sighing) "Often!" */ + + if (task_pgrp(p->real_parent) != pgrp && + task_session(p->real_parent) == task_session(p)) + return 0; + } while_each_pid_task(pgrp, PIDTYPE_PGID, p); + + return 1; } -int is_orphaned_pgrp(int pgrp) +int is_current_pgrp_orphaned(void) { int retval; read_lock(&tasklist_lock); - retval = will_become_orphaned_pgrp(pgrp, NULL); + retval = will_become_orphaned_pgrp(task_pgrp(current), NULL); read_unlock(&tasklist_lock); return retval; } -static int has_stopped_jobs(int pgrp) +static int has_stopped_jobs(struct pid *pgrp) { int retval = 0; struct task_struct *p; - do_each_task_pid(pgrp, PIDTYPE_PGID, p) { - if (p->state != TASK_STOPPED) + do_each_pid_task(pgrp, PIDTYPE_PGID, p) { + if (!task_is_stopped(p)) continue; retval = 1; break; - } while_each_task_pid(pgrp, PIDTYPE_PGID, p); + } while_each_pid_task(pgrp, PIDTYPE_PGID, p); return retval; } +/* + * Check to see if any process groups have become orphaned as + * a result of our exiting, and if they have any stopped jobs, + * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) + */ +static void +kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent) +{ + struct pid *pgrp = task_pgrp(tsk); + struct task_struct *ignored_task = tsk; + + if (!parent) + /* exit: our father is in a different pgrp than + * we are and we were the only connection outside. + */ + parent = tsk->real_parent; + else + /* reparent: our child is in a different pgrp than + * we are, and it was the only connection outside. + */ + ignored_task = NULL; + + if (task_pgrp(parent) != pgrp && + task_session(parent) == task_session(tsk) && + will_become_orphaned_pgrp(pgrp, ignored_task) && + has_stopped_jobs(pgrp)) { + __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp); + __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp); + } +} + /** - * reparent_to_init - Reparent the calling kernel thread to the init task. + * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd * * If a kernel thread is launched as a result of a system call, or if - * it ever exits, it should generally reparent itself to init so that - * it is correctly cleaned up on exit. + * it ever exits, it should generally reparent itself to kthreadd so it + * isn't in the way of other processes and is correctly cleaned up on exit. * * The various task state such as scheduling policy and priority may have * been inherited from a user process, so we reset them to sane values here. * - * NOTE that reparent_to_init() gives the caller full capabilities. + * NOTE that reparent_to_kthreadd() gives the caller full capabilities. */ -static void reparent_to_init(void) +static void reparent_to_kthreadd(void) { write_lock_irq(&tasklist_lock); ptrace_unlink(current); /* Reparent to init */ remove_parent(current); - current->parent = child_reaper; - current->real_parent = child_reaper; + current->real_parent = current->parent = kthreadd_task; add_parent(current); /* Set the exit signal to SIGCHLD so we signal init on exit */ current->exit_signal = SIGCHLD; - if (!has_rt_policy(current) && (task_nice(current) < 0)) + if (task_nice(current) < 0) set_user_nice(current, 0); /* cpus_allowed? */ /* rt_priority? */ @@ -298,26 +323,27 @@ static void reparent_to_init(void) switch_uid(INIT_USER); } -void __set_special_pids(pid_t session, pid_t pgrp) +void __set_special_pids(struct pid *pid) { struct task_struct *curr = current->group_leader; + pid_t nr = pid_nr(pid); - if (process_session(curr) != session) { + if (task_session(curr) != pid) { detach_pid(curr, PIDTYPE_SID); - curr->signal->session = session; - attach_pid(curr, PIDTYPE_SID, session); + attach_pid(curr, PIDTYPE_SID, pid); + set_task_session(curr, nr); } - if (process_group(curr) != pgrp) { + if (task_pgrp(curr) != pid) { detach_pid(curr, PIDTYPE_PGID); - curr->signal->pgrp = pgrp; - attach_pid(curr, PIDTYPE_PGID, pgrp); + attach_pid(curr, PIDTYPE_PGID, pid); + set_task_pgrp(curr, nr); } } -static void set_special_pids(pid_t session, pid_t pgrp) +static void set_special_pids(struct pid *pid) { write_lock_irq(&tasklist_lock); - __set_special_pids(session, pgrp); + __set_special_pids(pid); write_unlock_irq(&tasklist_lock); } @@ -353,7 +379,7 @@ int disallow_signal(int sig) return -EINVAL; spin_lock_irq(¤t->sighand->siglock); - sigaddset(¤t->blocked, sig); + current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN; recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); return 0; @@ -382,8 +408,17 @@ void daemonize(const char *name, ...) * they would be locked into memory. */ exit_mm(current); + /* + * We don't want to have TIF_FREEZE set if the system-wide hibernation + * or suspend transition begins right now. + */ + current->flags |= PF_NOFREEZE; - set_special_pids(1, 1); + if (current->nsproxy != &init_nsproxy) { + get_nsproxy(&init_nsproxy); + switch_task_namespaces(current, &init_nsproxy); + } + set_special_pids(&init_struct_pid); proc_clear_tty(current); /* Block and flush all signals */ @@ -398,15 +433,11 @@ void daemonize(const char *name, ...) current->fs = fs; atomic_inc(&fs->count); - exit_task_namespaces(current); - current->nsproxy = init_task.nsproxy; - get_task_namespaces(current); - - exit_files(current); + exit_files(current); current->files = init_task.files; atomic_inc(¤t->files->count); - reparent_to_init(); + reparent_to_kthreadd(); } EXPORT_SYMBOL(daemonize); @@ -427,14 +458,16 @@ static void close_files(struct files_struct * files) for (;;) { unsigned long set; i = j * __NFDBITS; - if (i >= fdt->max_fdset || i >= fdt->max_fds) + if (i >= fdt->max_fds) break; set = fdt->open_fds->fds_bits[j++]; while (set) { if (set & 1) { struct file * file = xchg(&fdt->fd[i], NULL); - if (file) + if (file) { filp_close(file, files); + cond_resched(); + } } i++; set >>= 1; @@ -455,7 +488,7 @@ struct files_struct *get_files_struct(struct task_struct *task) return files; } -void fastcall put_files_struct(struct files_struct *files) +void put_files_struct(struct files_struct *files) { struct fdtable *fdt; @@ -468,9 +501,7 @@ void fastcall put_files_struct(struct files_struct *files) * you can free files immediately. */ fdt = files_fdtable(files); - if (fdt == &files->fdtab) - fdt->free_files = files; - else + if (fdt != &files->fdtab) kmem_cache_free(files_cachep, files); free_fdtable(fdt); } @@ -490,7 +521,7 @@ void reset_files_struct(struct task_struct *tsk, struct files_struct *files) } EXPORT_SYMBOL(reset_files_struct); -static inline void __exit_files(struct task_struct *tsk) +static void __exit_files(struct task_struct *tsk) { struct files_struct * files = tsk->files; @@ -507,18 +538,14 @@ void exit_files(struct task_struct *tsk) __exit_files(tsk); } -static inline void __put_fs_struct(struct fs_struct *fs) +static 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)) { - dput(fs->root); - mntput(fs->rootmnt); - dput(fs->pwd); - mntput(fs->pwdmnt); - if (fs->altroot) { - dput(fs->altroot); - mntput(fs->altrootmnt); - } + path_put(&fs->root); + path_put(&fs->pwd); + if (fs->altroot.dentry) + path_put(&fs->altroot); kmem_cache_free(fs_cachep, fs); } } @@ -528,7 +555,7 @@ void put_fs_struct(struct fs_struct *fs) __put_fs_struct(fs); } -static inline void __exit_fs(struct task_struct *tsk) +static void __exit_fs(struct task_struct *tsk) { struct fs_struct * fs = tsk->fs; @@ -583,28 +610,15 @@ static void exit_mm(struct task_struct * tsk) tsk->mm = NULL; up_read(&mm->mmap_sem); enter_lazy_tlb(mm, current); + /* We don't want this task to be frozen prematurely */ + clear_freeze_flag(tsk); task_unlock(tsk); mmput(mm); } -static inline void -choose_new_parent(struct task_struct *p, struct task_struct *reaper) -{ - /* - * Make sure we're not reparenting to ourselves and that - * the parent is not a zombie. - */ - BUG_ON(p == reaper || reaper->exit_state); - p->real_parent = reaper; -} - static void reparent_thread(struct task_struct *p, struct task_struct *father, int traced) { - /* We don't want people slaying init. */ - if (p->exit_signal != -1) - p->exit_signal = SIGCHLD; - if (p->pdeath_signal) /* We already hold the tasklist_lock here. */ group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p); @@ -624,13 +638,7 @@ reparent_thread(struct task_struct *p, struct task_struct *father, int traced) p->parent = p->real_parent; add_parent(p); - /* If we'd notified the old parent about this child's death, - * also notify the new parent. - */ - if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 && - thread_group_empty(p)) - do_notify_parent(p, p->exit_signal); - else if (p->state == TASK_TRACED) { + if (task_is_traced(p)) { /* * If it was at a trace stop, turn it into * a normal stop since it's no longer being @@ -640,43 +648,49 @@ reparent_thread(struct task_struct *p, struct task_struct *father, int traced) } } - /* - * process group orphan check - * Case ii: Our child is in a different pgrp - * than we are, and it was the only connection - * outside, so the child pgrp is now orphaned. + /* If this is a threaded reparent there is no need to + * notify anyone anything has happened. */ - if ((process_group(p) != process_group(father)) && - (process_session(p) == process_session(father))) { - int pgrp = process_group(p); - - if (will_become_orphaned_pgrp(pgrp, NULL) && - has_stopped_jobs(pgrp)) { - __kill_pg_info(SIGHUP, SEND_SIG_PRIV, pgrp); - __kill_pg_info(SIGCONT, SEND_SIG_PRIV, pgrp); - } - } + if (p->real_parent->group_leader == father->group_leader) + return; + + /* We don't want people slaying init. */ + if (p->exit_signal != -1) + p->exit_signal = SIGCHLD; + + /* If we'd notified the old parent about this child's death, + * also notify the new parent. + */ + if (!traced && p->exit_state == EXIT_ZOMBIE && + p->exit_signal != -1 && thread_group_empty(p)) + do_notify_parent(p, p->exit_signal); + + kill_orphaned_pgrp(p, father); } /* * When we die, we re-parent all our children. * Try to give them to another thread in our thread * group, and if no such member exists, give it to - * the global child reaper process (ie "init") + * the child reaper process (ie "init") in our pid + * space. */ -static void -forget_original_parent(struct task_struct *father, struct list_head *to_release) +static void forget_original_parent(struct task_struct *father) { - struct task_struct *p, *reaper = father; - struct list_head *_p, *_n; + 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 = child_reaper; + reaper = task_child_reaper(father); break; } - } while (reaper->exit_state); + } while (reaper->flags & PF_EXITING); /* * There are only two places where our children can be: @@ -686,9 +700,8 @@ forget_original_parent(struct task_struct *father, struct list_head *to_release) * * Search them and reparent children. */ - list_for_each_safe(_p, _n, &father->children) { + list_for_each_entry_safe(p, n, &father->children, sibling) { int ptrace; - p = list_entry(_p, struct task_struct, sibling); ptrace = p->ptrace; @@ -697,7 +710,7 @@ forget_original_parent(struct task_struct *father, struct list_head *to_release) if (father == p->real_parent) { /* reparent with a reaper, real father it's us */ - choose_new_parent(p, reaper); + p->real_parent = reaper; reparent_thread(p, father, 0); } else { /* reparent ptraced task to its real parent */ @@ -714,49 +727,32 @@ forget_original_parent(struct task_struct *father, struct list_head *to_release) * while it was being traced by us, to be able to see it in wait4. */ if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && p->exit_signal == -1)) - list_add(&p->ptrace_list, to_release); + list_add(&p->ptrace_list, &ptrace_dead); } - list_for_each_safe(_p, _n, &father->ptrace_children) { - p = list_entry(_p, struct task_struct, ptrace_list); - choose_new_parent(p, reaper); + + list_for_each_entry_safe(p, n, &father->ptrace_children, ptrace_list) { + p->real_parent = reaper; reparent_thread(p, father, 1); } + + 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); + } + } /* * Send signals to all our closest relatives so that they know * to properly mourn us.. */ -static void exit_notify(struct task_struct *tsk) +static void exit_notify(struct task_struct *tsk, int group_dead) { int state; - struct task_struct *t; - struct list_head ptrace_dead, *_p, *_n; - - if (signal_pending(tsk) && !(tsk->signal->flags & SIGNAL_GROUP_EXIT) - && !thread_group_empty(tsk)) { - /* - * This occurs when there was a race between our exit - * syscall and a group signal choosing us as the one to - * wake up. It could be that we are the only thread - * alerted to check for pending signals, but another thread - * should be woken now to take the signal since we will not. - * Now we'll wake all the threads in the group just to make - * sure someone gets all the pending signals. - */ - read_lock(&tasklist_lock); - spin_lock_irq(&tsk->sighand->siglock); - for (t = next_thread(tsk); t != tsk; t = next_thread(t)) - if (!signal_pending(t) && !(t->flags & PF_EXITING)) { - recalc_sigpending_tsk(t); - if (signal_pending(t)) - signal_wake_up(t, 0); - } - spin_unlock_irq(&tsk->sighand->siglock); - read_unlock(&tasklist_lock); - } - - write_lock_irq(&tasklist_lock); /* * This does two things: @@ -766,36 +762,17 @@ static void exit_notify(struct task_struct *tsk) * as a result of our exiting, and if they have any stopped * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) */ + forget_original_parent(tsk); + exit_task_namespaces(tsk); - INIT_LIST_HEAD(&ptrace_dead); - forget_original_parent(tsk, &ptrace_dead); - BUG_ON(!list_empty(&tsk->children)); - BUG_ON(!list_empty(&tsk->ptrace_children)); - - /* - * Check to see if any process groups have become orphaned - * as a