X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fexit.c;h=e06d0c10a24e2f4e054d17c21d032beadf8d1ba6;hb=35189fad3cb5f6e3ab66c8321928a851de0cd2b1;hp=a94e1c31131bf71308d340030f6de766c0e09cf2;hpb=73b9ebfe126a4a886ee46cbab637374d7024668a;p=linux-2.6 diff --git a/kernel/exit.c b/kernel/exit.c index a94e1c3113..e06d0c10a2 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -29,10 +29,13 @@ #include #include #include +#include #include #include #include #include +#include +#include /* for audit_free() */ #include #include @@ -50,39 +53,101 @@ static void __unhash_process(struct task_struct *p) { nr_threads--; detach_pid(p, PIDTYPE_PID); - detach_pid(p, PIDTYPE_TGID); if (thread_group_leader(p)) { detach_pid(p, PIDTYPE_PGID); detach_pid(p, PIDTYPE_SID); - list_del_init(&p->tasks); + list_del_rcu(&p->tasks); __get_cpu_var(process_counts)--; } - + list_del_rcu(&p->thread_group); remove_parent(p); } +/* + * This function expects the tasklist_lock write-locked. + */ +static void __exit_signal(struct task_struct *tsk) +{ + struct signal_struct *sig = tsk->signal; + struct sighand_struct *sighand; + + BUG_ON(!sig); + BUG_ON(!atomic_read(&sig->count)); + + rcu_read_lock(); + sighand = rcu_dereference(tsk->sighand); + spin_lock(&sighand->siglock); + + posix_cpu_timers_exit(tsk); + if (atomic_dec_and_test(&sig->count)) + posix_cpu_timers_exit_group(tsk); + else { + /* + * 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) { + wake_up_process(sig->group_exit_task); + sig->group_exit_task = NULL; + } + if (tsk == sig->curr_target) + sig->curr_target = next_thread(tsk); + /* + * Accumulate here the counters for all threads but the + * group leader as they die, so they can be added into + * the process-wide totals when those are taken. + * The group leader stays around as a zombie as long + * as there are other threads. When it gets reaped, + * the exit.c code will add its counts into these totals. + * 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->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 = NULL; /* Marker for below. */ + } + + __unhash_process(tsk); + + tsk->signal = NULL; + tsk->sighand = NULL; + spin_unlock(&sighand->siglock); + rcu_read_unlock(); + + __cleanup_sighand(sighand); + clear_tsk_thread_flag(tsk,TIF_SIGPENDING); + flush_sigqueue(&tsk->pending); + if (sig) { + flush_sigqueue(&sig->shared_pending); + __cleanup_signal(sig); + } +} + +static void delayed_put_task_struct(struct rcu_head *rhp) +{ + put_task_struct(container_of(rhp, struct task_struct, rcu)); +} + void release_task(struct task_struct * p) { int zap_leader; task_t *leader; struct dentry *proc_dentry; -repeat: +repeat: atomic_dec(&p->user->processes); spin_lock(&p->proc_lock); proc_dentry = proc_pid_unhash(p); write_lock_irq(&tasklist_lock); - if (unlikely(p->ptrace)) - __ptrace_unlink(p); + ptrace_unlink(p); BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children)); __exit_signal(p); - /* - * Note that the fastpath in sys_times depends on __exit_signal having - * updated the counters before a task is removed from the tasklist of - * the process by __unhash_process. - */ - __unhash_process(p); /* * If we are the last non-leader member of the thread @@ -110,7 +175,7 @@ repeat: spin_unlock(&p->proc_lock); proc_pid_flush(proc_dentry); release_thread(p); - put_task_struct(p); + call_rcu(&p->rcu, delayed_put_task_struct); p = leader; if (unlikely(zap_leader)) @@ -555,9 +620,9 @@ static void reparent_thread(task_t *p, task_t *father, int traced) * anyway, so let go of it. */ p->ptrace = 0; - list_del_init(&p->sibling); + remove_parent(p); p->parent = p->real_parent; - list_add_tail(&p->sibling, &p->parent->children); + add_parent(p); /* If we'd notified the old parent about this child's death, * also notify the new parent. @@ -816,14 +881,6 @@ fastcall NORET_TYPE void do_exit(long code) tsk->flags |= PF_EXITING; - /* - * Make sure we don't try to process any timer firings - * while we are already exiting. - */ - tsk->it_virt_expires = cputime_zero; - tsk->it_prof_expires = cputime_zero; - tsk->it_sched_expires = 0; - if (unlikely(in_atomic())) printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n", current->comm, current->pid, @@ -846,6 +903,8 @@ fastcall NORET_TYPE void do_exit(long code) if (unlikely(tsk->compat_robust_list)) compat_exit_robust_list(tsk); #endif + if (unlikely(tsk->audit_context)) + audit_free(tsk); exit_mm(tsk); exit_sem(tsk); @@ -878,6 +937,9 @@ fastcall NORET_TYPE void do_exit(long code) if (tsk->io_context) exit_io_context(); + if (tsk->splice_pipe) + __free_pipe_info(tsk->splice_pipe); + /* PF_DEAD causes final put_task_struct after we schedule. */ preempt_disable(); BUG_ON(tsk->flags & PF_DEAD); @@ -906,13 +968,6 @@ asmlinkage long sys_exit(int error_code) do_exit((error_code&0xff)<<8); } -task_t fastcall *next_thread(const task_t *p) -{ - return pid_task(p->pids[PIDTYPE_TGID].pid_list.next, PIDTYPE_TGID); -} - -EXPORT_SYMBOL(next_thread); - /* * Take down every thread in the group. This is called by fatal signals * as well as by sys_exit_group (below). @@ -927,7 +982,6 @@ do_group_exit(int exit_code) else if (!thread_group_empty(current)) { struct signal_struct *const sig = current->signal; struct sighand_struct *const sighand = current->sighand; - read_lock(&tasklist_lock); spin_lock_irq(&sighand->siglock); if (sig->flags & SIGNAL_GROUP_EXIT) /* Another thread got here before we took the lock. */ @@ -937,7 +991,6 @@ do_group_exit(int exit_code) zap_other_threads(current); } spin_unlock_irq(&sighand->siglock); - read_unlock(&tasklist_lock); } do_exit(exit_code);