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Commit 53b6f9fb authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
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ptrace: introduce ptrace_reparented() helper 



Add another trivial helper for the sake of grep.  It also auto-documents the
fact that ->parent != real_parent implies ->ptrace.

No functional changes.

Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Acked-by: default avatarRoland McGrath <roland@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2800d8d1

include/linux/ptrace.h

+4 −0
Original line number Diff line number Diff line
@@ -98,6 +98,10 @@ extern void ptrace_untrace(struct task_struct *child); 
extern int ptrace_may_attach(struct task_struct *task);

extern int __ptrace_may_attach(struct task_struct *task);



static inline int ptrace_reparented(struct task_struct *child)

{

	return child->real_parent != child->parent;

}

static inline void ptrace_link(struct task_struct *child,

			       struct task_struct *new_parent)

{

kernel/exit.c

+4 −5
Original line number Diff line number Diff line
@@ -698,7 +698,7 @@ reparent_thread(struct task_struct *p, struct task_struct *father, int traced) 
	if (unlikely(traced)) {

		/* Preserve ptrace links if someone else is tracing this child.  */

		list_del_init(&p->ptrace_list);

		if (p->parent != p->real_parent)

		if (ptrace_reparented(p))

			list_add(&p->ptrace_list, &p->real_parent->ptrace_children);

	} else {

		/* If this child is being traced, then we're the one tracing it
@@ -865,8 +865,8 @@ static void exit_notify(struct task_struct *tsk, int group_dead) 
	 * only has special meaning to our real parent.

	 */

	if (!task_detached(tsk) && thread_group_empty(tsk)) {

		int signal = (tsk->parent == tsk->real_parent)

				? tsk->exit_signal : SIGCHLD;

		int signal = ptrace_reparented(tsk) ?

				SIGCHLD : tsk->exit_signal;

		do_notify_parent(tsk, signal);

	} else if (tsk->ptrace) {

		do_notify_parent(tsk, SIGCHLD);
@@ -1269,8 +1269,7 @@ static int wait_task_zombie(struct task_struct *p, int noreap, 
		return 0;

	}



	/* traced means p->ptrace, but not vice versa */

	traced = (p->real_parent != p->parent);

	traced = ptrace_reparented(p);



	if (likely(!traced)) {

		struct signal_struct *psig;