result of our exiting, and if they have any stopped - * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) - * - * Case i: Our father is in a different pgrp than we are - * and we were the only connection outside, so our pgrp - * is about to become orphaned. - */ - - t = tsk->real_parent; - - if ((process_group(t) != process_group(tsk)) && - (process_session(t) == process_session(tsk)) && - will_become_orphaned_pgrp(process_group(tsk), tsk) && - has_stopped_jobs(process_group(tsk))) { - __kill_pg_info(SIGHUP, SEND_SIG_PRIV, process_group(tsk)); - __kill_pg_info(SIGCONT, SEND_SIG_PRIV, process_group(tsk)); - } + write_lock_irq(&tasklist_lock); + if (group_dead) + kill_orphaned_pgrp(tsk->group_leader, NULL); - /* Let father know we died + /* Let father know we died * * Thread signals are configurable, but you aren't going to use - * that to send signals to arbitary processes. + * that to send signals to arbitary processes. * That stops right now. * * If the parent exec id doesn't match the exec id we saved @@ -805,12 +782,10 @@ static void exit_notify(struct task_struct *tsk) * If our self_exec id doesn't match our parent_exec_id then * we have changed execution domain as these two values started * the same after a fork. - * */ - if (tsk->exit_signal != SIGCHLD && tsk->exit_signal != -1 && - ( tsk->parent_exec_id != t->self_exec_id || - tsk->self_exec_id != tsk->parent_exec_id) + (tsk->parent_exec_id != tsk->real_parent->self_exec_id || + tsk->self_exec_id != tsk->parent_exec_id) && !capable(CAP_KILL)) tsk->exit_signal = SIGCHLD; @@ -827,26 +802,84 @@ static void exit_notify(struct task_struct *tsk) } state = EXIT_ZOMBIE; - if (tsk->exit_signal == -1 && - (likely(tsk->ptrace == 0) || - unlikely(tsk->parent->signal->flags & SIGNAL_GROUP_EXIT))) + if (tsk->exit_signal == -1 && likely(!tsk->ptrace)) state = EXIT_DEAD; tsk->exit_state = state; - write_unlock_irq(&tasklist_lock); + if (thread_group_leader(tsk) && + tsk->signal->notify_count < 0 && + tsk->signal->group_exit_task) + wake_up_process(tsk->signal->group_exit_task); - list_for_each_safe(_p, _n, &ptrace_dead) { - list_del_init(_p); - t = list_entry(_p, struct task_struct, ptrace_list); - release_task(t); - } + write_unlock_irq(&tasklist_lock); /* If the process is dead, release it - nobody will wait for it */ if (state == EXIT_DEAD) release_task(tsk); } -fastcall NORET_TYPE void do_exit(long code) +#ifdef CONFIG_DEBUG_STACK_USAGE +static void check_stack_usage(void) +{ + static DEFINE_SPINLOCK(low_water_lock); + static int lowest_to_date = THREAD_SIZE; + unsigned long *n = end_of_stack(current); + unsigned long free; + + while (*n == 0) + n++; + free = (unsigned long)n - (unsigned long)end_of_stack(current); + + if (free >= lowest_to_date) + return; + + spin_lock(&low_water_lock); + if (free < lowest_to_date) { + printk(KERN_WARNING "%s used greatest stack depth: %lu bytes " + "left\n", + current->comm, free); + lowest_to_date = free; + } + spin_unlock(&low_water_lock); +} +#else +static inline void check_stack_usage(void) {} +#endif + +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; int group_dead; @@ -859,8 +892,6 @@ fastcall NORET_TYPE void do_exit(long code) panic("Aiee, killing interrupt handler!"); if (unlikely(!tsk->pid)) panic("Attempted to kill the idle task!"); - if (unlikely(tsk == child_reaper)) - panic("Attempted to kill init!"); if (unlikely(current->ptrace & PT_TRACE_EXIT)) { current->ptrace_message = code; @@ -874,17 +905,33 @@ fastcall NORET_TYPE void do_exit(long code) if (unlikely(tsk->flags & PF_EXITING)) { printk(KERN_ALERT "Fixing recursive fault but reboot is needed!\n"); + /* + * We can do this unlocked here. The futex code uses + * this flag just to verify whether the pi state + * cleanup has been done or not. In the worst case it + * loops once more. We pretend that the cleanup was + * done as there is no way to return. Either the + * OWNER_DIED bit is set by now or we push the blocked + * task into the wait for ever nirwana as well. + */ + tsk->flags |= PF_EXITPIDONE; if (tsk->io_context) exit_io_context(); set_current_state(TASK_UNINTERRUPTIBLE); schedule(); } - tsk->flags |= PF_EXITING; + exit_signals(tsk); /* sets PF_EXITING */ + /* + * tsk->flags are checked in the futex code to protect against + * an exiting task cleaning up the robust pi futexes. + */ + smp_mb(); + spin_unlock_wait(&tsk->pi_lock); if (unlikely(in_atomic())) printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n", - current->comm, current->pid, + current->comm, task_pid_nr(current), preempt_count()); acct_update_integrals(tsk); @@ -894,19 +941,25 @@ fastcall NORET_TYPE void do_exit(long code) } group_dead = atomic_dec_and_test(&tsk->signal->live); if (group_dead) { - hrtimer_cancel(&tsk->signal->real_timer); + 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); -#if defined(CONFIG_FUTEX) && defined(CONFIG_COMPAT) +#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)) audit_free(tsk); + tsk->exit_code = code; taskstats_exit(tsk, group_dead); exit_mm(tsk); @@ -916,8 +969,9 @@ fastcall NORET_TYPE void do_exit(long code) exit_sem(tsk); __exit_files(tsk); __exit_fs(tsk); + check_stack_usage(); exit_thread(); - cpuset_exit(tsk); + cgroup_exit(tsk, 1); exit_keys(tsk); if (group_dead && tsk->signal->leader) @@ -927,14 +981,13 @@ fastcall NORET_TYPE void do_exit(long code) if (tsk->binfmt) module_put(tsk->binfmt->module); - tsk->exit_code = code; proc_exit_connector(tsk); - exit_notify(tsk); - exit_task_namespaces(tsk); + exit_notify(tsk, group_dead); #ifdef CONFIG_NUMA mpol_free(tsk->mempolicy); tsk->mempolicy = NULL; #endif +#ifdef CONFIG_FUTEX /* * This must happen late, after the PID is not * hashed anymore: @@ -943,10 +996,17 @@ fastcall NORET_TYPE void do_exit(long code) exit_pi_state_list(tsk); if (unlikely(current->pi_state_cache)) kfree(current->pi_state_cache); +#endif /* * Make sure we are holding no locks: */ debug_check_no_locks_held(tsk); + /* + * We can do this unlocked here. The futex code uses this flag + * just to verify whether the pi state cleanup has been done + * or not. In the worst case it loops once more. + */ + tsk->flags |= PF_EXITPIDONE; if (tsk->io_context) exit_io_context(); @@ -997,11 +1057,12 @@ do_group_exit(int exit_code) struct signal_struct *const sig = current->signal; struct sighand_struct *const sighand = current->sighand; spin_lock_irq(&sighand->siglock); - if (sig->flags & SIGNAL_GROUP_EXIT) + if (signal_group_exit(sig)) /* Another thread got here before we took the lock. */ exit_code = sig->group_exit_code; else { sig->group_exit_code = exit_code; + sig->flags = SIGNAL_GROUP_EXIT; zap_other_threads(current); } spin_unlock_irq(&sighand->siglock); @@ -1021,16 +1082,23 @@ asmlinkage void sys_exit_group(int error_code) do_group_exit((error_code & 0xff) << 8); } -static int eligible_child(pid_t pid, int options, struct task_struct *p) +static struct pid *task_pid_type(struct task_struct *task, enum pid_type type) { - if (pid > 0) { - if (p->pid != pid) - return 0; - } else if (!pid) { - if (process_group(p) != process_group(current)) - return 0; - } else if (pid != -1) { - if (process_group(p) != -pid) + struct pid *pid = NULL; + if (type == PIDTYPE_PID) + pid = task->pids[type].pid; + else if (type < PIDTYPE_MAX) + pid = task->group_leader->pids[type].pid; + return pid; +} + +static int eligible_child(enum pid_type type, struct pid *pid, int options, + struct task_struct *p) +{ + int err; + + if (type < PIDTYPE_MAX) { + if (task_pid_type(p, type) != pid) return 0; } @@ -1049,17 +1117,16 @@ static int eligible_child(pid_t pid, int options, struct task_struct *p) if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0)) && !(options & __WALL)) return 0; - /* - * Do not consider thread group leaders that are - * in a non-empty thread group: - */ - if (delay_group_leader(p)) - return 2; - if (security_task_wait(p)) - return 0; + err = security_task_wait(p); + if (likely(!err)) + return 1; - return 1; + if (type != PIDTYPE_PID) + return 0; + /* This child was explicitly requested, abort */ + read_unlock(&tasklist_lock); + return err; } static int wait_noreap_copyout(struct task_struct *p, pid_t pid, uid_t uid, @@ -1098,19 +1165,14 @@ static int wait_task_zombie(struct task_struct *p, int noreap, int __user *stat_addr, struct rusage __user *ru) { unsigned long state; - int retval; - int status; + int retval, status, traced; + pid_t pid = task_pid_vnr(p); if (unlikely(noreap)) { - pid_t pid = p->pid; uid_t uid = p->uid; int exit_code = p->exit_code; int why, status; - if (unlikely(p->exit_state != EXIT_ZOMBIE)) - return 0; - if (unlikely(p->exit_signal == -1 && p->ptrace == 0)) - return 0; get_task_struct(p); read_unlock(&tasklist_lock); if ((exit_code & 0x7f) == 0) { @@ -1133,15 +1195,11 @@ static int wait_task_zombie(struct task_struct *p, int noreap, BUG_ON(state != EXIT_DEAD); return 0; } - if (unlikely(p->exit_signal == -1 && p->ptrace == 0)) { - /* - * This can only happen in a race with a ptraced thread - * dying on another processor. - */ - return 0; - } - if (likely(p->real_parent == p->parent) && likely(p->signal)) { + /* traced means p->ptrace, but not vice versa */ + traced = (p->real_parent != p->parent); + + if (likely(!traced)) { struct signal_struct *psig; struct signal_struct *sig; @@ -1173,6 +1231,11 @@ static int wait_task_zombie(struct task_struct *p, int noreap, cputime_add(p->stime, cputime_add(sig->stime, sig->cstime))); + psig->cgtime = + cputime_add(psig->cgtime, + cputime_add(p->gtime, + cputime_add(sig->gtime, + sig->cgtime))); psig->cmin_flt += p->min_flt + sig->min_flt + sig->cmin_flt; psig->cmaj_flt += @@ -1181,6 +1244,12 @@ static int wait_task_zombie(struct task_struct *p, int noreap, p->nvcsw + sig->nvcsw + sig->cnvcsw; psig->cnivcsw += p->nivcsw + sig->nivcsw + sig->cnivcsw; + psig->cinblock += + task_io_get_inblock(p) + + sig->inblock + sig->cinblock; + psig->coublock += + task_io_get_oublock(p) + + sig->oublock + sig->coublock; spin_unlock_irq(&p->parent->sighand->siglock); } @@ -1214,38 +1283,33 @@ static int wait_task_zombie(struct task_struct *p, int noreap, retval = put_user(status, &infop->si_status); } if (!retval && infop) - retval = put_user(p->pid, &infop->si_pid); + retval = put_user(pid, &infop->si_pid); if (!retval && infop) retval = put_user(p->uid, &infop->si_uid); - if (retval) { - // TODO: is this safe? - p->exit_state = EXIT_ZOMBIE; - return retval; - } - retval = p->pid; - if (p->real_parent != p->parent) { + if (!retval) + retval = pid; + + if (traced) { write_lock_irq(&tasklist_lock); - /* Double-check with lock held. */ - if (p->real_parent != p->parent) { - __ptrace_unlink(p); - // TODO: is this safe? - p->exit_state = EXIT_ZOMBIE; - /* - * If this is not a detached task, notify the parent. - * If it's still not detached after that, don't release - * it now. - */ + /* We dropped tasklist, ptracer could die and untrace */ + ptrace_unlink(p); + /* + * If this is not a detached task, notify the parent. + * If it's still not detached after that, don't release + * it now. + */ + if (p->exit_signal != -1) { + do_notify_parent(p, p->exit_signal); if (p->exit_signal != -1) { - do_notify_parent(p, p->exit_signal); - if (p->exit_signal != -1) - p = NULL; + p->exit_state = EXIT_ZOMBIE; + p = NULL; } } write_unlock_irq(&tasklist_lock); } if (p != NULL) release_task(p); - BUG_ON(!retval); + return retval; } @@ -1255,20 +1319,38 @@ static int wait_task_zombie(struct task_struct *p, int noreap, * 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, int delayed_group_leader, +static int wait_task_stopped(struct task_struct *p, int noreap, struct siginfo __user *infop, int __user *stat_addr, struct rusage __user *ru) { - int retval, exit_code; + int retval, exit_code, why; + uid_t uid = 0; /* unneeded, required by compiler */ + pid_t pid; - if (!p->exit_code) - return 0; - if (delayed_group_leader && !(p->ptrace & PT_PTRACED) && - p->signal && p->signal->group_stop_count > 0) + exit_code = 0; + spin_lock_irq(&p->sighand->siglock); + + if (unlikely(!task_is_stopped_or_traced(p))) + goto unlock_sig; + + if (!(p->ptrace & PT_PTRACED) && p->signal->group_stop_count > 0) /* * A group stop is in progress and this is the group leader. * We won't report until all threads have stopped. */ + goto unlock_sig; + + exit_code = p->exit_code; + if (!exit_code) + goto unlock_sig; + + if (!noreap) + p->exit_code = 0; + + uid = p->uid; +unlock_sig: + spin_unlock_irq(&p->sighand->siglock); + if (!exit_code) return 0; /* @@ -1279,65 +1361,14 @@ static int wait_task_stopped(struct task_struct *p, int delayed_group_leader, * possibly take page faults for user memory. */ get_task_struct(p); + pid = task_pid_vnr(p); + why = (p->ptrace & PT_PTRACED) ? CLD_TRAPPED : CLD_STOPPED; read_unlock(&tasklist_lock); - if (unlikely(noreap)) { - pid_t pid = p->pid; - uid_t uid = p->uid; - int why = (p->ptrace & PT_PTRACED) ? CLD_TRAPPED : CLD_STOPPED; - - exit_code = p->exit_code; - if (unlikely(!exit_code) || - unlikely(p->state & TASK_TRACED)) - goto bail_ref; + if (unlikely(noreap)) return wait_noreap_copyout(p, pid, uid, - why, (exit_code << 8) | 0x7f, + why, exit_code, infop, ru); - } - - write_lock_irq(&tasklist_lock); - - /* - * This uses xchg to be atomic with the thread resuming and setting - * it. It must also be done with the write lock held to prevent a - * race with the EXIT_ZOMBIE case. - */ - exit_code = xchg(&p->exit_code, 0); - if (unlikely(p->exit_state)) { - /* - * The task resumed and then died. Let the next iteration - * catch it in EXIT_ZOMBIE. Note that exit_code might - * already be zero here if