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 <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>
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 @@
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 @@
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 @@
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 @@
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);
+ }
}
/*