From 53b6f9fbd3b63af14b4f6268e8b5b80d178d05bc Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@tv-sign.ru>
Date: Wed, 30 Apr 2008 00:53:13 -0700
Subject: [PATCH] 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: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
include/linux/ptrace.h | 4 ++++
kernel/exit.c | 9 ++++-----
2 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index ebe0c17039cf..f98501ba557e 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -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)
{
diff --git a/kernel/exit.c b/kernel/exit.c
index 879ed6e1c883..0da2921b1e7f 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -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;
--
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