it resumed and did _exit(0). - * The task itself is dead and won't touch exit_code again; - * other processors in this function are locked out. - */ - p->exit_code = exit_code; - exit_code = 0; - } - if (unlikely(exit_code == 0)) { - /* - * Another thread in this function got to it first, or it - * resumed, or it resumed and then died. - */ - write_unlock_irq(&tasklist_lock); -bail_ref: - put_task_struct(p); - /* - * We are returning to the wait loop without having successfully - * removed the process and having released the lock. We cannot - * continue, since the "p" task pointer is potentially stale. - * - * Return -EAGAIN, and do_wait() will restart the loop from the - * beginning. Do _not_ re-acquire the lock. - */ - return -EAGAIN; - } - - /* move to end of parent's list to avoid starvation */ - remove_parent(p); - add_parent(p); - - write_unlock_irq(&tasklist_lock); retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; if (!retval && stat_addr) @@ -1347,17 +1378,15 @@ bail_ref: if (!retval && infop) retval = put_user(0, &infop->si_errno); if (!retval && infop) - retval = put_user((short)((p->ptrace & PT_PTRACED) - ? CLD_TRAPPED : CLD_STOPPED), - &infop->si_code); + retval = put_user((short)why, &infop->si_code); if (!retval && infop) retval = put_user(exit_code, &infop->si_status); if (!retval && infop) - retval = put_user(p->pid, &infop->si_pid); + 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 = p->pid; + retval = pid; put_task_struct(p); BUG_ON(!retval); @@ -1378,9 +1407,6 @@ static int wait_task_continued(struct task_struct *p, int noreap, pid_t pid; uid_t uid; - if (unlikely(!p->signal)) - return 0; - if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) return 0; @@ -1394,7 +1420,7 @@ static int wait_task_continued(struct task_struct *p, int noreap, p->signal->flags &= ~SIGNAL_STOP_CONTINUED; spin_unlock_irq(&p->sighand->siglock); - pid = p->pid; + pid = task_pid_vnr(p); uid = p->uid; get_task_struct(p); read_unlock(&tasklist_lock); @@ -1405,7 +1431,7 @@ static int wait_task_continued(struct task_struct *p, int noreap, if (!retval && stat_addr) retval = put_user(0xffff, stat_addr); if (!retval) - retval = p->pid; + retval = pid; } else { retval = wait_noreap_copyout(p, pid, uid, CLD_CONTINUED, SIGCONT, @@ -1416,25 +1442,9 @@ static int wait_task_continued(struct task_struct *p, int noreap, return retval; } - -static inline int my_ptrace_child(struct task_struct *p) -{ - if (!(p->ptrace & PT_PTRACED)) - return 0; - if (!(p->ptrace & PT_ATTACHED)) - return 1; - /* - * This child was PTRACE_ATTACH'd. We should be seeing it only if - * we are the attacher. If we are the real parent, this is a race - * inside ptrace_attach. It is waiting for the tasklist_lock, - * which we have to switch the parent links, but has already set - * the flags in p->ptrace. - */ - return (p->parent != p->real_parent); -} - -static long do_wait(pid_t pid, int options, struct siginfo __user *infop, - int __user *stat_addr, struct rusage __user *ru) +static long do_wait(enum pid_type type, struct pid *pid, int options, + struct siginfo __user *infop, int __user *stat_addr, + struct rusage __user *ru) { DECLARE_WAITQUEUE(wait, current); struct task_struct *tsk; @@ -1442,81 +1452,53 @@ static long do_wait(pid_t pid, int options, struct siginfo __user *infop, add_wait_queue(¤t->signal->wait_chldexit,&wait); repeat: + /* If there is nothing that can match our critier just get out */ + retval = -ECHILD; + if ((type < PIDTYPE_MAX) && (!pid || hlist_empty(&pid->tasks[type]))) + goto end; + /* * We will set this flag if we see any child that might later * match our criteria, even if we are not able to reap it yet. */ - flag = 0; + flag = retval = 0; current->state = TASK_INTERRUPTIBLE; read_lock(&tasklist_lock); tsk = current; do { struct task_struct *p; - struct list_head *_p; - int ret; - - list_for_each(_p,&tsk->children) { - p = list_entry(_p, struct task_struct, sibling); - ret = eligible_child(pid, options, p); + list_for_each_entry(p, &tsk->children, sibling) { + int ret = eligible_child(type, pid, options, p); if (!ret) continue; - switch (p->state) { - case TASK_TRACED: - /* - * When we hit the race with PTRACE_ATTACH, - * we will not report this child. But the - * race means it has not yet been moved to - * our ptrace_children list, so we need to - * set the flag here to avoid a spurious ECHILD - * when the race happens with the only child. - */ - flag = 1; - if (!my_ptrace_child(p)) - continue; - /*FALLTHROUGH*/ - case TASK_STOPPED: + if (unlikely(ret < 0)) { + retval = ret; + } else if (task_is_stopped_or_traced(p)) { /* * It's stopped now, so it might later * continue, exit, or stop again. */ flag = 1; - if (!