diff options
author | Oleg Nesterov <oleg@redhat.com> | 2009-04-02 16:58:19 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-02 19:05:00 -0700 |
commit | 5dfc80be73dd0c212d2e6dd8dbf5afa07e680bbe (patch) | |
tree | ac173fb3fcfe2970781591f620f22d30f4ce090c | |
parent | 39c626ae47c469abdfd30c6e42eff884931380d6 (diff) |
forget_original_parent: do not abuse child->ptrace_entry
By discussion with Roland.
- Use ->sibling instead of ->ptrace_entry to chain the need to be
release_task'd childs. Nobody else can use ->sibling, this task
is EXIT_DEAD and nobody can find it on its own list.
- rename ptrace_dead to dead_childs.
- Now that we don't have the "parallel" untrace code, change back
reparent_thread() to return void, pass dead_childs as an argument.
Actually, I don't understand why do we notify /sbin/init when we
reparent a zombie, probably it is better to reap it unconditionally.
[akpm@linux-foundation.org: s/childs/children/]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Metzger, Markus T" <markus.t.metzger@intel.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | kernel/exit.c | 87 |
1 files changed, 41 insertions, 46 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 506693dfdd4..029415d9f82 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -726,46 +726,6 @@ static void exit_mm(struct task_struct * tsk) mmput(mm); } -/* Returns nonzero if the child should be released. */ -static int reparent_thread(struct task_struct *p, struct task_struct *father) -{ - int dead; - - if (p->pdeath_signal) - /* We already hold the tasklist_lock here. */ - group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p); - - list_move_tail(&p->sibling, &p->real_parent->children); - - if (task_detached(p)) - return 0; - /* If this is a threaded reparent there is no need to - * notify anyone anything has happened. - */ - if (same_thread_group(p->real_parent, father)) - return 0; - - /* We don't want people slaying init. */ - p->exit_signal = SIGCHLD; - - /* If we'd notified the old parent about this child's death, - * also notify the new parent. - */ - dead = 0; - if (!p->ptrace && - p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) { - do_notify_parent(p, p->exit_signal); - if (task_detached(p)) { - p->exit_state = EXIT_DEAD; - dead = 1; - } - } - - kill_orphaned_pgrp(p, father); - - return dead; -} - /* * When we die, we re-parent all our children. * Try to give them to another thread in our thread @@ -805,10 +765,46 @@ static struct task_struct *find_new_reaper(struct task_struct *father) return pid_ns->child_reaper; } +/* +* Any that need to be release_task'd are put on the @dead list. + */ +static void reparent_thread(struct task_struct *father, struct task_struct *p, + struct list_head *dead) +{ + if (p->pdeath_signal) + group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p); + + list_move_tail(&p->sibling, &p->real_parent->children); + + if (task_detached(p)) + 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)) + return; + + /* We don't want people slaying init. */ + p->exit_signal = SIGCHLD; + + /* If it has exited notify the new parent about this child's death. */ + if (!p->ptrace && + p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) { + do_notify_parent(p, p->exit_signal); + if (task_detached(p)) { + p->exit_state = EXIT_DEAD; + list_move_tail(&p->sibling, dead); + } + } + + kill_orphaned_pgrp(p, father); +} + static void forget_original_parent(struct task_struct *father) { struct task_struct *p, *n, *reaper; - LIST_HEAD(ptrace_dead); + LIST_HEAD(dead_children); exit_ptrace(father); @@ -821,15 +817,14 @@ static void forget_original_parent(struct task_struct *father) BUG_ON(p->ptrace); p->parent = p->real_parent; } - if (reparent_thread(p, father)) - list_add(&p->ptrace_entry, &ptrace_dead);; + reparent_thread(father, p, &dead_children); } - write_unlock_irq(&tasklist_lock); + BUG_ON(!list_empty(&father->children)); - list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) { - list_del_init(&p->ptrace_entry); + list_for_each_entry_safe(p, n, &dead_children, sibling) { + list_del_init(&p->sibling); release_task(p); } } |