X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fexit.c;h=ad8375758a79c3ad4d0a9aefa4b990ef2e977cef;hb=3e93cd671813e204c258f1e6c797959920cf7772;hp=a2af6cac823c2fd42744e4d2e20e667a71b876f2;hpb=14dd0b81414a58caf0296dbeace016bb0a5d11ab;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/exit.c b/kernel/exit.c index a2af6ca..ad83757 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -40,17 +40,24 @@ #include #include #include -#include #include #include /* for audit_free() */ #include #include #include +#include +#include +#include #include #include #include #include +#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); @@ -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. */ } @@ -136,43 +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); -/* - * 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); /* @@ -194,6 +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); @@ -337,12 +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) @@ -415,7 +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); @@ -432,7 +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); @@ -448,11 +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(¤t->files->count); @@ -551,32 +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 @@ -588,8 +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) @@ -632,6 +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: @@ -652,7 +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); @@ -666,26 +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); @@ -703,6 +703,23 @@ 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. * @@ -711,6 +728,7 @@ static void exit_mm(struct task_struct * tsk) 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); @@ -726,10 +744,18 @@ static void ptrace_exit(struct task_struct *parent, struct list_head *dead) * 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)) { @@ -796,26 +822,50 @@ static void reparent_thread(struct task_struct *p, struct task_struct *father) * the child reaper process (ie "init") in our pid * space. */ +static struct task_struct *find_new_reaper(struct task_struct *father) +{ + struct pid_namespace *pid_ns = task_active_pid_ns(father); + struct task_struct *thread; + + 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); + /* + * 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. + */ + pid_ns->child_reaper = init_pid_ns.child_reaper; + } + + return pid_ns->child_reaper; +} + static void forget_original_parent(struct task_struct *father) { - struct task_struct *p, *n, *reaper = 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); - do { - reaper = next_thread(reaper); - if (reaper == father) { - reaper = task_child_reaper(father); - break; - } - } while (reaper->flags & PF_EXITING); - list_for_each_entry_safe(p, n, &father->children, sibling) { p->real_parent = reaper; if (p->parent == father) { @@ -837,7 +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: @@ -874,33 +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); } @@ -909,12 +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; @@ -932,39 +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; @@ -979,10 +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 @@ -1001,8 +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(); } @@ -1021,25 +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)) @@ -1052,13 +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); @@ -1103,7 +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". */ @@ -1123,7 +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); } @@ -1164,9 +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) @@ -1243,12 +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; @@ -1280,6 +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 @@ -1295,20 +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, @@ -1328,6 +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); } @@ -1363,7 +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; @@ -1428,7 +1425,8 @@ static int wait_task_stopped(int ptrace, 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) @@ -1502,10 +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); @@ -1651,6 +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(¤t->signal->wait_chldexit,&wait); repeat: /* @@ -1725,9 +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; @@ -1766,8 +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; @@ -1804,7 +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); }