(options & WUNTRACED) && - !my_ptrace_child(p)) + if (!(p->ptrace & PT_PTRACED) && + !(options & WUNTRACED)) continue; - retval = wait_task_stopped(p, ret == 2, - (options & WNOWAIT), - infop, - stat_addr, ru); - if (retval == -EAGAIN) - goto repeat; - if (retval != 0) /* He released the lock. */ - goto end; - break; - default: - // case EXIT_DEAD: - if (p->exit_state == EXIT_DEAD) + + retval = wait_task_stopped(p, + (options & WNOWAIT), infop, + stat_addr, ru); + } else if (p->exit_state == EXIT_ZOMBIE && + !delay_group_leader(p)) { + /* + * We don't reap group leaders with subthreads. + */ + if (!likely(options & WEXITED)) continue; - // case EXIT_ZOMBIE: - if (p->exit_state == EXIT_ZOMBIE) { - /* - * Eligible but we cannot release - * it yet: - */ - if (ret == 2) - goto check_continued; - if (!likely(options & WEXITED)) - continue; - retval = wait_task_zombie( - p, (options & WNOWAIT), - infop, stat_addr, ru); - /* He released the lock. */ - if (retval != 0) - goto end; - break; - } -check_continued: + retval = wait_task_zombie(p, + (options & WNOWAIT), infop, + stat_addr, ru); + } else if (p->exit_state != EXIT_DEAD) { /* * It's running now, so it might later * exit, stop, or stop and then continue. @@ -1524,22 +1506,23 @@ check_continued: flag = 1; if (!unlikely(options & WCONTINUED)) continue; - retval = wait_task_continued( - p, (options & WNOWAIT), - infop, stat_addr, ru); - if (retval != 0) /* He released the lock. */ - goto end; - break; + retval = wait_task_continued(p, + (options & WNOWAIT), infop, + stat_addr, ru); } + if (retval != 0) /* tasklist_lock released */ + goto end; } if (!flag) { - list_for_each(_p, &tsk->ptrace_children) { - p = list_entry(_p, struct task_struct, - ptrace_list); - if (!eligible_child(pid, options, p)) + list_for_each_entry(p, &tsk->ptrace_children, + ptrace_list) { + flag = eligible_child(type, pid, options, p); + if (!flag) continue; - flag = 1; - break; + if (likely(flag > 0)) + break; + retval = flag; + goto end; } } if (options & __WNOTHREAD) @@ -1547,10 +1530,9 @@ check_continued: tsk = next_thread(tsk); BUG_ON(tsk->signal != current->signal); } while (tsk != current); - read_unlock(&tasklist_lock); + if (flag) { - retval = 0; if (options & WNOHANG) goto end; retval = -ERESTARTSYS; @@ -1565,7 +1547,7 @@ end: remove_wait_queue(¤t->signal->wait_chldexit,&wait); if (infop) { if (retval > 0) - retval = 0; + retval = 0; else { /* * For a WNOHANG return, clear out all the fields @@ -1589,10 +1571,12 @@ end: return retval; } -asmlinkage long sys_waitid(int which, pid_t pid, +asmlinkage long sys_waitid(int which, pid_t upid, struct siginfo __user *infop, int options, struct rusage __user *ru) { + struct pid *pid = NULL; + enum pid_type type; long ret; if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED)) @@ -1602,40 +1586,61 @@ asmlinkage long sys_waitid(int which, pid_t pid, switch (which) { case P_ALL: - pid = -1; + type = PIDTYPE_MAX; break; case P_PID: - if (pid <= 0) + type = PIDTYPE_PID; + if (upid <= 0) return -EINVAL; break; case P_PGID: - if (pid <= 0) + type = PIDTYPE_PGID; + if (upid <= 0) return -EINVAL; - pid = -pid; break; default: return -EINVAL; } - ret = do_wait(pid, options, infop, NULL, ru); + if (type < PIDTYPE_MAX) + pid = find_get_pid(upid); + ret = do_wait(type, pid, options, infop, NULL, ru); + put_pid(pid); /* avoid REGPARM breakage on x86: */ - prevent_tail_call(ret); + asmlinkage_protect(5, ret, which, upid, infop, options, ru); return ret; } -asmlinkage long sys_wait4(pid_t pid, int __user *stat_addr, +asmlinkage long sys_wait4(pid_t upid, int __user *stat_addr, int options, struct rusage __user *ru) { + struct pid *pid = NULL; + enum pid_type type; long ret; if (options & ~(WNOHANG|WUNTRACED|WCONTINUED| __WNOTHREAD|__WCLONE|__WALL)) return -EINVAL; - ret = do_wait(pid, options | WEXITED, NULL, stat_addr, ru); + + if (upid == -1) + type = PIDTYPE_MAX; + else if (upid < 0) { + type = PIDTYPE_PGID; + pid = find_get_pid(-upid); + } else if (upid == 0) { + type = PIDTYPE_PGID; + pid = get_pid(task_pgrp(current)); + } else /* upid > 0 */ { + type = PIDTYPE_PID; + pid = find_get_pid(upid); + } + + ret = do_wait(type, pid, options | WEXITED, NULL, stat_addr, ru); + put_pid(pid); /* avoid REGPARM breakage on x86: */ - prevent_tail_call(ret); + asmlinkage_protect(4, ret, upid, stat_addr, options, ru); return ret; }