From 39c626ae47c469abdfd30c6e42eff884931380d6 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Thu, 2 Apr 2009 16:58:18 -0700 Subject: forget_original_parent: split out the un-ptrace part By discussion with Roland. - Rename ptrace_exit() to exit_ptrace(), and change it to do all the necessary work with ->ptraced list by its own. - Move this code from exit.c to ptrace.c - Update the comment in ptrace_detach() to explain the rechecking of the child->ptrace. Signed-off-by: Oleg Nesterov Cc: "Eric W. Biederman" Cc: "Metzger, Markus T" Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/exit.c | 95 ++++------------------------------------------------------- 1 file changed, 6 insertions(+), 89 deletions(-) (limited to 'kernel/exit.c') diff --git a/kernel/exit.c b/kernel/exit.c index 3e09b7c..506693d 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -61,11 +61,6 @@ DEFINE_TRACE(sched_process_wait); static void exit_mm(struct task_struct * tsk); -static inline int task_detached(struct task_struct *p) -{ - return p->exit_signal == -1; -} - static void __unhash_process(struct task_struct *p) { nr_threads--; @@ -731,85 +726,6 @@ static void exit_mm(struct task_struct * tsk) mmput(mm); } -/* - * Called with irqs disabled, returns true if childs should reap themselves. - */ -static int ignoring_children(struct sighand_struct *sigh) -{ - int ret; - spin_lock(&sigh->siglock); - ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || - (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); - spin_unlock(&sigh->siglock); - return ret; -} - -/* Returns nonzero if the tracee should be released. */ -int __ptrace_detach(struct task_struct *tracer, struct task_struct *p) -{ - __ptrace_unlink(p); - - if (p->exit_state != EXIT_ZOMBIE) - return 0; - /* - * If it's a zombie, our attachedness prevented normal - * parent notification or self-reaping. Do notification - * now if it would have happened earlier. If it should - * reap itself we return true. - * - * 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, tracer)) - do_notify_parent(p, p->exit_signal); - else if (ignoring_children(tracer->sighand)) - p->exit_signal = -1; - } - - if (!task_detached(p)) - return 0; - - /* Mark it as in the process of being reaped. */ - p->exit_state = EXIT_DEAD; - return 1; -} - -/* - * Detach all tasks we were using ptrace on. - * Any that need to be release_task'd are put on the @dead list. - * - * Called with write_lock(&tasklist_lock) held. - */ -static void ptrace_exit(struct task_struct *parent, struct list_head *dead) -{ - struct task_struct *p, *n; - - list_for_each_entry_safe(p, n, &parent->ptraced, ptrace_entry) { - if (__ptrace_detach(parent, p)) - list_add(&p->ptrace_entry, dead); - } -} - -/* - * Finish up exit-time ptrace cleanup. - * - * Called without locks. - */ -static void ptrace_exit_finish(struct task_struct *parent, - struct list_head *dead) -{ - struct task_struct *p, *n; - - BUG_ON(!list_empty(&parent->ptraced)); - - list_for_each_entry_safe(p, n, dead, ptrace_entry) { - list_del_init(&p->ptrace_entry); - release_task(p); - } -} - /* Returns nonzero if the child should be released. */ static int reparent_thread(struct task_struct *p, struct task_struct *father) { @@ -894,12 +810,10 @@ static void forget_original_parent(struct task_struct *father) struct task_struct *p, *n, *reaper; LIST_HEAD(ptrace_dead); + exit_ptrace(father); + write_lock_irq(&tasklist_lock); reaper = find_new_reaper(father); - /* - * First clean up ptrace if we were using it. - */ - ptrace_exit(father, &ptrace_dead); list_for_each_entry_safe(p, n, &father->children, sibling) { p->real_parent = reaper; @@ -914,7 +828,10 @@ static void forget_original_parent(struct task_struct *father) write_unlock_irq(&tasklist_lock); BUG_ON(!list_empty(&father->children)); - ptrace_exit_finish(father, &ptrace_dead); + list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) { + list_del_init(&p->ptrace_entry); + release_task(p); + } } /* -- cgit v1.1