copy_process() does a lot of "chaotic" initializations and checks
CLONE_THREAD twice before it takes tasklist. In particular it sets
"p->group_leader = p" and then changes it again under tasklist if
!thread_group_leader(p).
This looks a bit confusing, lets create a single "if (CLONE_THREAD)" block
which initializes ->exit_signal, ->group_leader, and ->tgid.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Sergey Dyasly <dserrg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
goto bad_fork_cleanup_io;
}
goto bad_fork_cleanup_io;
}
- p->pid = pid_nr(pid);
- p->tgid = p->pid;
- if (clone_flags & CLONE_THREAD)
- p->tgid = current->tgid;
-
p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
/*
* Clear TID on mm_release()?
p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
/*
* Clear TID on mm_release()?
clear_all_latency_tracing(p);
/* ok, now we should be set up.. */
clear_all_latency_tracing(p);
/* ok, now we should be set up.. */
- if (clone_flags & CLONE_THREAD)
+ p->pid = pid_nr(pid);
+ if (clone_flags & CLONE_THREAD) {
- else if (clone_flags & CLONE_PARENT)
- p->exit_signal = current->group_leader->exit_signal;
- else
- p->exit_signal = (clone_flags & CSIGNAL);
+ p->group_leader = current->group_leader;
+ p->tgid = current->tgid;
+ } else {
+ if (clone_flags & CLONE_PARENT)
+ p->exit_signal = current->group_leader->exit_signal;
+ else
+ p->exit_signal = (clone_flags & CSIGNAL);
+ p->group_leader = p;
+ p->tgid = p->pid;
+ }
p->pdeath_signal = 0;
p->exit_state = 0;
p->pdeath_signal = 0;
p->exit_state = 0;
p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10);
p->dirty_paused_when = 0;
p->nr_dirtied_pause = 128 >> (PAGE_SHIFT - 10);
p->dirty_paused_when = 0;
- /*
- * Ok, make it visible to the rest of the system.
- * We dont wake it up yet.
- */
- p->group_leader = p;
INIT_LIST_HEAD(&p->thread_group);
p->task_works = NULL;
INIT_LIST_HEAD(&p->thread_group);
p->task_works = NULL;
- /* Need tasklist lock for parent etc handling! */
+ /*
+ * Make it visible to the rest of the system, but dont wake it up yet.
+ * Need tasklist lock for parent etc handling!
+ */
write_lock_irq(&tasklist_lock);
/* CLONE_PARENT re-uses the old parent */
write_lock_irq(&tasklist_lock);
/* CLONE_PARENT re-uses the old parent */
current->signal->nr_threads++;
atomic_inc(¤t->signal->live);
atomic_inc(¤t->signal->sigcnt);
current->signal->nr_threads++;
atomic_inc(¤t->signal->live);
atomic_inc(¤t->signal->sigcnt);
- p->group_leader = current->group_leader;
list_add_tail_rcu(&p->thread_group,
&p->group_leader->thread_group);
}
list_add_tail_rcu(&p->thread_group,
&p->group_leader->thread_group);
}