static void reparent_leader(struct task_struct *father, struct task_struct *p,
struct list_head *dead)
{
- list_move_tail(&p->sibling, &p->real_parent->children);
-
- if (p->exit_state == EXIT_DEAD)
- 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))
+ if (unlikely(p->exit_state == EXIT_DEAD))
return;
/* We don't want people slaying init. */
p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) {
if (do_notify_parent(p, p->exit_signal)) {
p->exit_state = EXIT_DEAD;
- list_move_tail(&p->sibling, dead);
+ list_add(&p->ptrace_entry, dead);
}
}
static void forget_original_parent(struct task_struct *father)
{
- struct task_struct *p, *n, *reaper;
+ struct task_struct *p, *t, *n, *reaper;
LIST_HEAD(dead_children);
write_lock_irq(&tasklist_lock);
- /*
- * Note that exit_ptrace() and find_new_reaper() might
- * drop tasklist_lock and reacquire it.
- */
- exit_ptrace(father);
- reaper = find_new_reaper(father);
-
- list_for_each_entry_safe(p, n, &father->children, sibling) {
- struct task_struct *t = p;
+ if (unlikely(!list_empty(&father->ptraced)))
+ exit_ptrace(father, &dead_children);
- do {
+ /* Can drop and reacquire tasklist_lock */
+ reaper = find_new_reaper(father);
+ list_for_each_entry(p, &father->children, sibling) {
+ for_each_thread(p, t) {
t->real_parent = reaper;
- if (t->parent == father) {
- BUG_ON(t->ptrace);
+ BUG_ON((!t->ptrace) != (t->parent == father));
+ if (likely(!t->ptrace))
t->parent = t->real_parent;
- }
if (t->pdeath_signal)
group_send_sig_info(t->pdeath_signal,
SEND_SIG_NOINFO, t);
- } while_each_thread(p, t);
- reparent_leader(father, p, &dead_children);
+ }
+ /*
+ * If this is a threaded reparent there is no need to
+ * notify anyone anything has happened.
+ */
+ if (!same_thread_group(reaper, father))
+ reparent_leader(father, p, &dead_children);
}
+ list_splice_tail_init(&father->children, &reaper->children);
write_unlock_irq(&tasklist_lock);
- BUG_ON(!list_empty(&father->children));
-
- list_for_each_entry_safe(p, n, &dead_children, sibling) {
- list_del_init(&p->sibling);
+ list_for_each_entry_safe(p, n, &dead_children, ptrace_entry) {
+ list_del_init(&p->ptrace_entry);
release_task(p);
}
}
*/
static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
{
- unsigned long state;
- int retval, status, traced;
+ int state, retval, status;
pid_t pid = task_pid_vnr(p);
uid_t uid = from_kuid_munged(current_user_ns(), task_uid(p));
struct siginfo __user *infop;
get_task_struct(p);
read_unlock(&tasklist_lock);
+ sched_annotate_sleep();
+
if ((exit_code & 0x7f) == 0) {
why = CLD_EXITED;
status = exit_code >> 8;
}
return wait_noreap_copyout(wo, p, pid, uid, why, status);
}
-
- traced = ptrace_reparented(p);
/*
* Move the task's state to DEAD/TRACE, only one thread can do this.
*/
- state = traced && thread_group_leader(p) ? EXIT_TRACE : EXIT_DEAD;
+ state = (ptrace_reparented(p) && thread_group_leader(p)) ?
+ EXIT_TRACE : EXIT_DEAD;
if (cmpxchg(&p->exit_state, EXIT_ZOMBIE, state) != EXIT_ZOMBIE)
return 0;
/*
- * It can be ptraced but not reparented, check
- * thread_group_leader() to filter out sub-threads.
+ * We own this thread, nobody else can reap it.
*/
- if (likely(!traced) && thread_group_leader(p)) {
- struct signal_struct *psig;
- struct signal_struct *sig;
+ read_unlock(&tasklist_lock);
+ sched_annotate_sleep();
+
+ /*
+ * Check thread_group_leader() to exclude the traced sub-threads.
+ */
+ if (state == EXIT_DEAD && thread_group_leader(p)) {
+ struct signal_struct *sig = p->signal;
+ struct signal_struct *psig = current->signal;
unsigned long maxrss;
cputime_t tgutime, tgstime;
* accumulate in the parent's signal_struct c* fields.
*
* We don't bother to take a lock here to protect these
- * p->signal fields, because they are only touched by
- * __exit_signal, which runs with tasklist_lock
- * write-locked anyway, and so is excluded here. We do
- * need to protect the access to parent->signal fields,
- * as other threads in the parent group can be right
- * here reaping other children at the same time.
+ * p->signal fields because the whole thread group is dead
+ * and nobody can change them.
+ *
+ * psig->stats_lock also protects us from our sub-theads
+ * which can reap other children at the same time. Until
+ * we change k_getrusage()-like users to rely on this lock
+ * we have to take ->siglock as well.
*
* We use thread_group_cputime_adjusted() to get times for
* the thread group, which consolidates times for all threads
* in the group including the group leader.
*/
thread_group_cputime_adjusted(p, &tgutime, &tgstime);
- spin_lock_irq(&p->real_parent->sighand->siglock);
- psig = p->real_parent->signal;
- sig = p->signal;
+ spin_lock_irq(¤t->sighand->siglock);
write_seqlock(&psig->stats_lock);
psig->cutime += tgutime + sig->cutime;
psig->cstime += tgstime + sig->cstime;
task_io_accounting_add(&psig->ioac, &p->ioac);
task_io_accounting_add(&psig->ioac, &sig->ioac);
write_sequnlock(&psig->stats_lock);
- spin_unlock_irq(&p->real_parent->sighand->siglock);
+ spin_unlock_irq(¤t->sighand->siglock);
}
- /*
- * Now we are sure this task is interesting, and no other
- * thread can reap it because we its state == DEAD/TRACE.
- */
- read_unlock(&tasklist_lock);
-
retval = wo->wo_rusage
? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
status = (p->signal->flags & SIGNAL_GROUP_EXIT)
pid = task_pid_vnr(p);
why = ptrace ? CLD_TRAPPED : CLD_STOPPED;
read_unlock(&tasklist_lock);
+ sched_annotate_sleep();
if (unlikely(wo->wo_flags & WNOWAIT))
return wait_noreap_copyout(wo, p, pid, uid, why, exit_code);
pid = task_pid_vnr(p);
get_task_struct(p);
read_unlock(&tasklist_lock);
+ sched_annotate_sleep();
if (!wo->wo_info) {
retval = wo->wo_rusage
projects / cascardo / linux.git / blobdiff